Composite catalyst material and fuel cell including same

Abstract

The present disclosure relates to a fuel cell comprising a composite catalyst material comprising (N-doped) carbon nanofoam, a catalytic metal, and a conductive material including a conductive polymer, which can advantageously be operated at lower temperatures than standard fuel cells.

Description

[Technical field]

[0001] The present disclosure relates to fuel cells, particularly polymer electrolyte membrane (PEM) type fuel cells. In particular, the present disclosure relates to fuel cells configured to operate in both redox and regenerative modes. The present disclosure also relates to one or more catalysts for such fuel cells. The present disclosure also relates to methods of forming said catalysts. [Background technology]

[0002] Conventional electrochemical fuel cells convert fuel and oxidant into electrical energy and reaction products. The typical layout of a conventional fuel cell includes a solid polymer ion transport membrane sandwiched between an anode and a cathode. The polymer membrane allows protons to pass through the membrane but blocks the passage of electrons. Generally, both the anode and cathode are formed from an electrically conductive porous material, such as porous carbon, to which small particles of platinum and / or other precious metal catalysts are bonded.

[0003] The anode and cathode are often formed on adjacent surfaces of a membrane, a combination commonly referred to as a membrane electrode assembly (MEA).

[0004] Typically, the polymer membrane and porous electrode layers are sandwiched between flow plates. The flow plates in conventional fuel cells serve to deliver reactants to the anode and cathode and remove reaction products. Fuel cells may include porous gas diffusion layers fabricated to ensure efficient diffusion of gases to and from the anode and cathode surfaces and to aid in the management of water vapor and liquid water.

[0005] In a typical application, one of the flow plates may include an anode fluid flow field including multiple channels for delivering hydrogen gas to the anode, and the other of the flow plates may include a cathode flow field including multiple channels for delivering an oxidant (e.g., oxygen gas) to the cathode. The flow fields may be arranged to remove reaction products or water vapor.

[0006] Because the voltage generated by a single fuel cell is very low, conventionally multiple cells are connected in series, such that the conductive flow plate on the cathode side of one cell is placed in electrical contact with the adjacent flow plate on the anode side of the next cell.

[0007] To simplify the construction of series-connected arrays or "stacks" of fuel cells, the prior art has proposed utilizing a single flow plate shared between adjacent cells, called a bipolar plate. At the ends of the stack, i.e., the first and last fuel cells in the stack, the flow plate is sometimes referred to as an "end plate."

[0008] The present invention seeks to provide improvements in the design of fuel cells and fuel cell stacks formed from such fuel cells. Summary of the Invention

[0009] The present disclosure relates to highly mesoporous (N-doped) carbon nanofoam materials that find particular application as supporting scaffolds for catalysts in fuel cells, composite catalyst materials comprising (N-doped) carbon nanofoam materials, and fuel cells comprising the composite catalyst materials.

[0010] According to one aspect of the present disclosure, there is provided a fuel cell including one or more first catalyst layers, the one or more first catalyst layers comprising: A catalyst comprising a metal or metal oxide of Groups 4 to 11; a conductive material including a conductive polymer; A fuel cell is provided, wherein the catalyst and the conductive material are supported by a (N-doped) carbon nanofoam material.

[0011] In one or more embodiments, a polymer electrolyte membrane (101) having a first electrode (102) on one side and a second electrode (103) on the opposite side, the polymer electrolyte membrane (101), the first electrode (102) and the second electrode (103) being disposed between a first plate (104) and a second plate (105); a first plate (104) disposed adjacent to the first electrode (102) and a second plate (105) disposed adjacent to the second electrode (105), the first plate comprising a polymer electrolyte membrane (101) optionally including flow channels formed on a surface thereof facing the first electrode (102) and configured to supply fluid to and receive fluid from the first electrode (102); one or more first catalyst layers located between the first plate (104) and the second plate (105), The one or more first catalyst layers include A catalyst comprising a metal or metal oxide of Groups 4 to 11; a conductive material including a conductive polymer; A fuel cell (100) is provided comprising one or more first catalyst layers, wherein the catalyst and the conductive material are supported by a (N-doped) carbon nanofoam material.

[0012] While the present disclosure is susceptible to various modifications and alternative forms, specific aspects thereof have been shown by way of example in the drawings and will be described in detail. It will be understood, however, that other embodiments beyond the specific embodiments described are also possible. All modifications, equivalents, and alternative embodiments falling within the spirit and scope of the appended claims are also covered.

[0013] The above discussion is not intended to represent every example embodiment or every implementation falling within the scope of the present or future set of claims. The following figures and detailed description also illustrate various example embodiments. Various example embodiments can be more fully understood in view of the following detailed description in conjunction with the accompanying drawings.

[0014] One or more embodiments will now be described, by way of example only, with reference to the accompanying drawings. [Brief description of the drawings]

[0015] [Figure 1] 1 illustrates an exemplary embodiment of a fuel cell and diagrammatically illustrates a fuel cell stack formed from such fuel cells. [Figure 2a] 1 shows an SEM micrograph of the N-doped carbon nanofoam material formed in Example 1. [Figure 2b] 1 shows an SEM micrograph of the N-doped carbon nanofoam material formed in Example 1. [Diagram 3] Figure 1 shows the RDE polarization curves of the test cell containing the composite catalyst material Co-PANI-PPyTsOH / N-doped carbon nanofoam. [Figure 4] 1 shows the difference in performance between test cells equipped with electrodes containing Co-PPy / N-doped carbon nanofoam catalyst and Co-PpyTsOH / N-doped carbon nanofoam catalyst. [Figure 5a] 4 shows the performance (potential vs. current density) of various composite catalyst materials formed under different conditions. [Figure 5b] 4 shows the performance (potential vs. current density) of various composite catalyst materials formed under different conditions. [Figure 5c] 4 shows the performance (potential vs. current density) of various composite catalyst materials formed under different conditions. [Figure 5d] 4 shows the performance (potential vs. current density) of various composite catalyst materials formed under different conditions. [Figure 5e] 4 shows the performance (potential vs. current density) of various composite catalyst materials formed under different conditions. [Figure 5f] 4 shows the performance (potential vs. current density) of various composite catalyst materials formed under different conditions. [Figure 6a] FIG. 13 shows a TEM image of the ORR composite catalyst material PANI:polypyrrole-TsOH:(N-doped) carbon nanofoam material:CoP@a-CoOx formed in Example 3. [Figure 6b] FIG. 13 shows a TEM image of the ORR composite catalyst material PANI:polypyrrole-TsOH:(N-doped) carbon nanofoam material:CoP@a-CoOx formed in Example 3. [Figure 7a] FIG. 13 shows a TEM image of the OER composite catalyst material PANI:polypyrrole-TsOH:N-doped carbon nanofoam material:cobalt formed in Example 5. [Figure 7b] FIG. 13 shows a TEM image of the OER composite catalyst material PANI:polypyrrole-TsOH:N-doped carbon nanofoam material:cobalt formed in Example 5. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] The present disclosure provides various examples of different configurations of fuel cells that include (N-doped) carbon nanofoam materials, and in particular different configurations of (N-doped) carbon nanofoam materials that find various applications as components in composite catalyst materials in fuel cells. Particularly preferred types of (N-doped) carbon nanofoam materials used in the embodiments of the present disclosure are described in more detail below.

[0017] An exemplary embodiment of a fuel cell is described.

[0018] In one or more embodiments, a fuel cell may be configured to operate in both a conventional redox mode, in which fuel and oxidant are consumed to generate an electric current and one or more reaction products, and a regenerative mode, in which a potential difference is applied to the fuel cell and at least one of the one or more reaction products is electrolyzed to form the fuel. Thus, one or more exemplary embodiments of a fuel cell include a reversible fuel cell. In one or more embodiments, one or more catalyst layers are provided to enable operation in the redox mode and the regenerative mode.

[0019] In one or more embodiments, a fuel cell can include a fuel storage material along with, i.e., alongside, or as a structure or layer forming part of, an electrode of the fuel cell, thereby providing storage of fuel within the fuel cell. In one or more embodiments, a fuel storage material is provided between a first plate that includes an active area of ​​the fuel cell and a second plate.

[0020] In one or more embodiments, the fuel is protons, and the fuel storage material is configured to store the fuel.

[0021] It will be understood that a fuel cell may be configured to provide the redox mode and the regenerative mode and not include the fuel storage material. It will also be understood that a fuel cell may be configured to include the fuel storage material without being configured to operate in the redox mode and the regenerative mode. For example, a fuel cell may be configured to operate only in the regenerative mode, thereby functioning to store fuel in a fuel storage material for extraction. Alternatively, a fuel storage material may be supplied with fuel and the fuel cell may be configured to operate only in the redox mode.

[0022] It will be appreciated that references to a "fuel cell" may also be taken to refer generally to a stack of fuel cells, provided that the shape of the fuel cell is replicated throughout the stack.

[0023] 1 illustrates an example of a fuel cell 100 according to one embodiment of the present disclosure. The fuel cell 100 includes a polymer electrolyte membrane, or "PEM," 101. The PEM 101 includes a semi-permeable membrane and can be configured to conduct protons while functioning as an electronic insulator and reactant barrier.

[0024] The PEM 101 may be formed from an ionomer, which in one or more embodiments may include a fluorinated acid polymer.

[0025] Suitable fluorinated acid polymers, particularly those in which the acidic groups are sulfonic acid or sulfonimide groups, are described below, with highly fluorinated and perfluorinated polymers having these acidic groups being particularly preferred.

[0026] Suitable polymers for use in the PEM include those sold under the Nafion® trademark, such as Nafion® 211 and Nafion® 212.

[0027] The thickness of the PEM may be from 5 μm to 200 μm. In a preferred embodiment, the thickness of the PEM may be from 10 μm to 100 μm, preferably from 20 μm to 75 μm.

[0028] The fuel cell 100 includes a porous first electrode 102 on one side of the PEM and a porous second electrode 103 on the opposite side of the PEM. Thus, the first electrode 102, second electrode 103, and PEM may be formed as a series of layers, and the arrangement may be collectively referred to as a membrane electrode assembly, or "MEA."

[0029] The PEM 101, first electrode 102, and second electrode 103 are sandwiched between a first plate 104 and a second plate 105. The first plate and second plate 104, 105 may comprise non-porous rigid plates that provide structural integrity to the fuel cell 100. In other embodiments, the plates may be flexible.

[0030] The first plate 104 is positioned adjacent, e.g., directly adjacent, to the first electrode 102. The second plate 105 is positioned adjacent, e.g., directly adjacent, to the second electrode (105). In one or more embodiments, the first plate includes an optional flow channel (not shown in FIG. 1 ) formed in its surface 106 that faces the first electrode 102. The flow channel may be configured to receive a fluid, such as an oxidant, from one or more fluid inlets (shown diagrammatically at 107) and distribute the fluid over the surface of the first electrode 102.

[0031] The fuel cell 100 may include gas diffusion layers (not shown in FIG. 1 ) for further distributing the fluids from the flow paths to the first electrode 102. Gas diffusion layers may also be optionally included at other locations, such as between the first electrode 102 and the PEM 101, between the PEM 101 and the second electrode 103, and between the second electrode and the second plate 105.

[0032] Suitable materials for use as gas diffusion layers include carbon cloth.

[0033] Preferably, the gas diffusion layer has a hydrophobic coating. A suitable hydrophobic coating is, for example, PTFE.

[0034] The flow channels may alternatively or additionally be configured to receive fluids, such as one or more reaction products, from the first electrode 102. The first plate 104 may further include one or more fluid outlets (shown diagrammatically at 108) for receiving said fluids from the flow channels.

[0035] In one or more embodiments, the second plate 105 includes optional channels (not shown in FIG. 1 ) formed in its surface 110 that faces the second electrode 103. The channels can be configured to receive a fluid, such as a fuel, from a fluid inlet (not shown) and distribute the fluid over the surface of the second electrode 103.

[0036] The fuel cell 100 may include gas diffusion layers to further distribute the fluid from the flow paths to the second electrode 103 .

[0037] The flow channels may alternatively or additionally be configured to receive a fluid from the first electrode 102, such as unreacted fuel from a fluid inlet or fuel from the second electrode 103. The second plate 105 may further include one or more fluid outlets (not shown) for receiving said fluids from the flow channels.

[0038] Each plate 104, 105 may include a current tab 112, 113 through which an electrical current may flow during use. Thus, in such a configuration, the first electrode 102 is electrically connected to the first plate 104 and the second electrode 103 is electrically connected to the second plate 105. It will be appreciated that other means for providing an electrical circuit between the first and second electrodes 102, 103 may be provided, which may or may not include the first and / or second plates 104, 105.

[0039] The fuel cell 100 may include one or more first catalyst layers 114, 115 between the first plate 104 and the polymer electrolyte membrane 101. The one or more first catalyst layers may be configured to provide active sites for catalytic activity for one or both of the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER). Suitable catalyst materials for use in the catalyst layers are described in more detail below.

[0040] In one or more embodiments, an OER catalyst layer can be provided on a side 114 of the first electrode that faces the first plate 104. In one or more embodiments, an ORR catalyst layer can be provided on a side 115 of the first electrode that faces the PEM 101.

[0041] In this and one or more other embodiments, the first electrode 102 is porous, allowing fluid to pass through the electrode and reach the PEM 101 .

[0042] Suitable materials from which the porous first electrode may be formed include frits, foams, meshes or nonwovens of conductive materials that preferably provide a tortuous path to allow the passage of fluid.

[0043] Suitable materials for the first electrode include carbon cloth and metal frit.

[0044] The conductive material may be a metal, preferably a metal with low reactivity. Suitable metals for the first electrode include titanium, vanadium, chromium, manganese, iron, cobalt, nickel and copper. Preferably, the metal for the first electrode includes titanium.

[0045] In one or more embodiments, the porous first electrode has a pore size of 5-100 μm, typically 20-50 μm, preferably 20-40 μm, and most preferably 30-35 μm.

[0046] The first electrode is usually coated with a hydrophobic material that may protect the electrode from water that may be present in the fuel cell (as well as perform other functions).

[0047] The one or more first catalyst layers, in one or more embodiments, are provided as a coating on the first electrode 102. However, in other embodiments, one or more of the one or more first catalyst layers 114, 115 may be provided as a separate layer separate from but disposed adjacent to the first electrode 102.

[0048] In this example, the OER first catalyst layer 114 comprises a coating on one side of the first electrode 102 that faces the first end plate 104. In this example, the ORR first catalyst layer 115 comprises a coating on the opposite side of the first electrode 102 that faces the PEM 101. In such an example, the first electrode 102 may be considered as a conductive support material for the first catalyst layers 114, 115.

[0049] The fuel cell 100 may include one or more second catalyst layers 116, 117 between the second plate 105 and the polymer electrolyte membrane 101. The one or more second catalyst layers may be configured to provide active sites for catalytic activity for one or both of the hydrogen reduction reaction (HRR) and the hydrogen evolution reaction (HER).

[0050] In one or more embodiments, a HER catalyst layer can be provided on a side 116 of the second electrode that faces the second plate 105. In one or more embodiments, a HRR catalyst layer can be provided on a side 117 of the second electrode that faces the PEM 101.

[0051] Suitable catalytic materials for use as HER and HRR catalysts are described in more detail below.

[0052] One or more second catalyst layers 116, 117 are provided as a coating on the second electrode 103 in one or more embodiments.

[0053] However, in other embodiments, one or more of the one or more second catalyst layers 116, 117 may be provided as a separate layer separate from but disposed adjacent to the second electrode 103. In this embodiment, the HER second catalyst layer 116 includes a coating on one side of the second electrode 103 that faces the second end plate 105. In this embodiment, the HRR second catalyst layer 117 includes a coating on the opposite side of the second electrode 103 that faces the PEM 101. In such embodiments, the second electrode 103 may be considered to be a conductive support material for said second catalyst layers 116, 117.

[0054] The fuel cell 100 may optionally include a gas diffusion layer 118 between the PEM 101 and the second electrode 103. The gas diffusion layer may include a carbon-based fabric or a carbon-containing fabric or cloth.

[0055] The gas diffusion layer 118 may be configured to diffuse and distribute fluid between the PEM 101 and the second electrode 103, or vice versa. This configuration minimizes the risk of developing areas of high concentration of fluid flux (so-called "hot spots"), which may extend the life of the PEM 101 and / or the second electrode (103), or any storage material or catalyst layer associated with the second electrode.

[0056] In this embodiment and in one or more embodiments, the fuel cell 100 is configured to operate in a redox mode and a regenerative mode. In the redox mode, the fuel cell 100 is configured to supply fuel to the second electrode 103 and an oxidant, such as oxygen from the air, to the first electrode 102 to generate an electric current between the first electrode 102 and the second electrode 103 and generate reaction products at the first electrode 102. The fuel may be supplied from a fuel source external to the fuel cell 100 and may be introduced via a fluid inlet in the second flow plate 105. Alternatively, or in addition, the fuel may be supplied to the second electrode 103 from a fuel storage material.

[0057] In a hydrogen-based fuel cell, the fuel includes hydrogen, the oxidant includes oxygen from air or an oxygen source, and the reaction product includes water.

[0058] In regenerative mode, the fuel cell is configured such that a reaction product (such as water in the case of a hydrogen-based fuel cell) is provided to the first electrode 102. A potential difference is applied between the first electrode 102 and the second electrode 103 by a power source (not shown), thereby producing the fuel (e.g., hydrogen) at the second electrode 103.

[0059] The fuel cell 100 may include a fuel storage material as part of or adjacent to the second electrode 103, and may at least partially supply the fuel to the second electrode 103 in a redox mode, and / or may at least partially store the fuel produced at the second electrode 103 in a regenerative mode.

[0060] In this and one or more embodiments, the second electrode 103 is formed of the fuel storage material. Thus, the fuel storage material may be an integral part of the second electrode 103.

[0061] In other embodiments, the fuel storage material may include a separate layer that is separate from the second electrode 103 but may be positioned adjacent to the second electrode 103 within the fuel cell 100, i.e., at least partially between the first plate 104 and the second plate 105.

[0062] Fuel storage materials may include materials that store hydrogen or hydrogen ions chemically and / or electrostatically. Examples of such materials are provided below.

[0063] In one or more embodiments, the PEM is bonded to a gas diffusion layer (e.g., a carbon-based conductor such as carbon paper, carbon cloth, or carbon fiber, preferably carbon paper) and the other side of the gas diffusion layer is coated with a HER catalyst, which is adjacent to the anode to facilitate the transfer of electrons.

[0064] This configuration has been found to be advantageous when the anode serves as the fuel storage material, where the hydrogen generated by the HER is also captured. It has been found that when the HER is directly coated on the anode, hot spots can occur, leading to reduced hydrogen storage efficiency.

[0065] In one or more embodiments, the fuel cell 100 includes a peripheral gasket 120 sandwiched between a first plate 104 and a second plate 105 and configured to contain at least the polymer electrolyte membrane 101, the first electrode 102, the second electrode 103, one or more first catalyst layers, and one or more second catalyst layers. The gasket 120 may be made of silicone or vulcanized rubber. In other examples, the fuel cell 100 may be surrounded by a housing that contains the layers, reactants, and the reaction products.

[0066] In one or more embodiments, the fuel cell 100 may be part of a fuel cell stack 121 that includes multiple fuel cells arranged in series with each other. In FIG. 1, a box 122 represents a schematic representation of a fuel cell adjacent to the fuel cell 100 in the fuel cell stack 121. The adjacent fuel cell 122 is substantially identical to the fuel cell 100. Thus, in this embodiment, the second plate 105 of the fuel cell 100 is electrically connected to a first plate of an adjacent fuel cell 122 of the at least two fuel cells. In one or more embodiments, the electrically connected first and second plates of the fuel cells of the stack 121 may be provided by a single plate known as a bipolar plate. A bipolar plate may have a flow path for the second electrode of one fuel cell of the fuel cell stack and a flow path for the first electrode of an adjacent fuel cell 122 of the fuel cell stack. Thus, the plate 105 may include a bipolar plate.

[0067] The first and second plates of the fuel cells of the stack 121, which may be provided in part by bipolar plates, may include an inlet manifold 124 that penetrates the stack to deliver one or more of fuel and oxidant to the fuel cells therein. Similarly, the fuel cell stack 121 may include an outlet manifold 125 that receives fuel and / or oxidant and / or reaction product(s) from each fuel cell therein.

[0068] In use, in redox mode, the fuel cell 100 (or fuel cell stack 121) may be supplied with fuel, such as hydrogen from a fuel storage material at the second electrode 103 and / or an external fuel source. The fuel from the external source may be flowed (such as by a pump) through the flow channels of the second plate 105. In redox mode, an oxidant, which may include air, may be flowed (such as by a pump (not shown)) through the flow channels of the first plate 105. When supplied with reactants, the first electrode 102 constitutes the cathode and the second electrode 103 constitutes the anode, and an electrochemical reaction is provided by the fuel cell to generate a potential difference, which causes a current to flow between the first and second electrodes 102, 103 via an external circuit between the current tabs 112, 113. One or more second catalysts 117, 118 act to reduce the hydrogen fuel, with protons passing through the PEM 101 and electrons passing through the external circuit. The reaction products protons and oxidant at the first electrode 102. One or more first catalysts 114, 115 may be provided to catalyze the formation of the reaction products.

[0069] Unused fuel on the "anode" side may be absorbed or captured by the hydrogen storage material and / or flow through the channels of the second plate 105 and exit via a fuel outlet manifold, which may constitute a shared manifold 125. Unused oxidant and reaction product(s), such as water, may flow through the channels of the first plate 104 and exit via the outlet manifold 125.

[0070] In use, in regenerative mode, the fuel cell 100 (or fuel cell stack 121) may be supplied with reactants, including the reaction product of water in the case of a hydrogen fuel cell. In one or more embodiments, the fuel cell may include a mist or vapor generator 123 for generating an atomized flow of reactants to the first electrode 102 via a flow passage in the first plate 104. The vapor generator 123 may include one of an ultrasonic-based vapor generator, a piezoelectric-based vapor generator, or may include a flow pumped using an atomizing nozzle. In one or more embodiments, the reactant flow, which may include the reactants as vapor, is not heated. Thus, the vapor may be heated by the operation of the fuel cell, and in one or more embodiments, no active heating of the reactants is provided.

[0071] In one or more embodiments, the reactant streams are provided at a rate of 10-100 ml / min per fuel cell 100. Preferably, the reactant streams are provided at a rate of 10-90 ml / min per fuel cell 100, more preferably at a rate of 10-50 ml / min. Typically, the reactant streams are provided at a rate of 12-25 ml / min per fuel cell, preferably at a rate of 15-20 ml / min. In one or more embodiments, the reactants are provided at a rate of 1×10 5 ~8×10 5 The pressure is supplied at 100 Pa.

[0072] Fuel cells including the catalytic materials disclosed herein are advantageous because they can be operated at relatively low temperatures, with typical operating temperatures ranging from 60°C to 85°C, preferably from 65°C to 80°C.

[0073] These operating temperatures are typically achieved without external influences, i.e. the device generates heat through an exothermic reaction. Overheating can be easily avoided by using cold water as the fuel source. Additional cooling measures for the entire stack are optional, although usually not required.

[0074] Preferably, the fuel cell stack does not include cooling elements such as fins or channels for cooling fluid that can remove heat from the fuel cells.

[0075] In the regenerative mode, a current flow is provided between the current tabs 112, 113. The current flow may be provided by applying a DC potential difference between the first and second electrodes via the current tabs 112, 113. One or more first catalyst layers 114, 115 may act to catalyze the reduction of a reactant, for example, water. In the regenerative mode, with the reactants provided, the first electrode 102 constitutes the anode and the second electrode 103 constitutes the cathode. Protons generated at the first electrode 102 may be stored in the fuel storage material of the second electrode 103. In one or more embodiments, fuel that is not absorbed or captured by the fuel storage material may flow through the second electrode 103 and be received in the flow passages of the second plate 105, thereby removing the unabsorbed fuel from the fuel cell 100. In other embodiments, the fluid inlets and outlets to the flow passages of the second plate 105 may be closed and the fuel cell 100 may be configured to saturate the fuel storage material with a fuel, such as hydrogen. In such an embodiment, assuming the fuel is provided by and absorbed by the fuel storage material, the channels in the second plate 105 may not be provided since fuel does not need to flow therethrough. Unreacted reactants, such as water, may flow through the channels in the first plate 104 and exit through an outlet.

[0076] 1 shows a fuel cell having an integrated fuel storage material that is functional by providing suitable catalyst layers that operate in both redox and regenerative modes, although in one or more embodiments only a portion of the above structure may be provided.

[0077] For example, in one or more embodiments, the fuel storage material may not be integral with the fuel cell 100, but instead, fuel produced in the regenerative mode may be provided to a fuel reservoir external to the fuel cell 100 via channels and outlets in the second plate 105. In an exemplary embodiment, one or more first catalysts 114, 115 and one or more second catalysts 117, 116 may be provided, but the second electrode 103 may include a material that does not act to store fuel produced in the regenerative mode.

[0078] In further examples, the fuel cell 100 may be configured to include the fuel storage material but operate only in redox mode. Thus, in one or more examples, only the catalyst(s) acting to promote the redox reaction may be provided. In further examples, the one or more first catalysts may not be provided, and one or more second catalysts may be provided. In such examples, the fuel storage material of the second electrode 103 may be "recharged" from an external fuel source, rather than by operation in a regenerative mode. Thus, during "recharge", gaseous hydrogen may be provided to the second electrode 105 via the channels of the second plate 105, and one or more second catalyst layers 117, 116 may be provided to reduce the gaseous hydrogen to protons for storage in the fuel storage material.

[0079] In further embodiments, the fuel cell 100 may include the fuel storage material but be configured to operate only in a redox mode. It will be appreciated that while the first and second catalyst layers act to enhance the reaction rate of the fuel cell, this may not be necessary in some applications. Thus, in one or more embodiments, the fuel cell 100 may include the fuel storage material but not include one or more of the first and second catalyst layers 114, 115, 116, 117.

[0080] In further embodiments, the fuel cell 100 may be configured to operate only in regenerative mode. Thus, one or more first catalyst layers 114 may be provided, but one or more second catalyst layers 116, 117 may not be present. In such embodiments, a fuel storage material may or may not be provided. In embodiments where one is not provided, fuel produced in regenerative mode may be captured in a fuel reservoir external to the fuel cell 100.

[0081] Examples of one or more first catalyst layers 114, 115 and one or more methods of forming said layers are now described. Examples of one or more second catalyst layers 116, 117 and one or more methods of forming said layers are now described. Additionally, one or more examples of fuel storage materials and one or more methods of forming said fuel storage materials are now described.

[0082] Some of the specific materials that can be used in fuel cells are described in more detail below.

[0083] (N-doped) Carbon Nanofoam Materials The present disclosure provides (N-doped) carbon nanofoam materials that have excellent properties as components of redox catalysts in fuel cells.

[0084] As used herein, the term "(N-doped)" means that the material is optionally N-doped. Thus, "(N-doped) carbon nanofoam material" refers to a carbon nanofoam material that may be optionally N-doped.

[0085] As used herein, "C nf " may be used to refer to carbon nanofoam materials.

[0086] As used herein, "C nf -N x " may be used to denote N-doped carbon nanofoam material.

[0087] Carbon materials provide useful electrocatalysts due to their high surface area, high conductivity, and low cost. Various types of carbon materials suitable for use as electrocatalysts are disclosed in X. Wang et al., Adv. Energy Mater., 2017, 7, 1700544.

[0088] Non-metallic atoms such as N, P, S, and B can be doped into carbon structures, resulting in multiple possible configurations of doped carbon materials. These heteroatoms are more electronegative than carbon, making adjacent carbon atoms electron-deficient, thereby facilitating the adsorption of oxygen into the carbon nanostructure. Doped carbon structures can take on a variety of forms, including nanotubes, sheets, or particulate carbon materials.

[0089] Of these doping atoms, N is advantageous as it provides a stable material with the desired balance of properties. Specifically, when the material is modified with a catalytic metal, N-doping can result in faster electron transfer, reduced bulk resistance, and increased binding efficiency. In contrast, doping with S and P typically makes the carbon more acidic, increasing the pH sensitivity of the material. Modification with S typically leaves the carbon material with a highly reactive surface, which can lead to reduced lifetime and side reactions.

[0090] The (N-doped) carbon nanofoam materials of the present disclosure are characterized as superstructures of coalesced (N-doped) carbon nanofoam particles, said particles having diameters between 0.005 μm and 25 μm.

[0091] Preferably, the nanofoam particles have a diameter of 0.01 to 15 μm, preferably 0.01 to 5 μm, more preferably 0.01 to 2 μm.

[0092] The diameter of the nanofoam particles can be measured by SEM. Typically, such a process measures the largest dimension of the particle.

[0093] The average diameter may be calculated by taking the average of the largest dimension measurements of ten separate nanoform particles.

[0094] In one embodiment, the (N-doped) carbon nanofoam material has a superstructure of coalesced (N-doped) carbon nanofoam particles, said superstructure having a tortuous path of open pores that is at least 3 times the average diameter of the nanofoam particles, preferably at least 5 times the average diameter of the nanofoam particles, for example 5-100 times, preferably 5-50 times the average diameter of the nanofoam particles.

[0095] The open pores typically have irregular shapes, as illustrated in Figure 2b. Pore size can be determined by SEM, and the average size of any given pore is defined as the average of the largest and smallest dimensions of that pore as determined by SEM.

[0096] The average size of the pores in the superstructure varies depending on the particle size of the nanofoam particles and is typically between 10 and 100 μm, for example about 1 μm for nanofoam particles.

[0097] In an alternative embodiment, the average size of the pores in the superstructure is typically between 0.2 μm and 2 μm.

[0098] The average pore size can be determined by averaging 10 average pore sizes determined by SEM.

[0099] In one embodiment, the (N-doped) carbon nanofoam material is 300 mg / cm 3 Less than 50-200 mg / cm 3 , preferably 50 to 150 mg / cm 3 has a density of

[0100] The density of the (N-doped) carbon nanofoam material can be measured by weighing the bulk material and then correlating the mass to the average elemental density.

[0101] Methods for producing carbon nanofoam are known in the art, for example, see Sattler et al., Carbon 95 (2015), pp 434-441.

[0102] An exemplary method for forming the (N-doped) carbon nanofoam material includes: i. forming a mixture of sugar, water, and a hydrocarbon mediator; ii. heating the mixture to form carbon nanofoam; iii. Optionally, heating the carbon nanofoam in an acidic nitrogen source (eg, nitric acid) to form N-doped carbon nanofoam.

[0103] Sugars suitable for use include mono-, di- and trisaccharides such as sucrose, glucose or fructose, with sucrose being preferred.

[0104] The sugar and water mixture is highly concentrated, i.e. at least 3 molar, typically at least 4 molar, e.g. about 5 molar. At such high concentrations, heating, typically at temperatures between 50°C and 85°C, e.g. 60°C to 80°C, and vigorous stirring are typically required to completely dissolve the sugar.

[0105] Typically, the concentrated sugar solution is cooled, for example to less than 50° C., before adding the carbohydrate mediator.

[0106] Suitable hydrocarbon mediators include aromatic hydrocarbons such as pyrene, chrysene, benz[a]anthracene, fluoranthene, anthracene, naphthalene, benzene and hexane, with anthracene, naphthalene and benzene being preferred, and naphthalene being most preferred.

[0107] Typically, only a small amount of the hydrocarbon mediator (such as naphthalene) is required. For example, the ratio of the hydrocarbon mediator (e.g., naphthalene) to the sugar (e.g., sucrose) is typically 1:25,000 to 1:75,000, or 1:50,000 to 1:65,000.

[0108] Step ii entails heating the mixture to form the nanofoam. The mixture is heated to a temperature and for a time sufficient to carbonize the sugars to form a particulate material.

[0109] Suitably, the mixture is heated at a temperature between 100°C and 600°C for 30 minutes to 24 hours. Heating to higher temperatures usually requires shorter heating times. For example, the mixture may be heated to 500°C for 1 hour. Alternatively, the mixture may be heated to 155°C for 5 hours. It is of course possible to heat the mixture for longer periods, but this is usually not necessary.

[0110] Preferably, the mixture is heated at a temperature of 350° C. to 600° C. for 30 minutes to 3 hours, or alternatively, the mixture is heated at a temperature of 100° C. to 300° C. for 4 hours to 12 hours.

[0111] The heating step carbonizes the material and forms the nanofoam, and is therefore typically carried out in a suitably inert vessel, such as a Teflon-coated hydrothermal reactor.

[0112] The heating step is preferably carried out in a closed reactor.

[0113] The resulting nanoform may optionally be comminuted, for example by milling, which may be carried out in a ball mill.

[0114] The resulting material is a superstructure of coalesced carbon nanofoam particles. The carbon nanofoam particles are typically mesoporous, i.e., have pores between 2 nm and 50 nm. The nanofoam particles are bonded to each other by covalent interactions, resulting in a surprisingly sustained superstructure even under mechanical stress, such as during milling.

[0115] The pore size of the mesopores can be determined by electron tunneling microscopy. In such a process, the material may be coated with a metal such as titanium by sputtering. After coating, the pore structure can be observed using a tunneling microscope, and the pore size can be determined from the image produced. Although this method produces images of the surface, it is clear from the bulk reactivity of the material that the pores extend below the surface into the structure of the carbon. Therefore, the material is best described as a mesoporous carbon nanofoam.

[0116] Nanofoam particles can vary in shape and the shape can depend on the sugar and carbohydrate mediators used, for example, glucose and naphthalene form cube-like structures.

[0117] Sucrose and naphthalene are preferred, as they produce roughly spherical particles.

[0118] The diameter of the nanofoam particles is typically 0.01 to 15 μm, preferably 0.01 to 5 μm, and more preferably 0.01 to 2 μm.

[0119] Step iii involves N-doping the carbon nanoform by heating with an acidic nitrogen source such as nitric acid (HNO3), nitrous acid (HNO), hyponitrous acid (H2N2O) or mixtures thereof, with nitric acid being preferred.

[0120] Typically, the carbon nanofoam is heated to at least 80° C. for at least 2 hours, such as at least 90° C. for at least 4 hours, preferably from 95° C. to 115° C. for at least 4 hours.

[0121] Heating is typically carried out in a suitable acid-resistant pressure vessel, such as a Teflon hydrothermal reactor.

[0122] The acidic nitrogen source (e.g., nitric acid) must be sufficiently concentrated to ensure a sufficient level of N-doping. Suitable concentrations (e.g., of nitric acid) include 3-10 molar, preferably 4-8 molar.

[0123] Treatment of carbon nanoparticles with nitric acid or an alternative acidic nitrogen source introduces N-doping into the structure, forming a mixture of pyridinic-N, pyrrolic-N, and graphitic-N sites. However, when nitric acid or an alternative acidic nitrogen source is used, the acidic conditions result in the additional formation of carboxylic acid groups on the surface of the material. In addition, pitting can occur on the surface, resulting in the loss of some of the mesoporous structure. Therefore, conditions must be controlled to provide the desired amount of doping while avoiding excessive degradation of the mesoporous structure. However, the process is mild enough to ensure that the superstructure of the coalesced particles is preserved.

[0124] Typically, after treatment with nitric acid or an alternative acidic nitrogen source, the surface pore size increases by about 2-10%.

[0125] Generally, the N content of the obtained material is 0.1-8 wt %, preferably 1-5 wt %.

[0126] The surface area of ​​the resulting material is typically between 200 and 3500 m 2 / g, preferably 400 to 3000m 2 / g, preferably 1000 to 2500m 2 / g, preferably 1000 to 2000m 2 / g. For example, 1000 to 1800 m 2 / g, preferably 1200 to 1800m 2 / g, preferably 1200 to 1600m 2 / g.

[0127] The surface area can be measured, for example, by BET isotherm at 77K using nitrogen.

[0128] The above process is an exemplary method for forming N-doped carbon nanofoam. Alternative methods are possible. For example, a mesoporous structure can be obtained by heating a mixture of sugar, water, and a hydrocarbon mediator. If the mixture contains a nitrogen source, N-doped carbon nanofoam can be formed without the need for step iii (treatment with an acidic nitrogen source).

[0129] Conductive Polymers "Conductive polymer" means 10 -7 It refers to a polymer that forms a film with a conductivity of greater than S / cm.

[0130] Suitable conductive polymers for the catalyst layer are made from at least one monomer that, when polymerized alone, forms a conductive homopolymer. Such monomers are referred to herein as "conductive precursor monomers." Monomers that, when polymerized alone, form a homopolymer that is not conductive are referred to as "non-conductive precursor monomers."

[0131] The conductive polymer may be a homopolymer or a copolymer. Conductive copolymers suitable for the catalyst layer may be made from a combination of two or more conductive precursor monomers, or one or more conductive precursor monomers with one or more non-conductive precursor monomers.

[0132] In some embodiments, the conductive polymer is made from at least one conductive precursor monomer selected from thiophenes, selenophenes, tellurophenes, pyrroles, anilines, and polyaromatic polymers. Polymers made from these monomers are referred to herein as polythiophenes, poly(selenophenes), poly(tellurophenes), polypyrroles, polyanilines, and polyaromatic polymers, respectively.

[0133] Preferably, the conductive polymer is a poly-N-aryl polymer.

[0134] The term "poly-N-aryl" refers to polymers composed of monomers containing N-heteroaromatic rings, such as pyrrole, indole, and / or monomers containing amine-substituted aromatic rings, such as aniline, 1-naphthylamine, and the like.

[0135] The term "polycyclic aromatic" refers to a compound having two or more aromatic rings. The rings may be joined by one or more bonds or may be fused together.

[0136] The term "aromatic ring" is intended to include heteroaromatic rings. A "polycyclic heteroaromatic" compound has at least one heteroaromatic ring.

[0137] In some embodiments, a pyrrole monomer contemplated for use in forming the conductive polymer in the novel composition comprises Formula II: [ka] In formula II: R 1 are independently selected to be the same or different at each occurrence and are selected from hydrogen, alkyl, alkenyl, alkoxy, alkanoyl, aryloxy, alkylaryl, arylalkyl, amino, alkylamino, dialkylamino, aryl, alkoxyalkyl, alkoxycarbonyl, acrylic acid, phosphonic acid, halogen, nitro, cyano, hydroxyl, epoxy, silane, siloxane, alcohol, benzyl, carboxylate, ether, ethercarboxylate, urethane, or Both R 1 the groups may together form an alkylene or alkenylene chain completing a 3-, 4-, 5-, 6-, or 7-membered aromatic or alicyclic ring, which ring may optionally contain one or more divalent nitrogen or oxygen atoms; and R 2is independently selected to be the same or different at each occurrence and is selected from hydrogen, alkyl, alkenyl, aryl, alkanoyl, alkylaryl, arylalkyl, amino, epoxy, silane, siloxane, alcohol, benzyl, carboxylate, ether, ethercarboxylate, urethane.

[0138] The term "alkyl," as used herein, refers to a group derived from an aliphatic hydrocarbon and includes straight-chain, branched-chain and cyclic groups which may be unsubstituted or substituted.

[0139] The term "heteroalkyl" is intended to mean an alkyl group wherein one or more of the carbon atoms within the alkyl group has been replaced with another atom, such as nitrogen or oxygen.

[0140] As used herein, the term "alkylene" refers to an alkyl group having two points of attachment.

[0141] The term "alkenyl" as used herein refers to a group derived from an aliphatic hydrocarbon having at least one carbon-carbon double bond, and includes straight-chain, branched-chain and cyclic groups which may be unsubstituted or substituted. The term "heteroalkenyl" is intended to mean an alkenyl group in which one or more carbon atoms within the alkenyl group have been replaced with another atom, such as nitrogen, oxygen, or the like.

[0142] The term "alkenylene" refers to an alkenyl group that has two points of attachment.

[0143] As used herein, the following terms with respect to substituents refer to the formulae shown below. "Alcohol" -R 3 -OH "Amide" -R 3 -C(O)N(R 6 )R 6 "Benzyl" -CH2-C6H5 "Carboxylate" -R 3 -C(O)OZ or -R 3 -OC(O)-Z "Ether" -R 3 -(OR 5 )POR 5 "Ether carboxylate" -R 3 -OR 4 -C(O)OZ or -R 3 -OF "Urethane"-R 3 -OC(O)-N(R 6 )2 wherein all "R" groups are the same or different in each occurrence; R 3 is a single bond or an alkylene group, R 4 is an alkylene group, R 5 is an alkyl group, R 6 is hydrogen or an alkyl group, p is 0 or an integer from 1 to 20; Z is H, alkali metal, alkaline earth metal, N(R 5 )4 or R 5 It is.

[0144] Any of the above groups may be further unsubstituted or substituted, and any group, including perfluorinated groups, may have one or more hydrogens replaced by F. In some embodiments, the alkyl and alkylene groups have 1 to 20 carbon atoms, preferably 1 to 4 carbon atoms.

[0145] In some embodiments, R 1 is the same or different at each occurrence and is independently selected from hydrogen, alkyl, alkenyl, alkoxy, cycloalkyl, cycloalkenyl, alcohol, benzyl, carboxylate, ether, ethercarboxylate, urethane, epoxy, silane, siloxane, and alkyl substituted with one or more of a carboxylic acid, acrylic acid, phosphate, phosphonic acid, halogen, nitro, cyano, hydroxyl, epoxy, silane, or siloxane moiety. 2is selected from hydrogen, alkyl, and alkyl substituted with one or more of a carboxylic acid, acrylic acid, phosphate, phosphonic acid, halogen, cyano, hydroxyl, epoxy, silane, or siloxy acid moiety.

[0146] Preferably, the pyrrole monomer is unsubstituted and R 1 and R 2 are both hydrogen.

[0147] In some embodiments, both R 1 taken together form a 6- or 7-membered alicyclic ring, which is further substituted with groups selected from alkyl, heteroalkyl, alcohol, benzyl, carboxylate, ether, ethercarboxylate, and urethane. These groups can improve the solubility of the monomer and the resulting polymer.

[0148] In some embodiments, both R 1 taken together form a 6- or 7-membered alicyclic ring, which is further substituted with an alkyl group. In some embodiments, both R 1 taken together form a 6- or 7-membered alicyclic ring, which is further substituted with an alkyl group having at least 1 carbon atom.

[0149] In some embodiments, both R 1 Together, -O-(CHY) m It forms -O-, m is 2 or 3, and Y is the same or different in each occurrence and is selected from hydrogen, alkyl, alcohol, benzyl, carboxylate, ether, ethercarboxylate, and urethane.

[0150] In some embodiments, at least one Y group is not hydrogen.

[0151] In some embodiments, at least one Y group is a substituent having at least one hydrogen replaced by F. In some embodiments, at least one Y group is perfluorinated.

[0152] In some embodiments, the aniline monomers contemplated for use in forming the conductive polymer in the novel compositions include the following Formula III: [ka] During the ceremony, a is 0 or an integer from 1 to 4, b is an integer from 1 to 5, with the proviso that a+b=5; and R 1 are independently selected to be the same or different at each occurrence and are selected from hydrogen, alkyl, alkenyl, alkoxy, alkanoyl, aryloxy, alkylaryl, arylalkyl, amino, alkylamino, dialkylamino, aryl, alkoxyalkyl, alkoxycarbonyl, acrylic acid, phosphonic acid, halogen, nitro, cyano, hydroxyl, epoxy, silane, siloxane, alcohol, benzyl, carboxylate, ether, ethercarboxylate, urethane, or Both R 1 The groups may be joined together to form an alkylene or alkenylene chain completing a 3-, 4-, 5-, 6-, or 7-membered aromatic or alicyclic ring, which may optionally contain one or more divalent nitrogen or oxygen atoms.

[0153] Upon polymerization, the aniline monomer units can have formula IV(a) or formula IV(b) shown below, or a combination of both formulas. [ka] [ka] During the ceremony, a, b and R 1 is as defined above.

[0154] In some embodiments, the aniline monomer is unsubstituted and a=0.

[0155] In some embodiments, a is not 0 and at least one R 1 is fluorinated. In some embodiments, at least one R 1 is perfluorinated.

[0156] In some embodiments, the fused polycyclic heteroaromatic monomers contemplated for use in forming the conductive polymers in the new compositions have two or more fused aromatic rings, at least one of which is heteroaromatic.

[0157] In some embodiments, the fused polycyclic heteroaromatic monomer has Formula V: [ka] During the ceremony, Q is NR 6 and R 6 is hydrogen or alkyl; R 8 , R 9 , R 10 , and R 11 is independently selected to be the same or different at each occurrence and is selected from hydrogen, alkyl, alkenyl, alkoxy, alkanoyl, aryloxy, alkylaryl, arylalkyl, amino, alkylamino, dialkylamino, aryl, alkoxyalkyl, alkoxycarbonyl, acrylic acid, phosphonic acid, halogen, nitro, nitrile, cyano, hydroxyl, epoxy, silane, siloxane, alcohol, benzyl, carboxylate, ether, ethercarboxylate, urethane, and R 8 and R 9 , R 9 and R 10 , and R 10 and R 11 at least one of the following may be joined to form an alkenylene chain completing a 5- or 6-membered aromatic ring, which may optionally contain one or more divalent nitrogen or oxygen atoms.

[0158] In some embodiments, the fused polycyclic heteroaromatic monomer has a formula selected from the group consisting of V(a), V(b), V(C), V(d), V(e), V(f), V(g), V(h), V(i), VG), and V(k): [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] During the ceremony Q is NH, and T is the same or different in each occurrence, NR 6 , O, SiR 6 2, and PR 6 is selected from Y is N, and R 6 is hydrogen or alkyl.

[0159] The fused polycyclic heteroaromatic monomer may be further substituted with a group selected from alkyl, heteroalkyl, alcohol, benzyl, carboxylate, ether, ethercarboxylate, and urethane. In some embodiments, the substituents are fluorinated. In some embodiments, the substituents are fully fluorinated.

[0160] In some embodiments, polycyclic heteroaromatic monomers contemplated for use in forming the polymers in the novel compositions include Formula VI: [ka] During the ceremony, Q is NR 6 and T is NR 6 , O, SiR 6 2, and PR 6 is selected from E is selected from alkenylene, arylene, and heteroarylene; R 6 is hydrogen or alkyl; R 12 are the same or different at each occurrence and are selected from hydrogen, alkyl, alkenyl, alkoxy, alkanoyl, aryloxy, alkylaryl, arylalkyl, amino, alkylamino, dialkylamino, aryl, alkoxyalkyl, arylsulfinyl, alkoxycarbonyl, arylsulfonyl, acrylic, phosphonic, halogen, nitro, nitrile, cyano, hydroxyl, epoxy, silane, siloxane, alcohol, benzyl, carboxylate, ether, ethercarboxylate, urethane, or Both R 12 The groups may be joined together to form an alkylene or alkenylene chain completing a 3-, 4-, 5-, 6-, or 7-membered aromatic or alicyclic ring, which may optionally contain one or more divalent nitrogen or oxygen atoms.

[0161] In some embodiments, the conductive polymer is a copolymer of a precursor monomer and at least one second monomer. Any type of second monomer can be used as long as it does not adversely affect the desired properties of the copolymer. In some embodiments, the second monomer comprises 50% or less of the polymer based on the total number of monomer units. In some embodiments, the second monomer comprises 30% or less based on the total number of monomer units. In some embodiments, the second monomer comprises 10% or less based on the total number of monomer units.

[0162] Exemplary types of second monomers include, but are not limited to, alkenyls, alkynyls, arylenes, and heteroarylenes. Examples of second monomers include, but are not limited to, fluorenes, oxadiazoles, phenylenevinylenes, phenyleneethynylenes, pyridines, diazines, and triazines, all of which may be further substituted.

[0163] In some embodiments, copolymers are made by first forming an intermediate precursor monomer having the structure ABC, where A and C represent precursor monomers, which may be the same or different, and B represents a second monomer. ABC intermediate precursor monomers can be prepared using standard organic synthesis techniques, such as Yamamoto, Stille, Grignard metathesis, Suzuki, and Negishi coupling. Copolymers are then formed by oxidative polymerization of the intermediate precursor monomer alone or with one or more additional precursor monomers.

[0164] Conductive polymers are typically formed by oxidative polymerization of precursor monomers in the presence of an acid.

[0165] The acid is preferably a sulfonic acid, a carboxylic acid, or a mixture thereof, with sulfonic acids being especially preferred.

[0166] The acid may be a polymeric acid selected from a polymeric sulfonic acid, a polymeric phosphoric acid, a polymeric phosphonic acid, a polymeric carboxylic acid, a polymeric acrylic acid, or mixtures thereof.

[0167] Suitable polymeric acids include polymeric styrene sulfonic acids.

[0168] The polymeric acid may be fluorinated and may be a fluorinated acid polymer as described herein.

[0169] The acid may be non-polymeric and is selected from a sulfonic acid, a carboxylic acid, or a mixture thereof.

[0170] Suitable non-polymeric acids include aromatic sulfonic acids, aromatic carboxylic acids, and mixtures thereof, with aromatic sulfonic acids being especially preferred.

[0171] Suitable aromatic sulfonic acids include benzenesulfonic acid or toluenesulfonic acid.

[0172] Preferably, the conductive polymer is formed in the presence of toluenesulfonic acid.

[0173] OER, ORR, HER, HRR catalyst materials Various types of catalytic materials are known for use in fuel cells, as outlined, for example, in X. Wang et al., Adv. Energy Mater., 2017, 7, 1700544 and C. Zhang et al., Front. Energy., 2017, 11, 268-285 and N. Alonso-Vante et al., catalysts, 2018, 8, 559.

[0174] In some embodiments, bifunctional catalysts can be used in fuel cells. A bifunctional catalyst is a catalyst that has the ability to catalyze two different types of reactions.

[0175] In some cases, the ORR and OER may be catalyzed by the same bifunctional catalyst.

[0176] In some cases, the OER and HER may be catalyzed by the same bifunctional catalyst.

[0177] In instances where a bifunctional catalyst is used, a heterojunction may be used to separate positive and negative charges within the organic material.

[0178] Noble metal-based electrocatalysts (Pt, Ir, and Ru-based) are well known to catalyze the ORR, OER, and HER reactions.

[0179] Platinum group metals are known for their use as electrocatalysts, and are most commonly used as platinum in electrocatalysts. However, concerns about the durability of platinum use around the world have led to research into novel platinum group metal alloy nanoparticles supported on conductive substrates such as carbon, carbon black, oxides, single-walled carbon nanotubes, and carbon nanofibers.

[0180] Such platinum group metal alloys can be described as Pt-M (where M=3d transition metal) alloy nanoparticles, for example, where M is one or more of Ni, Co, Fe, Cu, Pd, Rh, Ti, V, Cr, Mo, W, and Re. For example, PtNi3, Pt x Co (where x=2, 3, 5, 7, and 9), Pt3Cu, PtCu, and PtCu3.

[0181] In some cases, ternary Pt-based systems may also be suitable catalysts, such as those that may be described as Pt-MN, where M is as defined above and N is Fe, Cu, Ni, or Co, such as Pt2CuNi, Pt3CoNi, Pt3FeNi, and Pt3FeCo.

[0182] Transition metal-based catalysts are also known as suitable electrocatalysts for ORR, OER, and HER, such as Ti, V, Mn, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, or mixtures thereof based catalysts, such as Mn oxide, Co oxide, Ni oxide, and Fe oxide.

[0183] Suitable cobalt-based catalysts include, but are not limited to, cobalt oxide, cobalt phosphide, cobalt halides, cobalt nitrate, cobalt chalcogenides (sulfides and selenides), Co-containing layered double hydroxides, Co-NC, Co-based single atoms, Co-MOFs (metal-organic frameworks), cobalt carboxylates, Co-Nx / C, and composites thereof.

[0184] Examples of cobalt sulfides include CoS, CoS2, Co9S8, and Co3S4.

[0185] Examples of cobalt oxide include Co3O4 and CoO.

[0186] Examples of cobalt phosphides include CoP, Co2P, and Co3P2.

[0187] Examples of cobalt carboxylates include cobalt acetate and cobalt oxalate.

[0188] Preferred cobalt salts have a crystallite size of less than 0.7 nm, preferably less than 0.6 nm.

[0189] Such cobalt salts include cobalt nitrate, cobalt chloride, cobalt oxalate, and cobalt acetate. Cobalt nitrate and cobalt acetate have crystal sizes of less than 0.6 nm and are preferred, with cobalt acetate being especially preferred.

[0190] Such cobalt materials may be mixed, doped, or combined with other materials, such as carbon materials.

[0191] The catalytic metals can be supported on a conductive substrate, for example, on conductive carbonaceous materials such as carbon black, Vulcan-XC-72, nitrogen doped carbon nanotubes, carbon nanowebs, graphene and reduced graphene oxide.

[0192] Catalytic metals supported on (N-doped) carbon nanofoam materials according to the present disclosure have been developed and form part of the composite catalytic materials disclosed herein.

[0193] In some cases, cobalt phosphide (CoP) nanoparticles embedded in amorphous cobalt oxide (CoOx) nanoplates (CoP@a-CoOx plates) with a heterojunction-like structure may be used.

[0194] In such instances, CoP@a-CoOx plates can be synthesized by combining solvothermal and low-temperature phosphorylation pathways, such methods being known in the art.

[0195] For example, CoP@a-CoOx plates can be synthesized from CoCo-layered double hydroxide precursors (CoCo-LDH plates).

[0196] CoCo-LDH plates can be prepared via a solvothermal route. For example, a cobalt salt, such as cobalt acetate, can be added to a suitable solvent, such as ethylene glycol, and dissolved by sonication if necessary. The solution can then be heated for a sufficient time and then cooled, for example at about 200° C. for about 5 hours and then cooled to room temperature. The resulting precipitate can be recovered, for example, by suction filtration and washing with deionized water and ethanol. The subsequent filtrate can then be dried, for example, at 60° C. overnight / about 12 hours.

[0197] The CoCo-LDH can then be phosphorylated using phosphorus vapor, for example from sodium hypophosphite (NaH2PO2). In an exemplary method, the CoCO-LDH can be introduced into a tubular reactor with NaH2PO2 in a mass ratio of NaH2PO2:CoCo-LDH 10:1 under an argon atmosphere, and then heated to 300°C at a heating rate of 1°C / min in a static argon atmosphere. Heating at 300°C can be maintained for 1 hour.

[0198] Those skilled in the art will appreciate that the above catalysts may have different morphologies. The catalysts may be microstructured, such as microparticles, or nanostructured, such as nanoparticles, nanospheres, nanowires, nanosheets, nanorods, core-shell and hollow structures.

[0199] As used herein, the term "nanostructure" refers to a structure having at least one dimension less than or equal to 1000 nm, and preferably all three dimensions less than or equal to 1000 nm.

[0200] In another embodiment, the nanostructures have an average size of about 1 nm to about 200 nm.

[0201] In some cases, the nanostructures have an average size of about 20 nm to about 100 nm, about 30 nm to about 80 nm, or about 30 nm to about 50 nm.

[0202] Those of skill in the art will understand that the term nanostructure average size, as used herein, refers to the diameter at the largest point of the nanostructure and can be measured using techniques well known to those of skill in the art, such as electron microscopy techniques, such as scanning electron microscopy (SEM) or transmission electron microscopy (TEM), or dynamic light scattering (DLS) techniques, as known to those of skill in the art.

[0203] Preferably, the catalytic material promotes a four-electron oxygen reduction reaction.

[0204] When reducing oxygen in an acidic environment, there are two potential pathways: a four-electron pathway, or a two-electron pathway involving two two-electron steps. Schematics of the two pathways are shown below. (Formula 1) Four-electron pathway: O2+4H + +4e - →2H2O Two-electron pathway: (Formula 2) O2+2H + +2e - →H2O2 (Formula 3) H2O2+2H + +2e - →2H2O

[0205] As shown in the reaction scheme above, hydrogen peroxide (H2O2) is an intermediate in the two-electron pathway. Hydrogen peroxide can degrade fuel cell materials, limiting efficiency and lifetime. In particular, membranes are particularly sensitive to the presence of hydrogen peroxide in the system.

[0206] Therefore, it is preferable to provide a catalyst that promotes a direct (one-step) four-electron reduction reaction to minimize the amount of hydrogen peroxide produced.

[0207] Examples of catalytic materials that promote the direct four-electron pathway are Co, Fe, and Ni based catalytic materials, such as metallic Co, Fe, Ni, alloys of Co, Fe, Ni, oxides of Co, Fe, Ni, or mixtures thereof, preferably where Fe is present, Fe is in the 3+ oxidation state.

[0208] Preferred catalytic materials that promote the direct four-electron pathway are selected from Co, Ni-Fe alloys, NiO2, or mixtures thereof.

[0209] Fluorinated Acid Polymers The fluorinated acid polymer can be any polymer that is fluorinated and has acidic groups with acidic protons. The acidic groups provide ionizable protons. In some embodiments, the acidic protons have a pKa of less than 3. In some embodiments, the acidic protons have a pKa of less than 0. In some embodiments, the acidic protons have a pKa of less than -5.

[0210] The acidic groups can be attached directly to the polymer backbone or can be attached to side chains on the polymer backbone.

[0211] Examples of acidic groups include, but are not limited to, carboxylic acid groups, sulfonic acid groups, sulfonimide groups, phosphoric acid groups, phosphonic acid groups, and combinations thereof. The acidic groups may all be the same, or a polymer may have more than one type of acidic group.

[0212] In some embodiments, the acidic groups are selected from the group consisting of sulfonic acid groups, sulfonimide groups, and combinations thereof.

[0213] In some embodiments, the fluorinated acid polymer has at least about 50%, typically at least about 75%, and preferably at least about 90% of the total number of halogen and hydrogen atoms in the polymer are fluorine atoms.

[0214] A fluorinated acid polymer in which at least about 90% of the total number of halogen and hydrogen atoms in the polymer are fluorine atoms is described as "highly fluorinated."

[0215] Preferably, the fluorinated acid polymer is perfluorinated.

[0216] Examples of suitable polymer backbones include, but are not limited to, polyolefins, polyacrylates, polymethacrylates, polyimides, polyamides, polyaramids, polyacrylamides, polystyrenes, and copolymers thereof, all of which are typically highly fluorinated, and preferably fully fluorinated.

[0217] In one embodiment, the acidic group is a sulfonic acid group or a sulfonimide group.

[0218] The formula for the sulfonimide group is: -SO2-NH-SO2-R Here, R is an alkyl group.

[0219] In some embodiments, the acidic groups are on fluorinated side chains. The fluorinated side chains can be selected from alkyl groups, alkoxy groups, amide groups, ether groups, and combinations thereof, all of which are preferably fully fluorinated.

[0220] In some embodiments, the fluorinated acid polymer has a highly fluorinated olefin backbone with pendant highly fluorinated alkyl sulfonate, highly fluorinated ether sulfonate, highly fluorinated ester sulfonate, or highly fluorinated ether sulfonimide groups.

[0221] In some embodiments, the fluorinated acid polymer is a perfluoroolefin with perfluoroethersulfonic acid side chains.

[0222] In some embodiments, the polymer is a copolymer of 1,1-difluoroethylene and 2-(1,1-difluoro-2-(trifluoromethyl)allyloxy)-1,1,2,2-tetrafluoroethanesulfonic acid.

[0223] In some embodiments, the polymer is a copolymer of ethylene and 2-(2-(1,2,2-trifluorovinyloxy)-1,1,2,3,3,3-hexafluoropropoxy)-1,1,2,2-tetrafluoroethanesulfonic acid. These copolymers can be prepared as the corresponding sulfonyl fluoride polymers and then converted to the sulfonic acid form.

[0224] In some embodiments, the fluorinated acid polymer is a homopolymer or copolymer of a fluorinated partially sulfonated poly(arylene ether sulfone). The copolymer may be a block copolymer.

[0225] In one embodiment, the fluorinated acid polymer is a sulfonimide polymer having Formula VII: [ka] During the ceremony, R f is selected from highly fluorinated alkylenes, highly fluorinated heteroalkylenes, highly fluorinated arylenes, and highly fluorinated heteroarylenes, optionally substituted with one or more ether oxygens; and n is at least 4.

[0226] In some embodiments of Formula VII, R f is a perfluoroalkyl group such as a perfluorobutyl group.

[0227] In some embodiments, R f contains ether oxygen.

[0228] In some embodiments, n is greater than 10.

[0229] In one embodiment, the fluorinated acid polymer comprises a highly fluorinated polymer backbone and side chains having formula VIII: [ka] During the ceremony, R 15 is a highly fluorinated alkylene group or a highly fluorinated heteroalkylene group, R 16 is a highly fluorinated alkyl group or a highly fluorinated aryl group, and a is 0 or an integer of 1 to 4.

[0230] In one embodiment, the fluorinated acid polymer has formula IX: [ka] During the ceremony, Each R 16 is independently a highly fluorinated alkyl group or a highly fluorinated aryl group; each c is independently 0 or an integer from 1 to 3; and n is at least 4.

[0231] In one embodiment, the fluorinated acid polymer has the formula X: [ka] During the ceremony, Each c is independently 0 or an integer from 1 to 3; n is at least 4; R f 3 and R f 4 are independently selected from F, Cl, or a highly fluorinated alkyl group having 1 to 10 carbon atoms; a=0, 1, or 2; E 5 is selected from hydrogen or a cation such as Li, Na, or K.

[0232] In one embodiment, the fluorinated acid polymer has formula XI: [ka] During the ceremony, Each c is independently 0 or an integer from 1 to 3; n is at least 4, and E 5 is selected from hydrogen or a cation such as Li, Na, or K.

[0233] The synthesis of fluorinated acid polymers is described, for example, in A. Feiring et al., J. Fluorine Chemistry 2000, 105, 129-135; A. Feiring et al., Macromolecules 2000, 33, 9262-9271; D. D. Desmarteau, J. Fluorine Chem. 1995, 72, 203-208; A. J. Appleby et al., J. Electrochem. Soc. 1993, 140(1), 109-111; and Desmarteau, U.S. Pat. No. 5,463,005.

[0234] In some embodiments, the fluorinated acid polymer also contains repeat units derived from at least one highly fluorinated ethylenically unsaturated compound. The perfluoroolefin contains 2 to 20 carbon atoms. Representative perfluoroolefins include, but are not limited to, tetrafluoroethylene, hexafluoropropylene, perfluoro-(2,2-dimethyl-1,3-dioxole), perfluoro-(2-methylene-4-methyl-1,3-dioxolane), CF2=CFO(CF2)tCF=CF2 (where t is 1 or 2), and Rf''OCF=CF2 (where Rf'' is a saturated perfluoroalkyl group of 1 to about 10n carbon atoms).

[0235] Preferably, the comonomer is tetrafluoroethylene.

[0236] In some embodiments, the fluorinated acid polymer comprises a highly fluorinated carbon backbone and side chains represented by the formula: -(O-CF2CFR f 3 ) a -O-CF2CFR f 4 SO3E 5 During the ceremony, R f 3 and R f 4 are independently selected from F, Cl, or a highly fluorinated alkyl group having 1 to 10 carbon atoms; a=0, 1, or 2; and E 5 is selected from hydrogen or a cation such as Li, Na, or K.

[0237] In some embodiments, the fluorinated acid polymer can be a polymer disclosed in US Pat. No. 3,282,875 and US Pat. Nos. 4,358,545 and 4,940,525.

[0238] In some embodiments, the fluorinated acid polymer comprises a perfluorocarbon backbone and side chains represented by the formula: -O-CF2CF(CF3)-O-CF2CF2SO3E 5 During the ceremony, E 5 is selected from hydrogen or a cation such as Li, Na, or K.

[0239] Fluorinated acid polymers of this type are disclosed in U.S. Pat. No. 3,282,875 and can be prepared by copolymerization of tetrafluoroethylene (TFE) with the perfluorovinyl ether CF2=CF-O-CF2CF(CF3)-O-CF2CF2SO2F, perfluoro(3,6-dioxa-4-methyl-7-octene sulfonyl fluoride) (PDMOF), followed by hydrolysis of the sulfonyl fluoride groups to sulfonate groups and, if necessary, ion exchange to convert them to the desired ionic form.

[0240] An example of a polymer of the type disclosed in U.S. Pat. Nos. 4,358,545 and 4,940,525 is a polymer having the side chain -O-CF2CF2SO3E 5 Wherein, E 5 is as defined above. The polymer can be prepared by copolymerization of tetrafluoroethylene (TFE) with the perfluorovinyl ether CF2=CF-O-CF2CF2SO2F, perfluoro(3-oxa-4-pentenesulfonyl fluoride) (POPF), followed by hydrolysis and, if necessary, ion exchange.

[0241] One type of fluorinated acid polymer is commercially available as Nafion® dispersion from The Chemours Company (Wilmington, Del.). Nafion® dispersions suitable for use in the present invention include Nafion® 212.

[0242] Composite Catalyst Materials In one embodiment, A catalyst comprising a metal or metal oxide of Groups 4 to 11; a conductive material including a conductive polymer; A composite catalyst material is provided, wherein the catalyst and the conductive material are supported by a (N-doped) carbon nanofoam material.

[0243] By "comprises a metal" it is meant that the catalyst comprises a metal, but not necessarily in metallic form. For example, the catalytic metal may be present as a sulfide, phosphide, or carbide. Preferably, the metal is in metallic form.

[0244] The (N-doped) carbon nanofoam material is preferably N-doped carbon nanofoam, especially N-doped carbon nanofoam such as superstructures of coalesced N-doped carbon nanofoam particles as described above.

[0245] The (N-doped) carbon nanofoam material provides a scaffold for the catalytic and conductive materials, acting as a structural framework to support the catalytic and conductive materials.

[0246] The catalyst and the conductive material are supported by the (N-doped) carbon nanofoam material. This structure can be achieved by depositing the conductive material and catalyst onto the (N-doped) carbon nanofoam material and coating the (N-doped) carbon nanofoam material with the conductive material and catalyst.

[0247] Preferably, the (N-doped) carbon nanofoam material is enveloped in the conductive material. In other words, the (N-doped) carbon nanofoam material is embedded in and surrounded by the conductive material. This structure allows the conductive material to provide a conductive connection to the catalyst particles, facilitating the transfer of electrons to and from the catalyst. Typically, the catalyst particles are co-deposited with the conductive material such that the conductive material provides a conductive web between the catalyst particles.

[0248] The catalyst and conductive material can be deposited on the (N-doped) carbon nanofoam material in a variety of ways, either separately or in the same step. The catalyst can be deposited either before or after the conductive material.

[0249] The catalyst is typically deposited by the polyol method, which is well known in the art and involves suspending the metal precursor in a polyol, such as ethylene glycol, and heating the suspension.

[0250] The metal may be in the form of any of the OER, ORR, HER or HRR catalysts identified herein and is selected to tailor the catalyst to the particular reactivity required.

[0251] Preferred catalytic metals are selected from Ti, V, Mn, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, or mixtures thereof, more preferably Co, Fe, Ni, or mixtures thereof.

[0252] For example, the catalytic material may be metallic Co, Fe, Ni, alloys of Co, Fe, Ni, oxides of Co, Fe, Ni, or mixtures thereof, preferably where Fe is present, Fe is in the 3+ oxidation state.

[0253] Preferably, the catalyst material promotes a four-electron redox reaction (i.e., the reaction in which dioxygen is reduced by reaction with protons and electrons to form water, or vice versa, without producing hydrogen peroxide) and is selected from the preferred four-electron catalysts discussed above. Thus, the fuel cells of the present disclosure produce low levels of hydrogen peroxide during use.

[0254] Preferred catalysts are Co, CoP@a-CoOx, CoP, MoS2, IrO x , Pt, WC, Ni, NiFe, V2O5, Ti, and Nb.

[0255] Particularly preferred catalysts are selected from Co, CoP@a-CoOx, CoP, Ni, NiFe.

[0256] For OER and ORR catalysts in water-based fuel cells, cobalt is particularly preferred.

[0257] The catalytic metals are typically supported on the (N-doped) carbon nanofoam material as nanoparticles, preferably with small crystallite size.

[0258] Nanoparticles have a much higher surface area to volume ratio, making the catalytic metals more active when presented in this form. Additionally, the smaller crystallite size leads to higher internal stresses within the crystals, making the surface more active.

[0259] For example, in the case of cobalt, the crystallite size of the catalytic metal is preferably less than 0.7 nm, more preferably less than 0.6 nm.

[0260] Other metal atoms are large in size and therefore can maintain high catalytic activity even when the crystallite size is large.

[0261] When the composite catalyst material is used as an OER catalyst in water-based fuel cells, it is preferred that the cobalt comprises cobalt phosphide, in particular CoP@a-CoOx (cobalt phosphide nanoparticles embedded in amorphous cobalt oxide nanoplatelets with a heterojunction-like structure).

[0262] For ORR catalysts in water-based fuel cells, cobalt metal or cobalt salts can be used, especially cobalt salts with crystallite sizes less than 0.7 nm, preferably less than 0.6 nm.

[0263] Suitable cobalt salts include those mentioned above, especially cobalt nitrate or cobalt acetate.

[0264] The catalytic composite typically contains 1 to 20 wt % catalytic metal (ie, total metals from Groups 4 to 11), preferably 5 to 15 wt % catalytic metal.

[0265] The amount of catalytic metal can be calculated using the following formula:

number

number

[0266] It represents the percentage of the catalytic metal compound that is actually catalytic metal.

[0267] In electronic devices such as fuel cells, the composite catalyst material can be deposited onto an electrode such that the conductive material provides an electrical connection between the catalyst and the electrode.

[0268] The conductive material includes a conductive polymer, which may be any of the conductive polymers described herein.

[0269] In some embodiments, the conductive polymer is a poly-N-aryl polymer.

[0270] In some embodiments, the conductive polymer is selected from the group consisting of polypyrrole, polyaniline, and combinations thereof.

[0271] In some embodiments, the conductive polymer is selected from the group consisting of unsubstituted polypyrrole, unsubstituted polyaniline, and combinations thereof.

[0272] The conductive polymer is preferably selected from polypyrrole, polyaniline, and mixtures thereof.

[0273] Preferably, the conductive polymer is a mixture of polypyrrole and polyaniline.

[0274] Preferably, the conductive polymer is formed in the presence of a non-polymeric aromatic sulfonic acid, such as toluene sulfonic acid.

[0275] The conductive polymer may be formed in the presence of the (N-doped) carbon nanofoam material, which typically results in the (N-doped) carbon nanofoam material being enveloped in the conductive polymer.

[0276] The catalyst may be directly deposited on the surface of the (N-doped) carbon nanofoam material, may be deposited on a surface of the (N-doped) carbon nanofoam material coated with a conductive material, or may be co-deposited with the conductive material on the surface of the (N-doped) carbon nanofoam material.

[0277] The conductive polymer may be partially carbonized.

[0278] "Carbonized" means converted into a carbon material by heating.

[0279] By "partially carbonized" it is meant that the conductive polymer exists in both carbonized and uncarbonized forms. A partially carbonized system may be formed by heating the system at a temperature sufficient to induce carbonization (i.e., conversion of the organic material to network carbon or graphitic deposits) for a time insufficient to cause complete carbonization.

[0280] Without wishing to be bound by theory, it is believed that when the reaction rate is fast, for example when the composite catalyst material has good electrical properties, the four-electron pathway for oxygen reduction is promoted. Therefore, it is preferable to provide a conductive polymer with good electrical properties.

[0281] The conductive polymer of the present disclosure has a resistivity of preferably 1 to 1000, preferably 1 to 500, and more preferably 1 to 250 S / cm -2 It has a conductivity of

[0282] Preferably, the composite catalyst material comprises: A catalyst comprising a metal or metal oxide of Groups 4 to 11; and a conductive material comprising a partially carbonized conductive polymer; the catalyst and the conductive material are supported by an (N-doped) carbon nanofoam material; The (N-doped) carbon nanofoam material is surrounded by a conductive material.

[0283] Because carbonization typically proceeds from the exposed surface, a partially carbonized conductive polymer typically comprises a core comprising the conductive polymer and a shell comprising the conductive carbonized material.

[0284] Therefore, preferably, the composite catalyst material comprises: A catalyst comprising a metal or metal oxide of Groups 4 to 11; a conductive material including a core including a conductive polymer and a shell including a conductive carbonized material; the catalyst and the conductive material are supported by an (N-doped) carbon nanofoam material; The (N-doped) carbon nanofoam material is surrounded by a conductive material.

[0285] Carbonization of the conductive polymer induces partial fusion of the polymer with the (N-doped) carbon nanofoam material, increasing the electrical conductivity of the catalyst material. However, complete carbonization can result in loss of electrical conductivity, believed to be due to cracks occurring during the graphite crystallization of the material, resulting in insulating gaps between the graphite plates. The residual conductive polymer, even at low levels, bridges these gaps, maintaining high electrical conductivity throughout the material.

[0286] Partial carbonization of the polymer fuses it into the (N-doped) carbon nanofoam material, improving the electrical conductivity between the bulk material and the catalytic centers.

[0287] Preferably, the composite catalyst material comprises a partially carbonized conductive polymer selected from polypyrrole, polyaniline, or a mixture thereof.

[0288] Forming partially carbonized conductive polymers from N-containing heteroaromatics such as pyrrole or aniline gives N-doped graphite platelets that contain reactive nitrogen sites similar to those in the (N-doped) carbon nanofoam materials described above, which are advantageous as they facilitate the catalytic reactions that occur in fuel cells.

[0289] The composite catalyst material may be formed by a method comprising: forming a conductive polymer by oxidative polymerization in the presence of (N-doped) carbon nanofoam material to form a polymer:(N-doped) carbon nanofoam composite; depositing a catalytic metal on the (N-doped) carbon nanofoam material; and Optionally, the method includes the step of partially carbonizing the conductive polymer.

[0290] The present disclosure also relates to a composite catalyst material formed by partially carbonizing a material, said material comprising: A catalyst comprising a metal or metal oxide of Groups 4 to 11; a conductive material including a conductive polymer; The catalyst and the conductive material are supported by an (N-doped) carbon nanofoam material.

[0291] Depositing catalytic metals onto the N-doped carbon composite typically involves co-dispersing the materials and removing the solvent. Sonication or other dispersion methods can be used to facilitate dispersion and mixing of the components.

[0292] After removal of the solvent, the resulting material may optionally be partially carbonized by heating in an inert atmosphere, for example under argon, to a temperature sufficient to decompose the conductive polymer.

[0293] Typically the material is heated to a temperature of 500° C. to 1100° C., preferably 700° C. to 900° C., most preferably 750° C. to 850° C., for 30 minutes to 4 hours, preferably 1 hour to 3 hours.

[0294] The formation of conductive polymers by oxidative polymerization is well known in the art and described herein, and typically the polymerization is carried out prior to combination with the catalytic metal to ensure that the catalyst is not contaminated by the polymerization process and that the polymerization is not affected by the catalytic metal.

[0295] The conductive polymer is typically formed in the presence of a non-polymeric acid, such as a non-polymeric aromatic sulfonic acid or a non-polymeric aromatic carboxylic acid.

[0296] In one embodiment, the conductive polymer is formed in the presence of benzenesulfonic acid or toluenesulfonic acid, preferably toluenesulfonic acid.

[0297] In a preferred embodiment, the first step comprises: The method includes forming polypyrrole in the presence of (N-doped) carbon nanofoam material and polyaniline to form a polypyrrole:polyaniline:(N-doped) carbon nanofoam material composite.

[0298] Polypyrrole-based systems have been shown to exhibit excellent lifetimes as fuel cell catalysts, while polyaniline provides structural integrity to the overall catalytic composite.

[0299] In all embodiments of the composite catalyst material described herein, the (N-doped) carbon nanofoam material is preferably an N-doped carbon nanofoam material.

[0300] Preferred composite catalyst materials are selected from the group consisting of the following (all of which may be partially carbonized) (for reference, the preferred uses of the materials are given in brackets): CoP@a-CoOx:Ppy-TsOH:C nf -N x (ORR-prone bifunctional); CoP@a-CoOx:PANI:Ppy-TsOH:C nf -N x (ORR-prone bifunctional); Co:Ppy-TsOH:C nf (bifunctionality); Co:PANI:Ppy-TsOH:C nf (bifunctionality); Co:Ppy-TsOH:C nf -N x (ORR-prone bifunctional); Co:PANI:Ppy-TsOH:C nf -N x (ORR-prone bifunctional); Co:Ppy-TsOH:C nf (bifunctional with ORR propensity); Co:PANI:Ppy-TsOH:C nf (ORR-prone bifunctional); CoP:Ppy-TsOH:C nf (ORR-prone bifunctional); CoP:PANI:Ppy-TsOH:C nf (ORR-prone bifunctional); MoS2:Ppy-TsOH:C nf -N x (ORR); MoS2:PANI:Ppy-TsOH:C nf -N x (ORR); Ir0 x :Ppy-TsOH:C nf -N x (ORR); Ir0 x :PANI:Ppy-TsOH:C nf -N x (ORR); Pt:Ppy-TsOH:C nf -N x (bifunctionality); Pt:PANI:Ppy-TsOH:C nf -N x (bifunctionality); Pt-Ti-W:Ppy-TsOH:C nf -N x (OER-prone bifunctional); Pt-Ti-W:PANI:Ppy-TsOH:C nf -N x (OER-prone bifunctional); WC:Ppy-TsOH:C nf -N x (OER-prone bifunctional); WC:PANI:Ppy-TsOH:C nf -N x (OER-prone bifunctional); Ni:Ppy-TsOH:C nf -N x ; Ni:PANI:Ppy-TsOH:C nf -N x ; NiFe:Ppy-TsOH:C nf -N x ; NiFe:PANI:Ppy-TsOH:C nf -N x ; V2O5:Ppy-TsOH:C nf -N x (OER-prone bifunctional); V2O5:PANI:Ppy-TsOH:C nf -N x (OER-prone bifunctional); Ti:PPyTSOF:C nf -N x ; Ti:PANI:PPyTSOF:C nf -N x ; Nb:Ppy-TsOH:C nf -N x (OER-prone bifunctional); and Nb:PANI:Ppy-TsOH:C nf -N x (OER-prone bifunctional).

[0301] Preferred composite catalyst materials are selected from the group consisting of the following (all of which may be partially carbonized): CoP@a-CoOx:Ppy-TsOH:C nf -N x ; CoP@a-CoOx:PANI:Ppy-TsOH:C nf -N x ; Co:Ppy-TsOH:C nf -N x ; Co:PANI:Ppy-TsOH:C nf -N x ; CoP:Ppy-TsOH:C nf ; CoP:PANI:Ppy-TsOH:C nf ; MoS2:Ppy-TsOH:C nf -N x ; MoS2:PANI:Ppy-TsOH:C nf -N x ; Pt:Ppy-TsOH:C nf -N x ; Pt:PANI:Ppy-TsOH:C nf -N x ; Pt-Ti-W:Ppy-TsOH:C nf -N x ; Pt-Ti-W:PANI:Ppy-TsOH:C nf -N x ; WC:Ppy-TsOH:C nf -N x ; WC:PANI:Ppy-TsOH:C nf -N x ; NiFe:Ppy-TsOH:C nf -Nx ; NiFe:PANI:Ppy-TsOH:C nf -N x ; V2O5:Ppy-TsOH:C nf -N x ; V2O5:PANI:Ppy-TsOH:C nf -N x ; Nb:Ppy-TsOH:C nf -N x and Nb:PANI:Ppy-TsOH:C nf -N x .

[0302] Particularly preferred composite catalyst materials are selected from the group consisting of the following (all of which may be partially carbonized): CoP@a-CoOx:PANI:Ppy-TsOH:C nf -N x ; Co:Ppy-TsOH:C nf -N x ; Co:Ppy-TsOH:C nf ; CoP:Ppy-TsOH:C nf ; MoS2:Ppy-TsOH:C nf -N x ; Ir0 x :Ppy-TsOH:C nf -N x ; Pt:Ppy-TsOH:C nf -N x ; Pt-Ti-W:Ppy-TsOH:C nf -N x ; WC:Ppy-TsOH:C nf -N x ; Ni:Ppy-TsOH:C nf -N x ; NiFe:Ppy-TsOH:C nf -Nx ; V2O5:Ppy-TsOH:C nf -N x and Nb:Ppy-TsOH:C nf -N x .

[0303] Preferred composite catalyst materials for the ORR catalyst are selected from the group consisting of the following (all of which may be partially carbonized): CoP@a-CoOx:Ppy-TsOH:C nf -N x ; CoP@a-CoOx:PANI:Ppy-TsOH:C nf -N x ; Co:Ppy-TsOH:C nf -N x ; Co:PANI:Ppy-TsOH:C nf -N x ; Co:Ppy-TsOH:C nf ; Co:PANI:Ppy-TsOH:C nf ; CoP:Ppy-TsOH:C nf ; CoP:PANI:Ppy-TsOH:C nf ; MoS2:Ppy-TsOH:C nf -N x ; MoS2:PANI:Ppy-TsOH:C nf -N x ; Ir0 x :Ppy-TsOH:C nf -N x and Ir0 x :PANI:Ppy-TsOH:C nf -N x .

[0304] Preferred composite catalyst materials for OER catalysts are selected from the group consisting of the following (any of which may be partially carbonized): Pt:Ppy-TsOH:C nf -N x ; Pt:PANI:Ppy-TsOH:C nf -N x ; Pt-Ti-W:Ppy-TsOH:C nf -N x ; Pt-Ti-W:PANI:Ppy-TsOH:C nf -N x ; WC:Ppy-TsOH:C nf -N x ; WC:PANI:Ppy-TsOH:C nf -N x ; V2O5:Ppy-TsOH:C nf -N x ; V2O5:PANI:Ppy-TsOH:C nf -N x ; Nb:Ppy-TsOH:C nf -N x and Nb:PANI:Ppy-TsOH:C nf -N x .

[0305] As used above: PANI refers to polyaniline. Ppy represents polypyrrole. TsOH refers to toluenesulfonic acid. C nf -N x denotes an (N-doped) carbon nanofoam material; and C nf indicates a carbon nanofoam material.

[0306] Figures 6a and 6b show the CoP@a-CoOx:PANI:Ppy-TsOH:C nf -N x TEM images of ORR composites are shown.

[0307] 7a and 7b show the TEM images of the PANI:polypyrrole-TsOH:(N-doped) carbon nanofoam material:cobalt OER composite.

[0308] The composite catalyst material may be applied to a suitable electrode, such as the porous first electrode described above.

[0309] Suitable methods for applying the composite catalyst material include either spin coating, dip coating, drop casting, spraying, or brush coating a dispersion of the composite onto the electrode surface.

[0310] The electrode itself typically has a large surface area, resulting in a non-uniform surface texture, and with this in mind, spin coating is preferred as it typically provides a thin, uniform coating on the electrode surface.

[0311] Optionally, the composite catalytic material can be applied to the surface of the electrode prior to carbonization, and the partial carbonization step is carried out in situ on the electrode.

[0312] Optionally, the composite catalyst material may be applied as a dispersion with a binder to improve adhesion to the surface. Suitable binders include fluorinated acid polymers as described herein. When present, binders are typically used at less than 5 wt%, preferably less than 3 wt%.

[0313] The composite catalyst material preferably comprises a superstructure of coalesced (N-doped) carbon nanofoam particles. In such an embodiment, the overall structure of the composite catalyst material resembles a superstructure of coalesced particles, said particles preferably having a diameter of 0.005-25 μm, e.g., 0.01-15 μm, 0.01-5 μm, or 0.01-2 μm.

[0314] Smaller particles are preferred as they provide a larger surface area. In a preferred embodiment, the composite catalyst material has a superstructure of coalesced particles with diameters of 0.01-1 μm, preferably 0.01-0.5 μm, preferably 0.01-0.2 μm.

[0315] The diameter of the particle superstructure can be measured by SEM. Typically, such processes measure the largest dimension of the particle.

[0316] In one embodiment, the composite catalyst material has a superstructure of coalesced particles, said superstructure having a tortuous path of open pores that is at least 3 times the average diameter of the individual particles, preferably at least 5 times the average diameter of the individual particles, for example 5 to 100 times, preferably 5 to 50 times the average diameter of the individual particles.

[0317] The composite catalyst material is typically 50 to 2500 m 2 / g, preferably 50 to 2000m 2 / g, preferably 50 to 1800m 2 / g, preferably 50 to 1500m 2 / g, preferably 50 to 1200m 2 / g, preferably 50 to 800m 2 / g surface area.

[0318] The surface area can be measured, for example, by BET isotherm at 77K using nitrogen.

[0319] The composite catalyst material is typically characterized by a minimum overpotential of 10 mV, preferably 10-100 mV, more preferably 15-90 mV.

[0320] The composite catalyst material typically has a conductivity of 1 to 1000, preferably 1 to 500, and more preferably 1 to 250 S / cm -2 Conductivity (S / cm -2 )

[0321] Measurement protocol Pore ​​size calculation To calculate the pore diameter below the micropore level, we used the protocol proposed by Kawazoe et al., J. Chem. Eng. Japan, 16(6), 1983, 470-475.

[0322] The above protocol describes how to calculate the effective pore size distribution from the adsorption isotherm. The calculation of the pore size distribution was performed from the N2 isotherm at 77 K.

[0323] To measure the N2 isotherm at liquid N2 temperature, a sample (approximately 0.3 g) was placed in a sample holder and heated to 200 °C and 10 -5 Torr (1.33×10 -3 The mixture was degassed at a pressure of 1.33x10 Pa for at least 48 hours. A Cahn electronic balance allowed for highly accurate mass measurements. Pressure measurements were performed using a ULVAC ionization vacuum gauge and an MKS Baratron sensor (pressure range 1.33x10 -6 ~6.65x10 -1 Pa;1.33x10 -1 ~10 5 Pa).

[0324] To calculate the pore volume above 1.5 nm, we used the following protocol: Dollimore, D. and GR Heal et al., J. AppL Chem., 14, 1964, 109-114.

[0325] The above protocol describes how to calculate pore size distributions from adsorption isotherms on porous solids.

[0326] Here, the total amount of nitrogen taken up at a pressure of 1 atm and a temperature of 77 K gave the total pore volume. For a cylindrical pore model, the total pore volume was calculated using the following equation: 1 / 4*pi*d*d*l, During the ceremony, d is the average pore diameter, l is the total length of the pore.

[0327] If the BET surface area measures the total surface area of ​​the pores, then the BET surface area S(BET) = pi*d*l. The l was removed from the two equations and the average diameter d was calculated.

[0328] The Barrett-Joiner-Halenda (BJH) procedure assumes capillary condensation of liquid nitrogen in the pores and calculates the pore size distribution from the amount of nitrogen taken up at a given relative pressure and the relative pressure of the adsorption isotherm considering the adsorbed layer of nitrogen and the capillary condensed nitrogen. The adsorption and desorption branches result in different pore size distributions. Therefore, the desorption branch was usually used.

[0329] surface area The samples were treated at elevated temperature (120°C) and reduced pressure for at least 8 hours prior to nitrogen sorption to remove any bound gases and adsorbed water from the material.

[0330] N2 sorption analysis can be performed at 77 K using a Belsorp Mini (Bel Japan, Inc.) apparatus, with the liquid gas for each test, and the surface area calculated according to the Brunauer-Emmett-Teller (BET) theory using the sorption data.

[0331] Calculating the density of carbon nanofoam The following method was used:

[0332] Displacement density method: Using water as the displacement medium, density is calculated using the formula D=m / v (mass divided by volume) at 22°C and 1 atm pressure.

[0333] The TAP density method is explained as follows: · International Pharmacopoeia, s.3.6. Bulk Density and Tapped Density of Powders, QAS11_450 FINAL (revised March 2012). Tapped density is the increased bulk density obtained after mechanically tapping a container containing a powder sample.

[0334] Here, tap density is obtained by mechanically tapping the graduated cylinder containing the sample until little further volume change is observed. Tapping can be performed using a variety of methods. Tap density is calculated as the mass of the powder divided by the final volume.

[0335] The average value of the two measurement methods was then obtained.

[0336] Conductivity of ground material samples The material samples were prepared using spin coating, in a similar manner to the preparation steps for making the electrodes: silver foil in a solution containing the material sample and 5% binder addition.

[0337] If the resistance of the material sample was in the kilohms or greater, a two-point probe was used.

[0338] The spin-coated film is mounted on a metal sample holder and a vacuum is applied inside to remove moisture.

[0339] Two-point and four-point probe tests are available.

[0340] The measured conductivity of the samples was on average between 0.4 S / cm and 100 S / cm, depending on the layer thickness and conductivity of the carbon support used.

[0341] Determining the concentration of conductive polymers in sample materials One method for measuring the conductive polymer concentration in a sample material involves solvating the sample material in a suitable solvent. The solubility of polypyrrole (PPy) is highly inhibited and is virtually insoluble due to the extensive crosslinking of the polymer backbone. Neutral PPy is generally considered insoluble, but it can swell when exposed to some solvents. After swelling, the PPy can be doped with charge compensating anions (e.g., OH-) in either acidic or basic media. After this doping, the doped PPy can be dissolved in several solvents, such as chloroform, dimethyl sulfoxide (DMSO), m-cresol, N-methyl-2-pyrrolidone (NMP), and tetrahydrofuran (THF).

[0342] Alternative methods include using Raman spectroscopy, X-ray diffraction spectroscopy, and infrared spectroscopy to confirm the presence of polymer chains within the sample material, which we have had access to through the UThent Materials Science Institute.

[0343] Preferences, options, and embodiments of a given aspect, feature, or parameter of the invention should be considered as disclosed in combination with all preferences, options, and embodiments of all other aspects, features, and parameters of the invention, unless the context dictates otherwise. Embodiments and features of the invention are also outlined in the following sections.

[0344] A1. A (N-doped) carbon nanofoam material comprising a superstructure of coalesced N-doped carbon nanofoam particles, said particles having a diameter between 0.005 μm and 25 μm.

[0345] A2. The (N-doped) carbon nanofoam material according to paragraph A1, wherein the carbon nanofoam particles have a diameter of 0.01-15 μm.

[0346] A3. The (N-doped) carbon nanofoam material according to paragraph A1 or A2, wherein the carbon nanofoam particles have a diameter of 0.01-5 μm.

[0347] A4. The (N-doped) carbon nanofoam material according to any one of paragraphs A1 to A3, wherein the carbon nanofoam particles have a diameter of 0.01 to 2 μm.

[0348] A5. The (N-doped) carbon nanofoam material according to any one of paragraphs A1 to A4, wherein the carbon nanofoam particles are mesoporous.

[0349] A6. The (N-doped) carbon nanofoam material according to any one of paragraphs A1 to A5, wherein the material has a superstructure of coalesced N-doped carbon nanofoam particles, said superstructure having a tortuous path of open pores at least three times the average diameter of the nanofoam particles.

[0350] A7. The (N-doped) carbon nanofoam material according to any one of items A1 to A6, wherein the open pores of the superstructure have an average pore size of 10 to 100 μm.

[0351] A8. The (N-doped) carbon nanofoam material according to item A7, wherein the open pores of the superstructure have an average pore size of 0.2-2 μm.

[0352] A9. The density of the material is 300mg / cm 3 The (N-doped) carbon nanofoam material according to any one of paragraphs A1 to A8, wherein

[0353] A10. The density of the material is 50-200mg / cm 3 The (N-doped) carbon nanofoam material according to item A9, wherein

[0354] A11. The density of the material is 50-150mg / cm 3 The (N-doped) carbon nanofoam material according to item A10, wherein

[0355] A12. The (N-doped) carbon nanofoam material according to any one of paragraphs A1 to A11, wherein the N content of the N-doped carbon nanofoam is 0.1-8 wt%.

[0356] A13. The (N-doped) carbon nanofoam material according to any one of paragraphs A1 to A11, wherein the N-content of the N-doped carbon nanofoam is 1-5 wt%.

[0357] A14.N-doped carbon nanofoam is 200-3500m 2 The (N-doped) carbon nanofoam material according to any one of paragraphs A1 to A13, having a surface area of ​​100 nm to 150 nm / g.

[0358] A15.N-doped carbon nanofoam is 1000~2000m 2The (N-doped) carbon nanofoam material according to any one of paragraphs A1 to A13, having a surface area of ​​100 nm to 150 nm / g.

[0359] A16.(N-doped) carbon nanofoam material is 1200~1800m 2 The (N-doped) carbon nanofoam material according to any one of paragraphs A1 to A13, having a surface area of ​​100 nm to 150 nm / g.

[0360] A17. The (N-doped) carbon nanofoam material according to any one of paragraphs A1 to A16, wherein the carbon nanofoam is an N-doped carbon nanofoam material.

[0361] B1. A method for forming an (N-doped) carbon nanofoam material, comprising: i. forming a mixture of sugar, water, and a hydrocarbon mediator; ii. heating the mixture to form carbon nanofoam; iii. Optionally, heating the carbon nanofoam in an acidic nitrogen source (eg, nitric acid) to form N-doped carbon nanofoam.

[0362] B2. The method according to claim B1, wherein the sugar is one or more monosaccharides, disaccharides and / or trisaccharides.

[0363] B3. The method according to claim B2, wherein the sugar is one or more of sucrose, glucose or fructose.

[0364] B4. The method according to item B3, wherein the sugar is sucrose.

[0365] B5. A solution of sugar and water with a concentration of at least 3 mol / dm 3 The method according to any one of Items B1 to B4, wherein the concentration is

[0366] B6. A solution of sugar and water with a concentration of at least 4 mol / dm 3 The method according to any one of Items B1 to B5, wherein the concentration is

[0367] B7. A solution of sugar and water with a concentration of at least 5 mol / dm 3 The method according to any one of Items B1 to B6, wherein the concentration is

[0368] B8. The method according to any one of paragraphs B1-B7, wherein the solution is completely dissolved in water to form a sugar and water mixture.

[0369] B9. The method according to item B8, wherein the sugar is dissolved in the water by heating and vigorous stirring.

[0370] B10. The method according to item B9, wherein the sugar is dissolved in the water by heating the solution to 50°C to 85°C.

[0371] B11. The method according to item B9, wherein the sugar is dissolved in the water by heating the solution to 60°C to 80°C.

[0372] B12. The method according to any one of paragraphs B5-B11, wherein the sugar and water solution is cooled prior to adding the hydrocarbon mediator.

[0373] B13. The method of claim B12, wherein the sugar and water solution is cooled to below 50° C. before adding the hydrocarbon mediator.

[0374] B14. The method according to any one of paragraphs B1 to B13, wherein the hydrocarbon mediator is an aromatic hydrocarbon.

[0375] B15. The method according to item B14, wherein the aromatic hydrocarbon is pyrene.

[0376] B16. The method according to item B14, wherein the aromatic hydrocarbon is chrysene.

[0377] B17. The method according to item B14, wherein the aromatic hydrocarbon is benz[a]anthracene.

[0378] B18. The method according to item B14, wherein the aromatic hydrocarbon is fluoranthene.

[0379] B19. The method according to item B14, wherein the aromatic hydrocarbon is anthracene.

[0380] B20. The method according to item B14, wherein the aromatic hydrocarbon is naphthalene.

[0381] B21. The method according to item B14, wherein the aromatic hydrocarbon is benzene.

[0382] B22. The method according to item B14, wherein the aromatic hydrocarbon is hexane.

[0383] B23. The method according to any one of items B1 to B13, wherein the hydrocarbon mediator is one or more of the aromatic hydrocarbons of items B15 to B22.

[0384] B24. The method according to claim B1, wherein the hydrocarbon mediator is naphthalene and the sugar is sucrose.

[0385] B25. The method according to any one of paragraphs B1 to B24, wherein the ratio of carbohydrate mediator to sugar is 1:25,000 to 1:75,000.

[0386] B26. The method according to any one of paragraphs B1 to B25, wherein the ratio of carbohydrate mediator to sugar is 1:50,000 to 1:65,000.

[0387] B27. The method according to any one of paragraphs B1-B26, wherein step ii is carried out at a temperature and for a time sufficient to carbonize the sugar to form a particulate material.

[0388] B28. The method according to item B27, wherein step ii is carried out at a temperature of 100°C to 600°C for 30 minutes to 24 hours.

[0389] B29. The method according to item B28, wherein step ii is carried out at a temperature of 350°C to 600°C for 30 minutes to 3 hours.

[0390] B30. The method according to item B29, wherein step ii is carried out at a temperature of 100°C to 300°C for 4 hours to 12 hours.

[0391] B31. The method according to any one of paragraphs B1 to B30, wherein step ii is carried out in an inert container.

[0392] B32. The method according to any one of paragraphs B1 to B31, wherein step ii is carried out in a closed reactor.

[0393] B33. The method according to any one of paragraphs B1 to B32, wherein the nanoform produced in step ii is milled.

[0394] B34. The method according to item B33, wherein the carbon nanofoam particles coalesce to form superstructures.

[0395] B35. The method according to any one of items B33 to B34, wherein the carbon nanofoam particles are mesoporous.

[0396] B36. The method according to any one of paragraphs B33 to B35, wherein the carbon nanofoam particles formed in step ii have a diameter of 0.1 to 25 μm.

[0397] B37. The method according to any one of paragraphs B33 to B36, wherein the carbon nanofoam particles formed in step ii have a diameter of 0.2 to 15 μm.

[0398] B38. The method according to any one of paragraphs B33 to B37, wherein the carbon nanofoam particles formed in step ii have a diameter of 0.5 to 5 μm.

[0399] B39. The method according to any one of paragraphs B33 to B38, wherein the carbon nanofoam particles formed in step ii have a diameter of 0.5 to 2 μm.

[0400] B40. The method according to any one of paragraphs B1-B39, wherein the carbon nanofoam in step iii is heated to at least 80° C. for at least 2 hours.

[0401] B41. The method according to any one of paragraphs B1 to B40, wherein the carbon nanofoam in step iii is heated to at least 90° C. for at least 4 hours.

[0402] B42. The method according to any one of paragraphs B1 to B41, wherein the carbon nanofoam in step iii is heated to 95° C. to 115° C. for at least 4 hours.

[0403] B43. The method according to any one of paragraphs B1 to B42, wherein step iii is carried out in a suitable acid-resistant pressure vessel.

[0404] B44. The acidic nitrogen source (e.g., nitric acid) used in step iii is 3 mol / dm 3 ~10mol / dm 3 The method according to any one of Items B1 to B43, wherein the concentration is

[0405] B45. The acidic nitrogen source (e.g., nitric acid) used in step iii is 4 mol / dm 3 ~8mol / dm 3 The method according to any one of Items B1 to B44, wherein the concentration is

[0406] B46. The method according to any one of items B1-B44, wherein the acidic nitrogen source is selected from nitric acid.

[0407] B47. The method according to any one of paragraphs B1 to B46, wherein the (N-doped) carbon nanofoam has an N content of 0.1 to 8 wt.%.

[0408] B48. The method according to any one of paragraphs B1 to B47, wherein the (N-doped) carbon nanofoam has an N content of 1 to 5 wt.%.

[0409] B49.(N-doped) carbon nanofoam is 1000~3500m 2 The method according to any one of items B1 to B48, having a surface area of ​​1 / g.

[0410] B50. (N-doped) carbon nanofoam is 1000-2000m 2 The method according to any one of items B1 to B49, having a surface area of ​​1 / g.

[0411] B51. A (N-doped) carbon nanofoam material obtainable by the method described in items B1 to B50.

[0412] E1. A composite catalyst material, A catalyst comprising a metal or metal oxide of Groups 4 to 11; a conductive material including a conductive polymer; A composite catalyst material, wherein the catalyst and the conductive material are supported by an (N-doped) carbon nanofoam material.

[0413] E2. The composite catalyst material according to item E1, wherein the (N-doped) carbon nanofoam material is the (N-doped) carbon nanofoam according to any one of items A1 to A17.

[0414] E3. The composite catalyst material according to item E1, wherein the (N-doped) carbon nanofoam material is a composite material according to item B51.

[0415] E4. The composite catalyst material according to any one of items E1-E3, wherein the metal is a noble metal.

[0416] E5. The composite catalytic material according to item E4, wherein the noble metal is selected from Pt, Ir, or Ru.

[0417] E6. The composite catalytic material according to item E5, wherein the precious metal is Pt.

[0418] E7. The composite catalyst material according to item E6, wherein the Pt is in the form of a Pt metal alloy described in the form Pt-M, where M=3d transition metal.

[0419] E8. The composite catalyst material according to item E7, wherein M is one or more of Ni, Co, Fe, Cu, Pd, Rh, Ti, V, Cr, Mo, W and Re.

[0420] E9. The composite catalyst material according to item E7, wherein the Pt alloy is PtNi3.

[0421] E10.Pt alloy is Pt x The composite catalyst material according to item E7, wherein X is 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, and 0.1.

[0422] E11. The composite catalytic material according to item E7, wherein the Pt alloy is Pt3Cu.

[0423] E12. The composite catalytic material according to item E7, wherein the Pt alloy is PtCu.

[0424] E13. The composite catalytic material according to item E7, wherein the Pt alloy is PtCu3.

[0425] E14. The composite catalyst material according to item E6, wherein Pt is in the form of a ternary platinum-based system described in the form Pt-MN, where M is one or more of Ni, Co, Fe, Cu, Pd, Rh, Ti, V, Cr, Mo, W, Re, and N is Fe, Cu, Ni or Co.

[0426] E15. The composite catalyst material according to item E14, wherein the ternary platinum-based system is Pt2CuNi.

[0427] E16. The composite catalyst material according to item E14, wherein the ternary platinum-based system is Pt3CoNi.

[0428] E17. The composite catalyst material according to item E14, wherein the ternary platinum-based system is Pt3FeNi.

[0429] E18. The composite catalyst material according to item E14, wherein the ternary platinum-based system is Pt3FeCo.

[0430] E19. The composite catalyst material according to any one of items E1 to E3, wherein the transition metal is selected from Ti, V, Mn, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, or a mixture thereof.

[0431] E20. The composite catalyst material according to item E19, wherein the composite catalyst material is an oxide of Mn, Co, Ni or Fe.

[0432] E21. The composite catalyst material according to item E19, wherein the composite catalyst material comprises a cobalt-based catalyst.

[0433] E22. The composite catalyst material according to item E19, wherein the cobalt-based catalyst is selected from metallic cobalt, cobalt oxide, cobalt phosphide, cobalt hydride, cobalt nitrate, cobalt chalcogenides (sulfides and selenides), Co-containing layered double hydroxides, Co-NC, Co-based single atoms, Co-MOFs (metal-organic frameworks), cobalt carboxylates, Co-Nx / C, and composites thereof.

[0434] E23. The composite catalyst material according to item E21, wherein the cobalt-based catalyst is CoS.

[0435] E24. The composite catalytic material according to item E21, wherein the cobalt-based catalyst is CoS2.

[0436] E25. The composite catalyst material according to item E21, wherein the cobalt-based catalyst is metallic cobalt.

[0437] E26. The composite catalytic material according to item E21, wherein the cobalt-based catalyst is Co3S4.

[0438] E27. The composite catalyst material according to item E21, wherein the cobalt-based catalyst is Co3O4.

[0439] E28. The composite catalytic material according to item E21, wherein the cobalt-based catalyst is CoO.

[0440] E29. The composite catalyst material according to item E21, wherein the cobalt-based catalyst is CoP.

[0441] E30. The composite catalyst material according to item E21, wherein the cobalt-based catalyst is Co2P.

[0442] E31. The composite catalytic material according to item E21, wherein the cobalt-based catalyst is Co3P2.

[0443] E32. The composite catalyst material according to item E21, wherein the cobalt-based catalyst is formed from cobalt acetate.

[0444] E33. The composite catalyst material according to item E21, wherein the cobalt-based catalyst is formed from cobalt oxalate.

[0445] E34. The composite catalyst material according to item E21, wherein the cobalt-based catalyst is formed from cobalt nitrate.

[0446] E35. The composite catalyst material according to item E21, wherein the cobalt-based catalyst is formed from cobalt chloride.

[0447] E36. The composite catalytic material according to E19, wherein the transition metal is a metal selected from the following: Co, Fe, Ni, an alloy of Co, Fe, Ni, an oxide of Co, Fe, Ni, or a mixture thereof, preferably, if Fe is present, Fe is in the 3+ oxidation state.

[0448] E37. The composite catalyst material according to any one of paragraphs E1-E36, wherein the cobalt salt has a crystallite size of less than 0.7 nm.

[0449] E38. The composite catalyst material according to any one of paragraphs E1-E37, wherein the cobalt salt has a crystallite size of less than 0.6 nm.

[0450] E39. The composite catalyst material according to any one of paragraphs E1-E38, wherein the metallic material is mixed, doped, or combined with other materials.

[0451] E40. The composite catalyst material according to item E39, wherein the other material is a carbon material.

[0452] E41. The composite catalyst material according to item E29, wherein CoP nanoparticles are embedded in amorphous cobalt oxide (CoOx) nanoplates (CoP@a-CoOx plates) having a heterojunction-like structure.

[0453] E42. The composite catalyst material according to any one of paragraphs E1-E41, wherein the catalyst is in the form of nanostructures such as nanoparticles, nanospheres, nanowires, nanosheets, nanorods, core-shell and hollow structures.

[0454] E43. The composite catalytic material according to item E42, wherein the catalyst is in the form of nanoparticles.

[0455] E44. The composite catalyst material according to item E43, wherein the nanostructures have an average size of about 1 nm to about 200 nm.

[0456] E45. The composite catalyst material according to item E43, wherein the nanostructures have an average size of about 20 nm to about 100 nm.

[0457] E46. The composite catalyst material according to item E43, wherein the nanostructures have an average size of about 30 nm to about 80 nm.

[0458] E47. The composite catalyst material according to item E43, wherein the nanostructures have an average size of about 30 nm to about 50 nm.

[0459] E48. Conductive polymers are 10 -7 The composite catalyst material of any one of paragraphs E1 to E47, having a conductivity greater than S / cm.

[0460] E49. The composite catalyst material according to any one of paragraphs E1-E48, wherein the conductive polymer is a homopolymer.

[0461] E50. The composite catalyst material according to any one of items E1-E48, wherein the conductive polymer is a copolymer.

[0462] E51. The composite catalyst material according to item E50, wherein the copolymer is made from two or more conductive precursor monomers.

[0463] E52. The composite catalyst material according to item E50, wherein the copolymer is made from a combination of one or more conductive precursor monomers and one or more non-conductive precursor monomers.

[0464] E53. The composite catalyst material according to item E51 or E52, wherein the conductive polymer is made from at least one conductive precursor monomer selected from thiophene, selenophene, tellurophene, pyrrole, aniline, and polycyclic aromatics.

[0465] E54. The composite catalyst material according to item E51 or E52, wherein the conductive polymer is a poly-N-aryl polymer.

[0466] E55. The composite catalyst material according to any one of items E51 or E52, wherein the conductive polymer is selected from unsubstituted polypyrrole, unsubstituted polyaniline, or a mixture thereof.

[0467] E56. The composite catalyst material according to item E51 or E52, wherein the conductive polymer is made from a pyrrole monomer of formula (II). [ka] In formula II, R 1 are independently selected to be the same or different at each occurrence and are selected from hydrogen, alkyl, alkenyl, alkoxy, alkanoyl, aryloxy, alkylaryl, arylalkyl, amino, alkylamino, dialkylamino, aryl, alkoxyalkyl, alkoxycarbonyl, acrylic acid, phosphonic acid, halogen, nitro, cyano, hydroxyl, epoxy, silane, siloxane, alcohol, benzyl, carboxylate, ether, ethercarboxylate, urethane, or Both R 1the groups may together form an alkylene or alkenylene chain completing a 3-, 4-, 5-, 6-, or 7-membered aromatic or alicyclic ring, which ring may optionally contain one or more divalent nitrogen or oxygen atoms; and R 2 is independently selected to be the same or different at each occurrence and is selected from hydrogen, alkyl, alkenyl, aryl, alkanoyl, alkylaryl, arylalkyl, amino, epoxy, silane, siloxane, alcohol, benzyl, carboxylate, ether, ethercarboxylate, urethane.

[0468] E57. The composite catalyst material according to item E51 or E52, wherein the conductive polymer is made from an aniline monomer of formula (III). [ka] During the ceremony, a is 0 or an integer from 1 to 4, b is an integer from 1 to 5, with the proviso that a+b=5; and R 1 are independently selected to be the same or different at each occurrence and are selected from hydrogen, alkyl, alkenyl, alkoxy, alkanoyl, aryloxy, alkylaryl, arylalkyl, amino, alkylamino, dialkylamino, aryl, alkoxyalkyl, alkoxycarbonyl, acrylic acid, phosphonic acid, halogen, nitro, cyano, hydroxyl, epoxy, silane, siloxane, alcohol, benzyl, carboxylate, ether, ethercarboxylate, urethane, or Both R 1 The groups may be joined together to form an alkylene or alkenylene chain completing a 3-, 4-, 5-, 6-, or 7-membered aromatic or alicyclic ring, which may optionally contain one or more divalent nitrogen or oxygen atoms.

[0469] E58. The composite catalyst material according to item E50 or E51, wherein the conductive polymer is made from a fused polycyclic heteroaromatic monomer.

[0470] E59. The composite catalyst material according to any one of paragraphs E1-E52, wherein the conductive polymer is selected from the group consisting of polypyrrole, polyaniline, and combinations thereof.

[0471] E60. The composite catalyst material according to any one of paragraphs E1-E52, wherein the conductive polymer is selected from polypyrrole, polyaniline, and mixtures thereof.

[0472] E61. The composite catalyst material according to any one of paragraphs E1-E52, wherein the conductive polymer is a mixture of polypyrrole and polyaniline.

[0473] E62. The composite catalyst material according to any one of paragraphs E1-E61, wherein the conductive polymer is formed in the presence of a non-polymeric aromatic sulfonic acid.

[0474] E63. The composite catalyst material according to item E62, wherein the conductive polymer is formed in the presence of toluenesulfonic acid.

[0475] E64. The composite catalyst material according to any one of paragraphs E1-E62, wherein the conductive polymer is partially carbonized.

[0476] E65.Material: A catalyst comprising a metal or metal oxide of Groups 4 to 11; and a conductive material comprising a partially carbonized conductive polymer; the catalyst and the conductive material are supported by an (N-doped) carbon nanofoam material; The composite catalyst material as described in E64, wherein the (N-doped) carbon nanofoam material is enveloped in a conductive material.

[0477] E66. The composite catalyst material according to any one of paragraphs E1-E65, wherein the conductive material comprises a core comprising a conductive polymer and a shell comprising a conductive carbonized material.

[0478] E67. The composite catalyst material according to item E66, wherein the conductive carbonized material is formed by partially carbonizing a conductive polymer.

[0479] E68. The composite catalyst material according to E64, wherein the composite catalyst material comprises a partially carbonized conductive polymer selected from polypyrrole, polyaniline, or a mixture thereof.

[0480] E69. The composite catalytic material according to any one of paragraphs E1-E68, wherein the material comprises 1-20 wt.% catalytic metal.

[0481] E70. The composite catalyst material of any one of paragraphs E1-E69, wherein the material comprises 5-15 wt.% catalytic metal.

[0482] E71. The composite catalyst material of any one of paragraphs E1-E70, wherein the (N-doped) carbon nanofoam material is enveloped by a conductive material.

[0483] E72. Previous material is 50~2500m 2 The composite catalyst material according to any one of items E1 to E71, having a surface area of ​​100 nm to 150 nm / g.

[0484] E73. Material is 50~1500m 2 The composite catalyst material according to any one of items E1 to E71, having a surface area of ​​100 nm to 150 nm / g.

[0485] E74. Material is 50~800m 2 The composite catalyst material according to any one of items E1 to E71, having a surface area of ​​100 nm to 150 nm / g.

[0486] E75. The composite catalyst material according to any one of paragraphs E1 to E74, wherein the composite catalyst material has a superstructure of coalesced particles, the diameter of said particles being between 0.005 and 25 μm.

[0487] E76. The composite catalyst material according to any one of paragraphs E1 to E75, wherein the composite catalyst material has a superstructure of coalesced particles, the diameter of said particles being between 0.01 and 15 μm.

[0488] E77. The composite catalyst material according to any one of paragraphs E1 to E76, wherein the composite catalyst material has a superstructure of coalesced particles, the diameter of said particles being between 0.01 and 2 μm.

[0489] E78. The composite catalyst material of any one of paragraphs E75-E77, wherein the superstructure has a tortuous path of open pores at least three times the average diameter of the individual particles.

[0490] E79. The composite catalyst material according to any one of items E75 to E77, wherein the superstructure has a tortuous path of open pores 5 to 50 times the average diameter of the individual particles.

[0491] E80. The composite catalyst material according to any one of paragraphs E1-E79, wherein the (N-doped) carbon nanofoam material is an N-doped carbon nanofoam material.

[0492] E81. The composite catalyst material according to any one of items E1 to E79, selected from the group consisting of the following (all of which may be partially carbonized): CoP@a-CoOx:Ppy-TsOH:C nf -N x ; CoP@a-CoOx:PANI:Ppy-TsOH:C nf -N x ; Co:Ppy-TsOH:C nf ; Co:PANI:Ppy-TsOH:C nf ; Co:Ppy-TsOH:C nf -N x ; Co:PANI:Ppy-TsOH:C nf -N x ; Co:Ppy-TsOH:C nf ; Co:PANI:Ppy-TsOH:C nf ; CoP:Ppy-TsOH:C nf ; CoP:PANI:Ppy-TsOH:C nf ; MoS2:Ppy-TsOH:C nf -N x ; MoS2:PANI:Ppy-TsOH:C nf -N x ; Ir0 x :Ppy-TsOH:C nf -N x ; Ir0 x :PANI:Ppy-TsOH:C nf -N x ; Pt:Ppy-TsOH:C nf -N x ; Pt:PANI:Ppy-TsOH:C nf -N x ; Pt-Ti-W:Ppy-TsOH:C nf -N x ; Pt-Ti-W:PANI:Ppy-TsOH:C nf -N x ; WC:Ppy-TsOH:C nf -N x ; WC:PANI:Ppy-TsOH:C nf -N x ; Ni:Ppy-TsOH:C nf -N x ; Ni:PANI:Ppy-TsOH:C nf -N x ; NiFe:Ppy-TsOH:C nf -N x ; NiFe:PANI:Ppy-TsOH:C nf -N x ; V2O5:Ppy-TsOH:C nf -N x ; V2O5:PANI:Ppy-TsOH:C nf -Nx ; Ti:PPyTSOF:C nf -N x ; Ti:PANI:PPyTSOF:C nf -N x ; Nb:Ppy-TsOH:C nf -N x and Nb:PANI:Ppy-TsOH:C nf -N x .

[0493] F1. A method for forming a composite catalyst material, comprising: (i) forming a conductive polymer by oxidative polymerization in the presence of an (N-doped) carbon nanofoam material to form a polymer:N-doped carbon nanofoam composite; (ii) depositing a catalytic metal on the (N-doped) carbon nanofoam material; (iii) optionally, partially carbonizing the conductive polymer.

[0494] F2. The method of claim F1, wherein step (ii) comprises co-dispersing the materials and removing the solvent.

[0495] F3. The method according to claim F2, wherein the co-dispersion is carried out using sonication.

[0496] F4. The method according to paragraphs F2 or F3, wherein after removal of the solvent, the resulting material can optionally be partially carbonized by heating in an inert atmosphere to a temperature sufficient to decompose the conductive polymer.

[0497] F5. The method according to item F4, wherein the inert atmosphere is an argon atmosphere.

[0498] F6. The method according to item F4 or F5, wherein the obtained material is heated at a temperature of 500°C to 1100°C.

[0499] F7. The method according to any one of items F4 to F6, wherein the obtained material is heated at a temperature between 700°C and 900°C.

[0500] F8. The method according to any one of paragraphs F4 to F7, wherein the obtained material is heated at a temperature between 750°C and 850°C.

[0501] F9. The method according to any one of paragraphs F6 to F8, wherein the resulting material is heated for 30 minutes to 4 hours.

[0502] F10. The method according to any one of paragraphs F6 to F9, wherein the resulting material is heated for 1 to 3 hours.

[0503] F11. The method of any one of paragraphs F1-F10, wherein the polymerization in step (i) is carried out prior to combining with the catalytic metal.

[0504] F12. The method of any one of paragraphs F1-F11, wherein the formation of the conductive polymer in step (i) is carried out in the presence of a non-polymeric acid.

[0505] F13. The method of claim F12, wherein the non-polymeric acid is a non-polymeric aromatic sulfonic acid.

[0506] F14. The method according to item F12, wherein the non-polymeric acid is a non-polymeric aromatic carboxylic acid.

[0507] F15. The method according to item F12, wherein the non-polymeric acid is benzenesulfonic acid.

[0508] F16. The method according to item F12, wherein the non-polymeric acid is toluenesulfonic acid.

[0509] F17. The method of any one of paragraphs F1-F16, wherein step (i) comprises forming polypyrrole in the presence of (N-doped) carbon nanofoam material and polyaniline to form a polypyrrole:polyaniline:(N-doped) carbon nanofoam material nanofoam composite.

[0510] F18. The method according to claim F17, wherein the polypyrrole:polyaniline:(N-doped) carbon nanofoam material composite is PANI:polypyrrole-TsOH:(N-doped) carbon nanofoam material:CoP@a-CoOx.

[0511] F19. The method according to claim F17, wherein the polypyrrole:polyaniline:(N-doped)carbon nanomaterial composite is PANI:polypyrrole-TsOH:(N-doped)carbon nanofoam material:cobalt.

[0512] F20. The method according to any one of items F1 to F19, wherein the composite catalyst material formed is according to any one of items E1 to E81.

[0513] F21. A composite catalyst material formed by the method of any one of paragraphs F1-F20.

[0514] G1. Use of a composite catalyst material according to any one of paragraphs E1 to E81 or F21 in an electrode of a fuel cell.

[0515] G2. Use of the composite catalytic material according to any one of paragraphs E1 to E81 or F21 for promoting a four-electron redox reaction.

[0516] G3. Use of the composite catalytic material according to any one of paragraphs E1 to E81 or F21 for promoting a direct (one-step) redox reaction of converting oxygen directly into water.

[0517] H1. A method comprising applying the composite catalyst material of any one of paragraphs E1-E81 to an electrode.

[0518] H2. The method according to claim H1, wherein the composite catalyst material is applied to the electrode by spin-coating a dispersion of the composite material onto the surface of the electrode.

[0519] H3. The method of claim H1, wherein the composite catalyst material is applied to the electrode by dip-coating a dispersion of the composite material onto the surface of the electrode.

[0520] H4. The method of claim H1, wherein the composite catalyst material is applied to the electrode by drop-casting a dispersion of the composite material onto the surface of the electrode.

[0521] H5. The method of claim H1, wherein the composite catalyst material is applied to the front electrode by spray coating a dispersion of the composite material onto the surface of the electrode.

[0522] H6. The method of claim H1, wherein the composite catalyst material is applied to the electrode by brush coating a dispersion of the composite material onto the surface of the electrode.

[0523] H7. The method according to any one of paragraphs H1-H6, wherein the composite catalyst material is applied to a surface of the electrode before carbonization and the partial carbonization step is carried out in situ on the electrode.

[0524] H8. The method of any one of paragraphs H1-H7, wherein the composite catalyst material may be applied to the electrode as a dispersion including a binder (i.e., to improve adhesion to the surface).

[0525] H9. The method of claim H8, wherein the binder is a fluorinated acid polymer.

[0526] H10. The method according to claim H9, wherein the binder is used at less than 5% by weight.

[0527] H11. The method according to claim H9, wherein the binder is used at less than 3% by weight.

[0528] K1. A fuel cell comprising the composite catalyst material according to any one of items E1 to E81 or F21.

[0529] K2. The fuel cell (100) a polymer electrolyte membrane (101) having a first electrode (102) on one side and a second electrode (103) on the opposite side, the polymer electrolyte membrane (101), the first electrode (102) and the second electrode (103) being disposed between a first plate (104) and a second plate (105); a first plate (104) disposed adjacent to the first electrode (102) and a second plate (105) disposed adjacent to the second electrode (105), the first plate facing the first electrode (102) and optionally defining, at least in part, a flow path configured to supply fluid to and receive fluid from the first electrode (102); one or more first catalyst layers located between the first plate (104) and the second plate (105), The one or more first catalyst layers include A catalyst comprising a metal or metal oxide of Groups 4 to 11; a conductive material including a conductive polymer; The catalyst and the conductive material are supported by an (N-doped) carbon nanofoam material.

[0530] K3. The fuel cell of item K2, wherein the composite catalyst material is one according to any one of items E1-E81 or F21.

[0531] K4. The fuel cell of item K3, wherein the composite catalyst material coats the first electrode.

[0532] K5. The fuel cell of item K4, wherein the composite catalyst material has a superstructure of coalesced particles, the particles having diameters between 0.01 and 2 μm, and the superstructure has a tortuous path of open pores at least three times the average diameter of the individual particles.

[0533] K6. The fuel cell of any one of paragraphs K2-K5, wherein the composite catalyst material comprises a partially carbonized conductive polymer selected from polypyrrole, polyaniline, or a mixture thereof.

[0534] K7. The fuel cell according to any one of paragraphs K2-K6, wherein the metal or metal oxide in the composite catalyst material comprises a cobalt-based catalyst.

[0535] K8. The fuel cell of item K7, wherein the metal or metal oxide in the composite catalyst material comprises metallic cobalt.

[0536] K9. The fuel cell of claim K7, wherein the metal or metal oxide in the composite catalyst material on the first electrode comprises CoP nanoparticles embedded in amorphous cobalt oxide (CoOx) nanoplates having a heterojunction-like structure (CoP@a-CoOx plates).

[0537] K10. The fuel cell of K4, wherein the first electrode is coated with a first composite catalyst material on a side between the first plate and the first electrode and coated with a second composite catalyst material on a side between the first electrode and the polymer electrode.

[0538] K11. The first composite catalyst material comprises: a partially carbonized conductive polymer selected from polypyrrole, polyaniline, or a mixture thereof; a catalyst comprising a metal or metal oxide, comprising CoP nanoparticles embedded in amorphous cobalt oxide (CoOx) nanoplates (CoP@a-CoOx plates) having a heterojunction-like structure; The second composite catalyst material comprises: a partially carbonized conductive polymer selected from polypyrrole, polyaniline, or a mixture thereof; The fuel cell according to K10, comprising a catalyst comprising a metal or metal oxide comprising metallic cobalt.

[0539] K12. Further comprising one or more gas diffusion layers each configured to facilitate one or more of the following: Diffusion of fuel into and / or out of the channels of the second plate; Diffusion of oxygen, such as from air, into and / or out of the channels of the first plate; Diffusion of fuel or its derivatives into and / or out of the membrane; and The fuel cell according to any one of paragraphs K2-K11, further comprising diffusion of a fuel or a derivative thereof into and / or out of the membrane.

[0540] K13. The fuel cell according to item K12, wherein the gas diffusion layer has a hydrophobic coating.

[0541] K14. The fuel cell according to any one of items K2 to K13, wherein the first electrode comprises carbon cloth.

[0542] K15. The fuel cell according to any one of paragraphs K2-K13, wherein the first electrode comprises carbon paper.

[0543] K16. The fuel cell according to any one of items K2-K13, wherein the first electrode comprises a metal frit.

[0544] K17. The fuel cell according to item K12, wherein the gas diffusion layer comprises a porous structure of fibers or open cell foam.

[0545] K18. The fuel cell according to any one of the items K2 to K17, wherein the first plate and the second plate are configured to at least partially contain the fuel, oxygen and reaction products in the fuel cell, but not to contain one or more of the following: including a rigid element for structurally supporting the first electrode, the membrane, and the second electrode; comprising first and second electrodes and a conductive element for electrically connecting the electrodes in a circuit for transporting electrons between the electrodes; The device includes a structure in which a first flow path and a second flow path are formed.

[0546] K19. A fuel cell stack comprising a plurality of fuel cells arranged in series, the plurality of fuel cells comprising at least one fuel cell according to any one of items K1 to K18.

[0547] K20. The fuel cell stack according to item K19, wherein the fuel cell stack does not include a cooling element.

[0548] K21. The fuel cell according to item K2, wherein the catalyst on the one or more first catalyst layers catalyzes the OER and / or ORR reactions.

[0549] K22. The fuel cell of any one of items K1-K21, wherein the second plate includes a flow path formed on a surface facing the second electrode and configured to provide fluid to and receive fluid from the second electrode.

[0550] K23. The fuel cell according to any one of items K1 to K22, wherein the fuel cell comprises a gas diffusion layer between the polymer electrolyte membrane (101) and the second electrode (103).

[0551] K24. The fuel cell according to item K23, wherein the gas diffusion layer has a hydrophobic coating.

[0552] K25. The fuel cell according to item K23 or item K24, wherein the gas diffusion layer comprises a porous structure of fibers or open cell foam.

[0553] K26. The fuel cell according to any one of items K1-K25, wherein the fuel cell is configured to receive hydrogen as the fuel via the flow channels of the second plate.

[0554] K27. The fuel cell according to any one of items K1 to K26, wherein the fuel cell comprises a hydrogen fuel cell, the fuel comprises hydrogen, the oxidant comprises air, and the reaction product comprises water.

[0555] K28. The fuel cell according to any one of items K1 to K27, wherein the first electrode comprises a fibrous layer of conductive fibers.

[0556] K29. The fuel cell according to item K28, wherein the fibers of the fiber layer comprise a metal.

[0557] K30. The fuel cell according to item K29, wherein the fiber layer comprises a non-platinum group metal.

[0558] K31. The fuel cell of item K30, wherein the fiber layer comprises a nonwoven fabric.

[0559] K32. The fuel cell according to any one of the items K1 to K31, wherein the first plate and the second plate are configured to at least partially contain the fuel, oxygen and reaction products in the fuel cell, but not to contain one or more of the following: including a rigid element for structurally supporting the first electrode, the membrane, and the second electrode; comprising first and second electrodes and a conductive element for electrically connecting the electrodes in a circuit for transporting electrons between the electrodes; The device includes a structure in which a first flow path and a second flow path are formed.

[0560] K33. The fuel cell according to any one of items K1-K32, wherein the pre-fuel cell comprises a peripheral gasket sandwiched between a first plate and a second plate and configured to include at least a polymer electrolyte membrane, a first electrode, a second electrode, one or more first catalyst layers and one or more second catalyst layers.

[0561] K34. The catalyst is cobalt, The conductive material is PANI:PPY-TsOH, The conductive polymer is partially carbonized, and The fuel cell according to any one of items K1 to K33, wherein the carbon nanofoam material is N-doped carbon nanofoam.

[0562] K35. A fuel cell stack comprising a plurality of fuel cells arranged in series, said plurality of fuel cells comprising at least one fuel cell according to any one of items K1 to K33.

[0563] Example 1 - Preparation of N-doped carbon nanofoam 171 g of sugar was dissolved in 100 ml of deionized (DI) water. The mixture was heated and stirred to dissolve the sugar until completely dissolved. The final temperature at which the sugar was completely dissolved was approximately 60°C to 80°C.

[0564] The mixture was allowed to cool to about 45° C. and 3 mg of naphthalene was added. The mixture was stirred to dissolve the naphthalene.

[0565] The resulting mixture was added to a Teflon-lined hydrothermal reactor, which was sealed and placed in a 155° C. oven for 5 hours.

[0566] The resulting mixture was allowed to cool, then the carbonaceous material was removed and washed thoroughly using successively the following steps: physical dissolution of the material, decantation, and DI filtration of the material. The filtrate was dried under vacuum in an oven at 50°C for 6-12 hours.

[0567] The material was then ground in a ball mill using 5mm-10mm steel bearings (other bearings such as alumina and zirconium could also be used) for at least 24 hours and sieved through a 43-63 micron polyamide filter.

[0568] The resulting material was nitrogen doped by treatment with 6 M HNO3 at 100 °C for 8 h, then neutralized using a mild sodium bicarbonate solution and rinsed with deionized water until a pH of 6.5–7 was reached. The material was then dried under vacuum at 50 °C for 6–12 h.

[0569] SEM micrographs of the resulting material are shown in Figures 2a and 2b. This material is a superstructure of small particulate material, approximately 1-2 μm in diameter, which coalesce to form the foamed porous material.

[0570] Example 2 - Preparation of PPy:PANI:TsOH:N-doped C composite 0.6 g of carbon nanofoam powder from Example 1 was ultrasonically dispersed in 100 ml of isopropyl alcohol for 30 minutes. 3 mmol of pyrrole and 100 ml of deionized water were added to the solution and stirred on a hot plate stirrer for another 30 minutes (without sonication). 100 ml of ammonium peroxydisulfate solution (concentration 0.06 M), 0.1902 g of toluenesulfonic acid, and 10 wt. % of PANI (emeraldine crystal form) were added and then stirred at room temperature for 4 hours.

[0571] The mixture was filtered through a Millipore PTFE and silica fritted Buchner funnel and washed three times with alternating deionized water and ethanol (76%). The wet filtrate was then dried under vacuum at 45° C. for 12 h to give the PANI-PpyTsOH / C nf -N x obtained.

[0572] Example 3 - Formation of ORR catalytic composite material 0.5 g of PANI-PpyTsOH / C from Example 2 nf -N x The framework and 10.55 wt % cobalt acetate were mixed with 200 ml of deionized water, sonicated for 1 h, then stirred vigorously for 2 h, and the solvent was then evaporated under reduced pressure.

[0573] The resulting powder was then heat-treated at 800°C for 2 hours under an argon atmosphere to produce Co-PANI-PpyTsOH / C nf -N x obtained.

[0574] Example 4 - Formation of CoP@a-CoOx catalytic material 0.5 g of cobalt acetate was added to 36 ml of ethylene glycol and sonicated for 30 minutes. The solution was heated to 200° C. for 5 hours with continuous stirring.

[0575] The solution was allowed to cool to room temperature (naturally) and the pink precipitate was collected by filtration through a Millipore Buchner funnel. The material was subsequently washed three times with deionized water and ethanol, then dried at 60 °C overnight (approximately 12 h).

[0576] The resulting filtrate was then introduced into the tube furnace under argon atmosphere with NaH2PO2 at the upstream position of the tube furnace in a mass ratio of 10:1 (NaH2PO2:filtrate). It was flushed with argon before heating for 30 min and then heated at 300 °C at a heating rate of 1 °C / min (until 300 °C was reached). Heating at 300 °C was maintained for 1 h.

[0577] The resulting product is a CoP@a-CoOx heterojunction bifunctional catalytic material.

[0578] The intermediate filtrate and CoP@a-CoOx plates can be analyzed using powder XRD measurements on a Rigaku Smartlab diffractometer using Cu-Kα radiation (λ=1.5418Å) filtered in the 2θ range of 10°-90°. The morphology of the samples can be observed by a HITACHI-S4800 field emission SEM and a FEI Tecnai G2T20 transmission electron microscope. STEM-EDX line scan and elemental mapping can be performed on a FEI Tecnai G2 F30 STWIN field emission transmission electron microscope equipped with an EDX analyzer at 200kV. XPS measurements can be performed on a PHI5000 VersaProbe spectrometer equipped with an Al-Kα X-ray source, and the data can be fitted by the software package XPSPEAK. The specific surface area and pore size distribution can be determined from the N2 adsorption-desorption isotherms using the BET and Barrett-Joyner-Halenda methods.

[0579] Example 5 - Formation of OER composite catalyst material Both CoP@a-CoOx (10.55 wt%) from Example 5 and the polymer composite (0.5 g) from Example 2 were mixed with 200 ml of deionized water with pH 6.8–7, sonicated for 1 h, and then vigorously stirred for 2 h. The solvent was then evaporated under reduced pressure, and the resulting powder was dried under vacuum at 45 °C for 12 h to obtain the desired composite catalyst material.

[0580] Example 6 - Preparation of a test fuel cell A test fuel cell was constructed using MEAs in the following order: Titanium felt cathode / conductive GDL Nafion® 212PEM Carbonaceous paper anode / conductive GDL

[0581] These were sandwiched between suitable front and back plates to form a working fuel cell.

[0582] Various catalytic composites were used in the test cells and were typically applied to the cathode / anode as follows:

[0583] General method for forming a cathode The catalyst ink was prepared by dispersing 10 mg of catalyst powder in a mixture of Millipore water (36.5 μL, 18.2 MΩcm) and ethanol (300 μL) and adding 1 wt% Nafion solution (108.5 μL, Sigma-Aldrich) as a binder phase, and sonicating the resulting mixture for 60 min.

[0584] A titanium frit with a pore diameter of 63 µm is washed with EtOH and sonicated in a 60% EtOH solution for 1 h, followed by rinsing with acetone to remove all oils and surface contaminants. An 8.8 µL aliquot of the catalyst ink is then applied to the titanium frit (0.247 cm). 2 , Pine instrument) and 800 μg cm -2 This resulted in a load of

[0585] This time, the same procedure is used to add the ORR catalyst to the other side of the titanium frit, except for the catalyst ink used.

[0586] After deposition and removal of the solvent, the electrodes are exposed to moisture, which hydrates them to an average moisture level of 5000 ppm water content, which must then be removed to less than 500 ppm for the material to function properly when incorporated into a battery cell.

[0587] To reach the target moisture level, a dehumidified dry air stream at 150°C is used with a residence time of 2 minutes. The heating mechanism is infrared radiant heating.

[0588] General method for forming anode The catalyst ink was prepared by dispersing 10 mg of catalyst powder in a mixture of Millipore water (36.5 μL, 18.2 MΩcm) and ethanol (300 μL) and adding 1 wt% Nafion solution (108.5 μL, Sigma-Aldrich) as a binder phase, and sonicating the resulting mixture for 60 min.

[0589] An 8.8 μL aliquot of the catalyst ink was then drop-cast onto a carbon paper or felt electrode (0.247 cm2, Pine instrument) and deposited at 800 μg cm -2 After deposition and removal of the solvent, the electrodes are exposed to moisture, which hydrates them to an average moisture level of 5,000 parts per million (ppm). The moisture then needs to be removed to less than 500 ppm for the material to be incorporated into a battery cell and function properly.

[0590] To reach the target moisture level, a dehumidified dry air stream at 150°C is used with a residence time of 2 minutes. The heating mechanism is infrared radiant heating.

[0591] Test Results Using this basic test cell, various catalysts were analyzed for their usefulness in fuel cells, and the results for selected catalysts are shown in Table 1 below. [Table 1]

[0592] The data shows that the Cobalt:PANI:PPY-TsOH:N doped carbon according to Example 4 provided excellent results.

[0593] This system was further investigated to determine the suitability of other cobalt salt and conductive polymer combinations.

[0594] Figure 3 shows the RDE polarization curves for various cobalt salts (cobalt acetate, cobalt chloride, cobalt nitrate, and cobalt oxide). Cobalt acetate and cobalt nitrate provide the highest currents at low potentials, with cobalt acetate giving the best results overall.

[0595] Figure 4 shows plots of current density vs. power density and current density vs. cell voltage for polypyrrole-based systems with and without toluenesulfonic acid as the polymerization acid, showing that doping with toluenesulfonic acid results in more favorable power density and cell voltage across all current densities.

[0596] 5a-5f show the current density versus potential for the Co:PANI:Ppy-TsOH:N doped carbon composites formed according to Example 4 at different heating temperatures. The plots show that the best performance is achieved when the samples are heated at 800 °C according to Example 3.

[0597] Example 7 A variety of catalysts from groups 5 to 11 of the periodic table were tested and their performance was tested in a fuel cell environment.

[0598] Basic protocol for catalyst synthesis The basic protocol for the synthesis of the catalytic materials was via the polyol method, which is well known in the art and involves suspending the metal precursors in a polyol such as ethylene glycol and heating the suspension. The steps necessary to induce crystallization of each catalytic species were then carried out.

[0599] The following materials were obtained in the following manner:

[0600] Industrial grade MoS2 was purchased from Sigma Aldrich and was distributed into nanoplatelets using ultrasonication in an industry standard process.

[0601] IrOx was purchased from Sigma Aldrich.

[0602] V2O5 was purchased directly from Chemcor.

[0603] Test Data The data given in Table 2 was collected using rotating disk electrode and sweep probe voltammetry to test and measure mock-up fuel cell membrane electrode assemblies (MEAs) using a standard Pt / C reference electrode. [Table 2]

Claims

1. 1. A fuel cell comprising one or more first catalyst layers, the one or more first catalyst layers comprising: a catalyst comprising a metal or metal oxide of Groups 4 to 11; a conductive material comprising a conductive polymer; and a composite catalyst material comprising: A fuel cell, wherein the catalyst and the conductive material are supported by an (N-doped) carbon nanofoam material.

2. a polymer electrolyte membrane (101) having a first electrode (102) on one side and a second electrode (103) on the opposite side, the polymer electrolyte membrane (101), the first electrode (102), and the second electrode (103) being disposed between a first plate (104) and a second plate (105); the first plate (104) is disposed adjacent to the first electrode (102), the second plate (105) is disposed adjacent to the second electrode (105), the first plate optionally including a polymer electrolyte membrane (101) formed on a surface thereof facing the first electrode (102) and configured to supply a fluid to the first electrode (102) and receive a fluid from the first electrode (102); the one or more first catalyst layers located between the first plate (104) and the second plate (105), The one or more first catalyst layers a catalyst comprising a metal or metal oxide of Groups 4 to 11; a conductive material comprising a conductive polymer; and a composite catalyst material comprising:

10. The fuel cell (100) of claim 1, wherein the catalyst and the conductive material comprise the one or more first catalyst layers supported by an (N-doped) carbon nanofoam material.

3. 3. The fuel cell of claim 1, wherein the composite catalyst material coats the first electrode (102).

4. 4. The fuel cell of claim 3, wherein the composite catalyst material has a superstructure of coalesced particles, the diameter of the particles being 0.01 to 2 μm.

5. 3. The fuel cell of claim 1, wherein the superstructure has a tortuous path of open pores at least three times the average diameter of the individual particles.

6. The composite catalyst material comprises: a catalyst comprising a metal or metal oxide of Groups 4 to 11; a conductive material comprising a partially carbonized conductive polymer; the catalyst and the conductive material are supported by an (N-doped) carbon nanofoam material; 3. The fuel cell of claim 1 or 2, wherein the (N-doped) carbon nanofoam material is encased in the conductive material.

7. 3. The fuel cell of claim 1, wherein the conductive material comprises a core comprising a conductive polymer and a shell comprising a conductive carbonized material.

8. 3. The fuel cell according to claim 1, wherein the conductive polymer is a poly-N-aryl polymer.

9. 9. The fuel cell of claim 8, wherein the conductive polymer is selected from polypyrrole, polyaniline, or a mixture thereof.

10. 3. The fuel cell according to claim 1, wherein the metal or metal oxide in the composite catalyst material comprises a cobalt-based catalyst.

11. 11. The fuel cell of claim 10, wherein the metal or metal oxide in the composite catalyst material comprises metallic cobalt.

12. 11. The fuel cell of claim 10, wherein the metal or metal oxide in the composite catalyst material on the first electrode (102) comprises CoP nanoparticles embedded in amorphous cobalt oxide (CoOx) nanoplates (CoP@a-CoOx plates) having a heterojunction-like structure.

13. 3. The fuel cell of claim 2, wherein the first electrode (102) is coated with a first composite catalyst material on a side between the first plate (104) and the first electrode (102) and with a second composite catalyst material on a side between the first electrode and the polymer electrode membrane.

14. The first composite catalyst material comprises: a partially carbonized conductive polymer selected from polypyrrole, polyaniline, or a mixture thereof; a catalyst comprising a metal or metal oxide including amorphous cobalt oxide (CoP) nanoparticles embedded in amorphous CoOx nanoplates (CoP@a-CoOx plates) having a heterojunction-like structure; The second composite catalyst material comprises: a partially carbonized conductive polymer selected from polypyrrole, polyaniline, or a mixture thereof; 14. The fuel cell of claim 13, comprising a catalyst comprising a metal or metal oxide comprising metallic cobalt.

15. 3. The fuel cell of claim 1 or 2, wherein the (N-doped) carbon nanofoam material is an N-doped carbon nanofoam material.

16. 1. A fuel cell comprising one or more first catalyst layers, the one or more first catalyst layers comprising: a catalyst comprising cobalt; a conductive material comprising a conductive polymer, the conductive polymer being PANI:PPY-TsOH, the conductive polymer being partially carbonized; and a composite catalyst material comprising: The fuel cell, wherein the catalyst and the conductive material are supported by an N-doped carbon nanofoam material.

17. 19. A fuel cell stack comprising a plurality of fuel cells arranged in series, said plurality of fuel cells including at least one fuel cell according to claim 1, 2 or 16.

18. a catalyst comprising a metal or metal oxide of Groups 4 to 11; a conductive material comprising a conductive polymer; A composite catalyst material, wherein the catalyst and the conductive material are supported by an (N-doped) carbon nanofoam material.

19. 19. The composite catalytic material of claim 18, wherein said Group 4 to Group 11 metals or metal oxides are selected from the metals Co, Fe, Ni, alloys of Co, Fe, Ni, oxides of Co, Fe, Ni, or mixtures thereof, preferably where Fe is present, Fe is in the 3+ oxidation state.

20. 20. The composite catalytic material of claim 19, wherein the composite catalytic material comprises a cobalt-based catalyst.

21. 21. The composite catalytic material of claim 20, wherein said cobalt-based catalyst is metallic cobalt.

22. The composite catalyst material according to any one of claims 18 to 21, wherein said conductive polymer is a poly-N-aryl polymer.

23. The composite catalyst material according to any one of claims 18 to 21, wherein the conductive polymer is partially carbonized.

24. 22. The composite catalyst material according to any one of claims 18 to 21, wherein the conductive material comprises a core comprising a conductive polymer and a shell comprising a conductive carbonized material.

25. 22. The composite catalyst material according to any one of claims 18 to 21, wherein the composite catalyst material has a superstructure of coalesced particles, and the diameter of the particles is 0.01 to 2 μm.

26. 26. The composite catalyst material of claim 25, wherein said superstructure has a tortuous path of open pores at least three times the average diameter of said individual particles.

27. 27. The composite catalyst material of claim 26, wherein said superstructure has a tortuous path of open pores 5 to 50 times the average diameter of said individual particles.

28. 22. The composite catalytic material according to any one of claims 18 to 21, wherein the material comprises 1 to 20 wt% catalytic metal.

29. 22. The composite catalyst material according to any one of claims 18 to 21, wherein the (N-doped) carbon nanofoam material is enveloped by the conductive material.

30. Use of the composite catalytic material according to any one of claims 18 to 21 for promoting a four-electron redox reaction.

31. Use of the composite catalytic material according to any one of claims 18 to 21 for promoting a direct (one-step) redox reaction converting oxygen to water.

32. A method for forming the composite catalyst material of any one of claims 18 to 21, comprising the steps of: (i) forming a conductive polymer by oxidative polymerization in the presence of an (N-doped) carbon nanofoam material to form a polymer:N-doped carbon nanofoam composite; (ii) depositing a catalytic metal on said (N-doped) carbon nanofoam material; (iii) optionally, partially carbonizing said conductive polymer.

33. 33. The method of claim 32, wherein step (ii) comprises co-dispersing the materials and removing the solvent.

34. 34. The method of claim 33, wherein after removal of the solvent, the resulting material can optionally be partially carbonized by heating in an inert atmosphere to a temperature sufficient to decompose the conductive polymer.

35. 35. The method of claim 34, wherein the resulting material is heated at a temperature between 500°C and 1100°C.

36. 36. The method of claim 35, wherein the resulting material is heated for 30 minutes to 4 hours.

37. 33. The method of claim 32, wherein the polymerization in step (i) occurs prior to combining with the catalytic metal.

38. 33. The method of claim 32, wherein the forming of the conductive polymer in step (i) is carried out in the presence of a non-polymeric acid.

39. A method comprising applying the composite catalyst material of any one of claims 18 to 21 to an electrode.

40. 40. The method of claim 39, wherein the composite catalytic material is applied to a surface of the electrode prior to carbonization, and the partial carbonization step is performed in situ on the electrode.

41. 41. The method of claim 40, wherein the composite catalyst material can be applied to the electrode as a dispersion including a binder.

42. 42. The method of claim 41, wherein the binder is a fluorinated acid polymer.

43. 43. The method of claim 42, wherein the binder is used at less than 5% by weight.

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