Reactor with advanced architecture for electrochemical reactions of carbon dioxide, carbon monoxide and other chemical compounds

Abstract

This application relates to reactors with advanced architecture for electrochemical reactions of carbon dioxide, carbon monoxide and other chemical compounds. A platform technology has been developed that enables the electrochemical conversion of CO x A novel membrane electrode assembly is used in the reduction reactor, which includes a cathode layer, an anode layer, a membrane layer disposed between the cathode and anode layers, the membrane electrically connecting the cathode and anode layers. The reactor can be used to synthesize a wide range of carbon-based compounds from carbon dioxide and other carbon-containing gases.

Description

[0001] This application is a divisional application of the application filed on May 3, 2017, with application number 201780035746.8 and invention title "Reactor with Advanced Architecture for Electrochemical Reactions of CO2, CO and Other Chemical Compounds".

[0002] Cross-references to related applications

[0003] This application claims the benefit of U.S. Provisional Application No. 62 / 331,387, filed May 3, 2016, which is incorporated herein by reference in its entirety. Technical Field

[0004] This disclosure generally pertains to the field of electrochemical reactions, and more specifically, to methods for converting CO... x Apparatus and methods for the electrochemical reduction of (CO2, CO, or a combination thereof) into carbon-containing chemical compounds. background

[0005] Anthropogenic CO2 emissions are already linked to climate change.

[0006] In response to growing concerns about global greenhouse gas emissions, technologies that can recycle CO2 into high-value products have received increasing attention.

[0007] CO x The electrochemical reduction of (CO2, CO, or a combination thereof) involves only three inputs: CO x The source of protons and electricity is used to convert them into fuels, chemicals, and other products such as methanol, ethanol, carbon monoxide, and acetic acid. However, industrial-scale production of such fuels and chemicals has been impossible. One obstacle is the lack of suitable electrochemical reactors. A difficulty in achieving efficient reactors using conventional designs is due to CO2... x The low solubility of CO in aqueous solution leads to its concentration in the reactor. x Poor transport to the catalyst surface and uncontrollable competitive water reduction reaction leading to hydrogen production.

[0008] Overview

[0009] This disclosure describes new and useful methods for reducing CO2. x An electrochemical reactor that overcomes the aforementioned shortcomings of conventional reactors. It reacts with CO2 dissolved in water. x Conversely, gaseous CO x It can be supplied to the reactor to achieve efficient transport and product productivity. (Regarding CO) xThe ion-conductive polymer of the conversion catalyst minimizes competitive hydrogen formation reactions. The reactor features high energy efficiency, high current density, fast response time, and robustness, while also offering flexibility in the variety of chemical products it can produce.

[0010] In one embodiment of the invention, a method for CO is provided. x A membrane electrode assembly (MEA) is used in a reduction reactor. The MEA has a cathode layer comprising a reduction catalyst and a first ion-conducting polymer, and an anode layer comprising an oxidation catalyst and a second ion-conducting polymer. A polymer electrolyte membrane comprising a third ion-conducting polymer exists between the anode and cathode layers. The polymer electrolyte membrane provides ion communication between the anode and cathode layers. A cathode buffer layer, comprising a fourth ion-conducting polymer, is also present between the cathode layer and the polymer electrolyte membrane. Three types of ion-conducting polymers are present: anion conductors, cation conductors, and cation and anion conductors. At least two of the first, second, third, and fourth ion-conducting polymers are from different categories of ion-conducting polymers.

[0011] In one arrangement, the reduction catalyst is selected from the group consisting of: V, Cr, Mn, Fe, Co, Ni, Cu, Sn, Zr, Nb, Mo, Au, Ru, Rh, Pd, Ag, Cd, Hf, Ta, W, Re, Ir, Pt, Hg, Al, Si, In, Ga, Tl, Pb, Bi, Sb, Te, Sm, Tb, Ce, and Nd, combinations thereof, and / or any other suitable reduction catalyst. The reduction catalyst may also include conductive support particles selected from the group consisting of: carbon, boron-doped diamond, fluorine-doped tin oxide, combinations thereof, and / or any other suitable reduction catalyst.

[0012] In one arrangement, the cathode layer comprises between 10 wt% and 90 wt% of a first ion-conducting polymer. The first ion-conducting polymer may include at least one ion-conducting polymer that is an anion conductor.

[0013] The first ion-conducting polymer may contain one or more covalently bonded, positively charged functional groups configured to transport mobile, negatively charged ions. The first ion-conducting polymer may be selected from the group consisting of: amination-modified tetramethylpolyphenylene; quaternary ammonium polymers based on poly(ethylene-co-tetrafluoroethylene); quaternized polysulfones, blends thereof, and / or any other suitable ion-conducting polymer. The first ion-conducting polymer may be configured to solubilize bicarbonate or hydroxide.

[0014] The first ion-conducting polymer may include at least one ion-conducting polymer that is a cationic and anionic conductor. The first ion-conducting polymer may be selected from the group consisting of polyethers capable of transporting cationic and anionic ions and polyesters capable of transporting cationic and anionic ions. The first ion-conducting polymer may be selected from the group consisting of polyethylene oxide, polyethylene glycol, polyvinylidene fluoride, and polyurethane.

[0015] In one arrangement, the oxidation catalyst is selected from the group consisting of: Ir, Pt, Ni, Ru, Pd, Au, and alloys thereof, IrRu, PtIr, Ni, NiFe, stainless steel, and combinations thereof, and / or any other suitable metal or metal oxide. The oxidation catalyst may also comprise conductive support particles selected from the group consisting of carbon, boron-doped diamond, and titanium.

[0016] In one arrangement, the anode layer comprises between 5 wt% and 95 wt% of a second ion-conducting polymer. The second ion-conducting polymer may include at least one ion-conducting polymer that is a cation conductor.

[0017] The second ion-conducting polymer may include one or more polymers comprising covalently bonded, negatively charged functional groups configured to transport mobile, positively charged ions. The second ion-conducting polymer may be selected from the group consisting of: ethanesulfonyl fluoride, 2-[1-[difluoro-[(trifluorovinyl)oxy]methyl]-1,2,2,2-tetrafluoroethoxy]-1,1,2,2-tetrafluoro-, with tetrafluoroethylene, tetrafluoroethylene-perfluoro-3,6-dioxa-4-methyl-7-octenesulfonic acid copolymers, other perfluorosulfonic acid polymers, blends thereof, and / or any other suitable ion-conducting polymer.

[0018] In one arrangement, the third ion-conducting polymer comprises at least one ion-conducting polymer that is a cationic conductor. The third ion-conducting polymer may contain one or more covalently bonded, negatively charged functional groups configured to transport mobile, positively charged ions. The third ion-conducting polymer may be selected from the group consisting of: ethanesulfonyl fluoride, 2-[1-[difluoro-[(trifluorovinyl)oxy]methyl]-1,2,2,2-tetrafluoroethoxy]-1,1,2,2-tetrafluoro-, with tetrafluoroethylene, tetrafluoroethylene-perfluoro-3,6-dioxa-4-methyl-7-octenesulfonic acid copolymers, other perfluorosulfonic acid polymers, blends thereof, and / or any other suitable ion-conducting polymer.

[0019] In one arrangement, the cathode buffer layer has a porosity between 0.01% and 95% (e.g., by weight, by volume, by mass, etc., approximately between...). However, in other arrangements, the cathode buffer layer may have any suitable porosity (e.g., between 0.01%-95%, 0.1%-95%, 0.01%-75%, 1%-95%, 1%-90%, etc.).

[0020] In one arrangement, the fourth ion-conducting polymer comprises at least one ion-conducting polymer that is an anionic conductor. The fourth ion-conducting polymer may contain one or more covalently bonded, positively charged functional groups configured to transport mobile, negatively charged ions. The fourth ion-conducting polymer may be selected from the group consisting of: amination-modified tetramethylpolyphenylene; quaternary ammonium polymers based on poly(ethylene-co-tetrafluoroethylene); quaternized polysulfones; blends thereof; and / or any other suitable ion-conducting polymer.

[0021] In one arrangement, the first ion-conducting polymer and the fourth ion-conducting polymer are from the same category. In another arrangement, the second ion-conducting polymer and the third ion-conducting polymer are from the same category.

[0022] In one arrangement, the membrane electrode assembly further includes an anode buffer layer between the anode layer and the polymer electrolyte membrane, the anode buffer layer comprising a fifth ion-conducting polymer.

[0023] In another arrangement, the fifth ion-conducting polymer of the membrane electrode assembly comprises at least one ion-conducting polymer that is a cation conductor. The fifth ion-conducting polymer may contain one or more covalently bonded, negatively charged functional groups configured to transport mobile, positively charged ions.

[0024] The fifth ion-conducting polymer may be selected from the group consisting of: ethanesulfonyl fluoride, 2-[1-[difluoro-[(trifluorovinyl)oxy]methyl]-1,2,2,2-tetrafluoroethoxy]-1,1,2,2-tetrafluoro-, with tetrafluoroethylene, tetrafluoroethylene-perfluoro-3,6-dioxa-4-methyl-7-octenesulfonic acid copolymers, other perfluorosulfonic acid polymers, blends thereof, and / or any other suitable ion-conducting polymer. The second and fifth ion-conducting polymers may be from the same category.

[0025] In one arrangement, the anode buffer layer has a porosity between 0.01% and 95% (e.g., by weight, by volume, by mass, etc., approximately between...). However, in other arrangements, the anode buffer layer may have any suitable porosity (e.g., between 0.01%-95%, 0.1%-95%, 0.01%-75%, 1%-95%, 1%-90%, etc.).

[0026] In another embodiment of the invention, a method for CO is provided. x A membrane electrode assembly (MEA) is used in a reduction reactor. The MEA has a cathode layer comprising a reduction catalyst and a first ion-conducting polymer, and an anode layer comprising an oxidation catalyst and a second ion-conducting polymer. A polymer electrolyte membrane exists between the anode and cathode layers. The polymer electrolyte membrane contains a third ion-conducting polymer and provides ion communication between the anode and cathode layers. Three types of ion-conducting polymers are present: anion conductors, cation conductors, and cation and anion conductors. At least two of the first, second, and third ion-conducting polymers are from different categories of ion-conducting polymers.

[0027] In another embodiment of the invention, CO is provided. x A reduction reactor. The reactor has at least one electrochemical cell, which includes any membrane electrode assembly described herein. The reactor also has a cathode support structure adjacent to the cathode, which includes a cathode polar plate, at least one cathode gas diffusion layer, at least one inlet, and at least one outlet. An anode support structure adjacent to the anode is also present. The anode support structure includes an anode polar plate and at least one anode gas diffusion layer, at least one inlet, and at least one outlet.

[0028] In yet another embodiment of the invention, operation of CO is provided. xA method for a reduction reactor. This method results in the production of reaction products. The process may include: providing an electrochemical reactor comprising at least one electrochemical cell, a cathode support structure adjacent to the cathode, and an anode cell support structure adjacent to the anode, the electrochemical cell comprising a membrane electrode assembly, the cathode support structure comprising a cathode plate, at least one cathode gas diffusion layer, at least one gas inlet, and at least one gas outlet, the anode cell support structure comprising an anode plate and at least one anode gas diffusion layer, at least one inlet, and at least one outlet; applying a DC voltage to the cathode plate and the anode plate; supplying one or more oxidizing reactants to the anode and allowing an oxidation reaction to occur; supplying one or more reducing reactants to the cathode and allowing a reduction reaction to occur; collecting oxidation reaction products from the anode; and collecting reduction reaction products from the cathode.

[0029] The oxidizing agent can be selected from the group consisting of: hydrogen, methane, ammonia, water, or combinations thereof, and / or any other suitable oxidizing agent. In one arrangement, the oxidizing agent is water.

[0030] The reducing reactant can be selected from the group consisting of: carbon dioxide, carbon monoxide, combinations thereof, and / or any other suitable reducing reactant. In one arrangement, the reducing reactant is carbon dioxide.

[0031] This application provides the following:

[0032] 1) A membrane electrode assembly, the membrane electrode assembly comprising:

[0033] ● Cathode layer, the cathode layer comprising a reduction catalyst and a first anion-conducting polymer;

[0034] ● An anode layer comprising an oxidation catalyst and a first cationic conductive polymer;

[0035] ● A membrane layer comprising a second cationic conductive polymer is disposed between the cathode layer and the anode layer, the membrane layer electrically connecting the cathode layer and the anode layer; and

[0036] ● A cathode buffer layer having a first porosity between about 0.01% and 95% by volume, the cathode buffer layer comprising a second anionic conductive polymer, wherein the cathode buffer layer is disposed between the cathode layer and the film layer and electrically connects the cathode layer and the film layer.

[0037] 2) The membrane electrode assembly as described in 1) further includes an anode buffer layer comprising a third cationic conductive polymer, the anode buffer layer being disposed between the membrane layer and the anode layer.

[0038] 3) The membrane electrode assembly as described in 2), wherein the second and third cationic conductive polymers comprise perfluorosulfonic acid (PFSA) polymers, and wherein the anode buffer layer has a second porosity between about 0.01% and 95% by volume.

[0039] 4) The membrane electrode assembly as described in 2), wherein the cathode buffer layer further comprises inert filler particles, wherein the first porosity is formed by the inert filler particles.

[0040] 5) The membrane electrode assembly as described in 4), wherein the inert filler particles include at least one of diamond particles, boron-doped diamond particles, polyvinylidene fluoride (PVDF) particles, and polytetrafluoroethylene (PTFE) particles.

[0041] 6) The membrane electrode assembly as described in 4), wherein the size of each of the inert filler particles is between about 10 nanometers and about 200 nanometers.

[0042] 7) The membrane electrode assembly as described in 2), wherein the second anion-conducting polymer is selected from the group consisting of Sustainion, FumaSep FAA-3, and Tokuyama anion exchange polymer.

[0043] 8) The membrane electrode assembly as described in 1), wherein the first anionic conductive polymer and the second anionic conductive polymer comprise Sustainion.

[0044] 9) A membrane electrode assembly, the membrane electrode assembly comprising:

[0045] ● Cathode layer, the cathode layer comprising a reduction catalyst and a first anion-conducting polymer;

[0046] ● An anode layer comprising an oxidation catalyst and a first cationic conductive polymer;

[0047] ● A membrane layer comprising a second anionic conductive polymer is disposed between the cathode layer and the anode layer, the membrane layer electrically connecting the cathode layer and the anode layer; and

[0048] ●An anode buffer layer comprising a second cationic conductive polymer, wherein the anode buffer layer is disposed between the anode layer and the film layer and conductively connects the anode layer and the film layer.

[0049] 10) The membrane electrode assembly as described in 9), wherein the membrane layer has a first porosity between about 0.01% and 95% by volume.

[0050] 11) The membrane electrode assembly as described in 10), wherein the second anion-conducting polymer is selected from the group consisting of Sustainion, FumaSep FAA-3, and Tokuyama anion exchange polymer.

[0051] 12) The membrane electrode assembly as described in 10) further includes a cathode buffer layer having a second porosity between about 0.01% and 95% by volume, the cathode buffer layer comprising a third anionic conductive polymer, wherein the cathode buffer layer is disposed between the cathode layer and the membrane layer and electrically connects the cathode layer and the membrane layer.

[0052] 13) A type of CO x Reduction reactor, the CO x The reduction reactor includes:

[0053] ● Membrane electrode assembly, the membrane electrode assembly comprising:

[0054] o Cathode layer, the cathode layer comprising a reduction catalyst and a first anion-conducting polymer;

[0055] o Anode layer, the anode layer comprising an oxidation catalyst and a first cationic conductive polymer; and

[0056] o film layer, the film layer comprising a second cationic conductive polymer, the film layer being disposed between the cathode layer and the anode layer and conductively connecting the cathode layer and the anode layer;

[0057] ● Cathode manifold, the cathode manifold being coupled to the cathode layer; and

[0058] ● An anode manifold, which is coupled to the anode layer.

[0059] 14) CO as described in 13) x A reduction reactor, wherein the cathode manifold includes a cathode support structure adjacent to the cathode layer, the cathode support structure comprising:

[0060] ● Cathode plate;

[0061] ● A cathode gas diffusion layer is disposed between the cathode plate and the cathode layer.

[0062] ● A first inlet, which is fluidly connected to the cathode gas diffusion layer; and

[0063] ● A first outlet, which is fluidly connected to the cathode gas diffusion layer; and

[0064] The anode manifold includes an anode support structure adjacent to the anode layer, the anode support structure comprising:

[0065] ● Anode plate;

[0066] ● An anode gas diffusion layer is disposed between the anode plate and the anode layer;

[0067] ● A second inlet, which is fluidly connected to the anode gas diffusion layer; and

[0068] ● The second outlet is fluidly connected to the anode gas diffusion layer.

[0069] 15) CO as described in 13) x A reduction reactor, wherein the membrane electrode assembly further includes a cathode buffer layer comprising a second anion-conducting polymer, wherein the cathode buffer layer is disposed between the cathode layer and the membrane layer and conductively connects the cathode layer and the membrane layer.

[0070] 16) CO as described in 15) x The reduction reactor, wherein the cathode buffer layer of the membrane electrode assembly has a first porosity between approximately 1% and 90% by volume.

[0071] 17) CO as described in 15) x The reduction reactor contains anionic conductive polymers selected from the group consisting of FumaSep FAA-3 and Sustainion.

[0072] 18) CO as described in 15) xA reduction reactor, wherein the second cationic conductive polymer is selected from the group consisting of: Nafion 324, Nafion 350, Nafion 417, Nafion 424, Nafion 438, Nafion 450, Nafion 521, and Nafion 551.

[0073] 19) CO as described in 15) x A reduction reactor, wherein the second cationic conductive polymer is selected from the group consisting of Aquivion, GORE-SELECT, and Flemion.

[0074] 20) CO as described in 19) x A reduction reactor, wherein the first anionic conductive polymer and the second anionic conductive polymer comprise the same polymer.

[0075] 21) CO as described in 15) x The reduction reactor, wherein the second anionic conductive polymer is selected from the group consisting of FumaSep FAA-3, Sustainion, and Tokuyama anion exchange polymers.

[0076] 22) CO as described in 13) x A reduction reactor, wherein the second cationic conductive polymer comprises PSFA. Brief description of the attached diagram

[0077] When read in conjunction with the accompanying drawings, the foregoing and other aspects will be readily understood by those skilled in the art based on the following description of the illustrative embodiments.

[0078] Figure 1 A standard membrane electrode assembly used in a conventional water electrolysis reactor is shown, which produces hydrogen and oxygen.

[0079] Figure 2 It is an embodiment of the invention for use in new CO x A schematic diagram of the membrane electrode assembly used in a reduction reactor (CRR).

[0080] Figure 3 This is a schematic diagram illustrating possible morphologies of two different types of catalysts for loading onto catalyst support particles according to embodiments of the present invention.

[0081] Figure 4 This is a schematic diagram of a membrane electrode assembly for use in a new CRR according to another embodiment of the present invention.

[0082] Figure 5 This is a schematic diagram illustrating a membrane electrode assembly for use in a new CRR according to yet another embodiment of the present invention.

[0083] Figure 6 CO is shown according to an embodiment of the present invention. x A schematic diagram of the main components of a reduction reactor (CRR).

[0084] Figure 7 This is a schematic diagram showing the main components of a CRR according to one embodiment of the present invention, wherein arrows indicate the flow of molecules, ions and electrons.

[0085] Figure 8 This is a schematic diagram showing the main inputs and outputs of a CRR reactor.

[0086] Description of the implementation plan

[0087] The preferred implementation scheme in reducing CO x (CO2, CO, or combinations thereof) are exemplified in the context of producing useful chemicals and fuels. However, those skilled in the art will readily appreciate that the materials and methods disclosed herein are desirable in their reduction reactions, and particularly in their ability to produce a variety of chemicals under various reaction conditions, which will have applications in many other contexts. For the reduction of CO x The reactor can also be used to reduce other compounds, including but not limited to: N2, SO2 x NO x Acetic acid, ethylene, O2 and any other suitable reducible compound or combination thereof.

[0088] For all purposes, all publications mentioned herein are incorporated in their entirety by reference, as if fully expounded herein.

[0089] Table 1 lists some of the abbreviations used throughout this application.

[0090] Table 1

[0091] abbreviation describe <![CDATA[CO x ]]> <![CDATA[CO2, CO or a combination thereof]]> CRR <![CDATA[CO x Reduction reactor MEA Membrane electrode assembly PEM Polymer electrolyte membrane

[0092] The term "ionically conductive polymer" is used herein to describe polymeric electrolytes having a specific conductivity greater than about 1 mS / cm for anions and / or cations. The term "anionic conductor" describes an ionically conductive polymer that primarily conducts anions (although some trace amounts of cations will still be present) and has an anionic migration number greater than about 0.85 at a thickness of about 100 micrometers. The terms "cationic conductor" and / or "cationically conductive polymer" describe an ionically conductive polymer that primarily conducts cations (e.g., a secondary amount of anionic conduction may still be present) and has a cation migration number greater than about 0.85 at a thickness of about 100 micrometers. For ionically conductive polymers described as conducting both anions and cations ("cation and anionic conductors"), neither anions nor cations have migration numbers greater than about 0.85 or less than about 0.15 at a thickness of about 100 micrometers. To say that a material conducts ions (anions and / or cations) means that the material is an ionically conductive material.

[0093] For most ion-conducting polymers, hydration is useful in enabling ion conduction. CO x Alternatively, humidification of the anode feed material can be used to deliver liquid water to the MEA to maintain the hydration of the ion-conducting polymer.

[0094] In one embodiment of the invention, a novel membrane electrode assembly for use in electrochemical cells has been developed for CO2 processing. x Reduction reactor (CRR). Table 2 lists the reactors in which CO can be converted from CO. x Some examples of useful chemicals produced.

[0095] Table 2 Exemplary CO2 and CO reduction products

[0096] Formic acid carbon monoxide methanol glyoxal methane Acetic acid Hydroxyacetaldehyde Ethylene glycol Acetaldehyde ethanol ethylene Hydroxyacetone acetone allyl alcohol propionaldehyde n-Propanol Syngas

[0097] Membrane electrode assembly

[0098] A conventional membrane electrode assembly (MEA) 100 for water electrolysis to produce hydrogen and oxygen. Figure 1 As shown in the diagram, MEA 100 has a cathode 120 and an anode 140 separated by an ion-conducting polymer layer 160, which provides a pathway for ions to travel between the cathode 120 and the anode 140. Each of the cathode 120 and anode 140 comprises an ion-conducting polymer, catalyst particles, and an electronically conductive catalyst support. The ion-conducting polymers in the cathode 120, anode 140, and ion-conducting polymer layer 160 are either all cationic conductors or all anionic conductors.

[0099] Standard MEA 100 is not suitable for use in CRR. When all ionically conductive polymers are cationic conductors, the environment favors water reduction to produce hydrogen in an undesirable side reaction. Hydrogen production reduces CO2. x The rate of product formation is reduced, thus decreasing the overall efficiency of the process. When all ionically conductive polymers are anionic conductors, CO2 reacts with hydroxide anions in the ionically conductive polymer to form bicarbonate anions. The electric field in the reactor moves the bicarbonate anions from the cathode side of the battery to the anode side. At the anode, the bicarbonate anions can decompose back into CO2 and hydroxide ions. This results in a net movement of CO2 from the cathode to the anode, where it does not react and is diluted by the anode reactants and products. This loss of CO2 to the anode side of the battery reduces the efficiency of the process.

[0100] According to an embodiment of the present invention, the novel membrane electrode assembly (MEA) 200 for use in CRR is... Figure 2 As shown in the diagram, the MEA 200 has a cathode 220 and an anode 240 separated by an ion-conducting polymer layer 260, which provides a pathway for ions to travel between the cathode 220 and the anode 240. Generally, it is particularly useful if the cathode and anode layers of the MEA are porous to facilitate gas and fluid transport and maximize the amount of catalyst surface area available for the reaction.

[0101] Cathode 220 comprises reduction catalyst particles, electronically conductive support particles providing support for the reduction catalyst particles, and a blend of cathode ion-conducting polymers. There is a trade-off in the amount of cathode ion-conducting polymer in the cathode. It is important to include sufficient cathode ion-conducting polymer to provide adequate ionic conductivity. However, it is also important that the cathode is porous, allowing reactants and products to move easily through the cathode and maximizing the amount of catalyst surface area available for the reaction. In various arrangements, the cathode ion-conducting polymer constitutes part of the material in the cathode layer at a range between 30 wt% and 70 wt%, between 20 wt% and 80 wt%, or somewhere in the range between 10 wt% and 90 wt%, or any other suitable range. The wt% of the ion-conducting polymer in the cathode is selected to result in the cathode layer porosity and ionic conductivity, which contribute to CO2. xReduction yields the highest current density. Examples of materials that can be used for the reduction catalyst particles include, but are not limited to, transition metals such as V, Cr, Mn, Fe, Co, Ni, Cu, Zr, Nb, Mo, Au, Ru, Rh, Pd, Ag, Cd, Hf, Ta, W, Re, Ir, Pt, and Hg, combinations thereof, and / or any other suitable materials. Other catalyst materials may include alkali metals, alkaline earth metals, lanthanides, actinides, and post-transition metals such as Sn, Si, Ga, Pb, Al, Tl, Sb, Te, Bi, Sm, Tb, Ce, Nd, and In, combinations thereof, and / or any other suitable catalyst materials. The catalyst may be in the form of nanoparticles ranging in size from about 1 nm to 100 nm, particles ranging in size from about 0.2 nm to 10 nm, particles ranging in size from about 1 nm to 1000 nm, or particles in any other suitable size range.

[0102] The conductive carrier particles in the cathode can be carbon particles in various forms. Other possible conductive carrier particles include boron-doped diamond or fluorine-doped tin oxide. In one arrangement, the conductive carrier particles are Vulcan carbon. The conductive carrier particles can be nanoparticles. The size of the conductive carrier particles ranges from about 20 nm to 1000 nm or any other suitable range. It is particularly useful if the conductive carrier particles are compatible with the chemicals present in the cathode 220 when CRR is operating, are reduction-stable, and have a high hydrogen-generating overpotential so that they do not participate in any electrochemical reactions.

[0103] Typically, such conductive support particles are larger than reduction catalyst particles, and each conductive support particle can support many reduction catalyst particles. Figure 3 This is a schematic diagram illustrating possible configurations of two different types of catalysts supported on catalyst carrier particles 310 (e.g., carbon particles). First-type catalyst particles 330 and second-type catalyst particles 350 are attached to the catalyst carrier particles 310. In various arrangements, only one type of catalyst particle may be present, or more than two types of catalyst particles may be attached to the catalyst carrier particles 310.

[0104] Again, refer to Figure 2The anode 240 comprises a blend of an oxidation catalyst and an ion-conducting polymer. There is a trade-off in the amount of ion-conducting polymer in the anode. It is important to include sufficient ion-conducting polymer to provide adequate ionic conductivity. However, it is also important that the anode is porous, allowing reactants and products to move easily through the anode and maximizing the amount of catalyst surface area available for the reaction. In various arrangements, the ion-conducting polymer in the anode constitutes approximately 50 wt% of the layer, or between approximately 5 wt% and 20 wt%, between 10 wt% and 90 wt%, between 20 wt% and 80 wt%, between 25 wt% and 70 wt%, or any suitable range. It is particularly useful if the anode 240 can withstand high voltages, such as above approximately 1.2 V relative to a reversible hydrogen electrode. It is also particularly useful if the anode 240 is porous to maximize the amount of catalyst surface area available for the reaction and to facilitate gas and liquid transport.

[0105] Depending on the reactants fed to the anode and the anode catalyst, there are various oxidation reactions that can occur at the anode. Table 3 lists the oxidation reactions that can occur at the anode and some exemplary catalysts supporting these reactions. Oxidation catalysts can be in the form of a structured network or in particulate form. If the oxidation catalyst is in particulate form, the particles can be loaded with electronically conductive support particles. The conductive support particles can be nanoparticles. It is particularly useful if the conductive support particles are compatible with the chemicals present in anode 240 when CRR is operating and are oxidically stable so that they do not participate in any electrochemical reactions. It is particularly useful to select the conductive support particles in consideration of the voltage and reactants at the anode. In some arrangements, the conductive support particles are titanium, which is well-suited for high voltages. In other arrangements, the conductive support particles are carbon, which can be most useful at low voltages. Typically, such conductive support particles are larger than oxidation catalyst particles, and each conductive support particle can load many oxidation catalyst particles. Examples of such arrangements are shown in... Figure 3 As shown in Table 3 and discussed above, in one arrangement, the oxidation catalyst is iridium-ruthenium oxide. Examples of other materials that can be used as oxidation catalysts include, but are not limited to, those shown in Table 3. It should be understood that many of these metal catalysts can be in the form of oxides, especially under reaction conditions.

[0106] Table 3

[0107]

[0108] The ion exchange layer 260 may include three sublayers: a cathode buffer layer 225, a polymer electrolyte membrane (PEM) 265, and an optional anode buffer layer 245. Some layers in the ion exchange layer may be porous, but it is useful if at least one layer is non-porous so that reactants and products at the cathode cannot be transported to the anode, and vice versa.

[0109] Polymer electrolyte membrane 265 exhibits high ionic conductivity (greater than approximately 1 mS / cm) and is mechanically stable. Mechanical stability can be demonstrated in various ways, such as through high tensile strength, elastic modulus, elongation at break, and tear resistance. Many commercially available membranes can be used for polymer electrolyte membrane 265. Examples include, but are not limited to, various... Formulation, GORE-SELECT (PFSA)(FuMA-Tech GmbH), and (PFSA)(Solvay).

[0110] Importantly, it should be noted that when the polymer electrolyte membrane 265 is a cation conductor and conducts protons, it contains a high proton concentration during CRR operation, while the cathode 220 operates best in the presence of a low proton concentration. Including a cathode buffer layer 225 between the polymer electrolyte membrane 265 and the cathode 220 to provide a region for the transition from a high proton concentration to a low proton concentration can be useful. In one arrangement, the cathode buffer layer 225 is an ion-conducting polymer with many of the same properties as the ion-conducting polymer in the cathode 220. The cathode buffer layer 225 provides a region for the proton concentration to transition from the high proton concentration of the polymer electrolyte membrane 265 to the low proton concentration of the cathode 220. Within the cathode buffer layer 225, protons from the polymer electrolyte membrane 265 encounter anions from the cathode 220, and they neutralize each other. The cathode buffer layer 225 helps ensure that a harmful number of protons from the polymer electrolyte membrane 265 do not reach the cathode 220 and increase the proton concentration. If the proton concentration of the cathode 220 is too high, CO2... x Reduction does not occur. High proton concentrations are considered to be in the range of about 10 molar to 0.1 molar, and low concentrations are considered to be less than about 0.01 molar.

[0111] The cathode buffer layer 225 may comprise a single polymer or multiple polymers. If the cathode buffer layer 225 comprises multiple polymers, the polymers may be mixed together or arranged in separate, adjacent layers. Examples of materials that may be used for the cathode buffer layer 225 include, but are not limited to, FumaSep FAA-3. Tokuyama anion exchange membrane material, and polyether-based polymers, such as polyethylene oxide (PEO), blends thereof, and / or any other suitable ion-conducting polymers or materials. The thickness of the cathode buffer layer is chosen to be sufficient to reduce CO concentration due to the low proton concentration. x High reduction activity. This adequacy can vary depending on the cathode buffer layer material. Typically, the thickness of the cathode buffer layer is between approximately 200 nm and 100 μm, between 300 nm and 75 μm, between 500 nm and 50 μm, or any suitable range.

[0112] It can be useful if some or all of the following layers are porous: cathode 220, cathode buffer layer 225, anode 240, and anode buffer layer 245. In some arrangements, porosity is achieved by combining inert filler particles with polymers in these layers. Suitable materials as inert filler particles include, but are not limited to, TiO2, silica, PTFE, zirconium oxide, and alumina. In various arrangements, the size of the inert filler particles is between 5 nm and 500 μm, between 10 nm and 100 μm, or any suitable size range. In other arrangements, porosity is achieved by using specific processing methods when the layers are formed. An example of such processing methods is laser ablation, in which nanometer- to micrometer-sized channels are formed in the layers. Laser ablation can additionally or optionally achieve porosity in the layers by subsurface ablation. Subsurface ablation can create voids within the layers after focusing a beam of light at a point within the layer and thus evaporating the layer material near that point. This process can be repeated to create voids throughout the layer, thereby achieving porosity in the layers. The volume of the pores is preferably determined by laser power (e.g., higher laser power corresponds to a larger pore volume), but can also be determined by the focal size of the beam or any other suitable laser parameter. Another example is mechanically piercing the layer to form a channel through it. The porosity can have any suitable distribution in the layer (e.g., uniform, increasing porosity gradient through the layer, random porosity gradient, decreasing porosity gradient through the layer, periodic porosity, etc.).

[0113] In some CRR reactions, bicarbonate ions are generated at the cathode 220. It can be useful to have a polymer somewhere between the cathode 220 and the anode 240 that blocks bicarbonate transport to prevent bicarbonate ions from migrating away from the cathode. Bicarbonate ions can carry away some CO2 during their migration, which reduces the amount of CO2 available for the reaction at the cathode. In one arrangement, the polymer electrolyte membrane 265 comprises a polymer that blocks bicarbonate transport. Examples of such polymers include, but are not limited to, those mentioned above. Formulation, GORE-SELECT (PFSA)(FuMA-Tech GmbH), and (PFSA)(Solvay). In another arrangement, an anolyte buffer layer 245 exists between the polymer electrolyte membrane 265 and the anode 240, which blocks bicarbonate transport. If the polymer electrolyte membrane is an anion conductor, or does not block bicarbonate transport, an additional anolyte buffer layer to prevent bicarbonate transport may be useful. Materials that can be used to block bicarbonate transport include, but are not limited to, those mentioned above. Formulation, GORE-SELECT (PFSA)(FuMA-Tech GmbH), and (PFSA)(Solvay). Of course, if bicarbonate is not present in the CRR, then including bicarbonate blocking features in the ion exchange layer 260 is not particularly desirable.

[0114] In another embodiment of the invention, the anode buffer layer 245 provides a region for the transition of proton concentration between the polymer electrolyte membrane 265 and the anode 240. The proton concentration in the polymer electrolyte membrane 265 depends on both its composition and the ions it conducts. For example, the proton-conducting Nafion polymer electrolyte membrane 265 has a high proton concentration. The hydroxide-conducting FumaSep FAA-3 polymer electrolyte membrane 265 has a low proton concentration. For example, if the desired proton concentration at the anode 240 differs from that at the polymer electrolyte membrane 265 by more than three orders of magnitude, the anode buffer layer 245 can be used to achieve the transition from the proton concentration of the polymer electrolyte membrane 265 to the desired proton concentration at the anode. The anode buffer layer 245 may comprise a single polymer or multiple polymers. If the anode buffer layer 245 comprises multiple polymers, the multiple polymers may be mixed together or arranged in separate, adjacent layers. Materials that can be used to provide a region for pH transition include, but are not limited to, Nafion, FumaSep FAA-3, etc. Tokuyama anion exchange polymers and polyether-based polymers, such as polyethylene oxide (PEO), blends thereof, and / or any other suitable materials. High proton concentrations are considered to be in the range of about 10 molar concentrations to 0.1 molar concentrations, and low concentrations are considered to be less than about 0.01 molar concentrations. Ion-conducting polymers can be classified into different categories based on the type of ions they conduct. This has been discussed in more detail above. There are three classes of ion-conducting polymers described in Table 4 below. In one embodiment of the invention, at least one of the ion-conducting polymers in the cathode 220, anode 240, polymer electrolyte membrane 265, cathode buffer layer 225, and anode buffer layer 245 comes from a different category than at least one of the other ion-conducting polymers.

[0115]

[0116] Some Class A ion-conducting polymers are marketed under trade names such as 2259-60 (Pall RAI), Tokuyama Co.'s AHA, etc. FAA-3 (fumatech GbbH) Solvay's Morgane ADP, or Tosoh's SF-17 anion exchange membrane material is known. Some category C ion-conducting polymers are marketed under trade names such as... (DuPont TM ), (Gore) (fumatech GmbH), and Various formulations of PFSA (Solvay) are known.

[0117] According to another embodiment of the invention, a novel membrane electrode assembly (MEA) 400 for use in CRR is... Figure 4 As shown in the diagram, MEA 400 has a cathode 420, an anode 440, and an ion-conducting polymer layer 460. The ion-conducting polymer layer 460 includes an ion-conducting polymer film 465 and a cathode buffer layer 425. The anode 440 and the ion-conducting polymer film 465 contain an ion-conducting polymer that is a cation conductor, and the ion-conducting polymer film 465 does not allow a significant amount of bicarbonate ions to reach the anode 440; therefore, an anode buffer layer is not used here.

[0118] According to yet another embodiment of the invention, a novel membrane electrode assembly (MEA) 500 for use in CRR is... Figure 5 As shown in the diagram, the MEA 500 has a cathode 520, an anode 540, and an ion-conducting polymer film 560. In this arrangement, the transition from a high proton concentration within the ion-conducting polymer film 560 to a low proton concentration in the cathode layer is achieved at the interface between the cathode layer 520 and the ion-conducting polymer film 560, thus eliminating the need for an additional buffer layer between these two layers. The ability to achieve a proton concentration difference without a buffer layer depends on the type of ion-conducting polymer used in the cathode layer 520 and the ion-conducting polymer film 560, and the manner in which the ion-conducting polymers are mixed at the interfaces of the layers.

[0119] In another specific example, the membrane electrode assembly includes: a cathode layer comprising a reduction catalyst and a first anion-conducting polymer (e.g., Sustainion, FumaSep FAA-3, Tokuyama anion exchange polymer); an anode layer comprising an oxidation catalyst and a first cationic conductive polymer (e.g., PFSA polymer); a membrane layer comprising a second cationic conductive polymer and disposed between the cathode layer and the anode layer to electrically connect the cathode layer and the anode layer; and a cathode buffer layer comprising a second anion-conducting polymer (e.g., Sustainion, FumaSep FAA-3, Tokuyama anion exchange polymer) and disposed between the cathode layer and the membrane layer to electrically connect the cathode layer and the membrane layer. In this example, the cathode buffer layer may have a porosity between about 1% and 90% by volume, but may additionally or optionally have any suitable porosity (including, for example, no porosity). In other instances, the cathode layer can have any suitable porosity (e.g., between 0.01%-95%, 0.1%-95%, 0.01%-75%, 1%-95%, 1%-90%, etc.).

[0120] In relevant examples, the membrane electrode assembly may include an anode buffer layer comprising a third cationic conductive polymer and disposed between the membrane layer and the anode layer to electrically connect the membrane layer and the anode layer. The anode buffer layer preferably has a porosity between about 1% and 90% by volume, but may additionally or optionally have any suitable porosity (including, for example, no porosity). However, in other arrangements and examples, the anode buffer layer may have any suitable porosity (e.g., between 0.01%-95%, 0.1%-95%, 0.01%-75%, 1%-95%, 1%-90%, etc.).

[0121] In another specific example, the membrane electrode assembly includes: a cathode layer comprising a reduction catalyst and a first anion-conducting polymer (e.g., Sustainion, FumaSep, Tokuyama anion exchange polymer); an anode layer comprising an oxidation catalyst and a first cationic conductive polymer; a membrane layer comprising a second anion-conducting polymer (e.g., Sustainion, FumaSep FAA-3, Tokuyama anion exchange polymer) and disposed between the cathode layer and the anode layer to conductively connect the cathode layer and the anode layer; and an anode buffer layer comprising a second cationic conductive polymer and disposed between the anode layer and the membrane layer to conductively connect the anode layer and the membrane layer.

[0122] In relevant examples, the membrane electrode assembly may include a cathode buffer layer comprising a third anionic conductive polymer and disposed between the cathode layer and the membrane layer to electrically connect the cathode layer and the membrane layer. The third anionic conductive polymer may be the same as or different from the first anionic conductive polymer and / or the second anionic conductive polymer. The cathode buffer layer preferably has a porosity between about 1% and 90% by volume, but may additionally or optionally have any suitable porosity (including, for example, no porosity). However, in other arrangements and examples, the cathode buffer layer may have any suitable porosity (e.g., between 0.01%-95%, 0.1%-95%, 0.01%-75%, 1%-95%, 1%-90%, etc.).

[0123] The porosity of the examples and other examples and variations described above (e.g., the porosity of cathode buffer layers, anode buffer layers, membrane layers, cathode layers, anode layers, other suitable layers, etc.) preferably has a uniform distribution, but may additionally or optionally have any suitable distribution (e.g., random distribution, increasing pore size gradient across or across the layer, decreasing pore size gradient across or across the layer, etc.). Porosity can be formed by any suitable mechanism, such as inert filler particles (e.g., diamond particles, boron-doped diamond particles, polyvinylidene fluoride / PVDF particles, polytetrafluoroethylene / PTFE particles, etc.) and any other suitable mechanism for forming substantially non-reactive regions within the polymer layer. Inert filler particles may have any suitable size, such as a minimum of about 10 nanometers and a maximum of about 200 nanometers, and / or any other suitable size or size distribution.

[0124] CO x Reduction Reactor (CRR)

[0125] Figure 6 CO is shown according to an embodiment of the present invention. x A schematic diagram of the main components of the reduction reactor (CRR) 605.

[0126] CRR 605 has the features described above. Figure 2 The membrane electrode assembly 600 is described. The membrane electrode assembly 600 has a cathode 620 and an anode 640 separated by an ion exchange layer 660. The ion exchange layer 660 may include three sublayers: a cathode buffer layer 625, a polymer electrolyte membrane 665, and optionally an anode buffer layer 645. Furthermore, the CRR 605 has a cathode support structure 622 adjacent to the cathode 620 and an anode support structure 642 adjacent to the anode 640.

[0127] In one embodiment of the invention, the cathode 620 comprises an ion-conducting polymer as described in Category A of Table 4 above, the anode 640 comprises an ion-conducting polymer as described in Category C of Table 4 above, and the polymer electrolyte membrane 665 comprises an ion-conducting polymer as described in Category C of Table 4 above. In one arrangement, the cathode buffer layer 625 comprises at least two ion-conducting polymers: one as described in Category A of Table 4 above, and one as described in Category B of Table 4 above.

[0128] In another embodiment of the invention, cathode 620 comprises both an ion-conducting polymer as described in Category A and an ion-conducting polymer as described in Category B, anode 640 comprises an ion-conducting polymer as described in Category C, polymer electrolyte membrane 665 comprises an ion-conducting polymer as described in Category A, cathode buffer layer 625 comprises both an ion-conducting polymer as described in Category A and an ion-conducting polymer as described in Category B, and anode buffer layer 645 comprises an ion-conducting polymer as described in Category C. Other combinations of ion-conducting polymers are also possible.

[0129] The cathode support structure 622 has a cathode plate 624, typically made of graphite, to which a voltage can be applied. Flow channels, such as serpentine channels, may be present within the inner surface of the cathode plate 624. A cathode gas diffusion layer 626 is also present adjacent to the inner surface of the cathode plate 624. In some arrangements, more than one cathode gas diffusion layer (not shown) is present. The cathode gas diffusion layer 626 facilitates gas inflow and outflow from the membrane electrode assembly 600. An example of the cathode gas diffusion layer 626 is carbon paper with a carbon microporous layer.

[0130] The anode support structure 642 has an anode plate 644, typically made of metal, to which a voltage can be applied. Flow channels, such as serpentine channels, may be present within the inner surface of the anode plate 644. An anode gas diffusion layer 646 is also present adjacent to the inner surface of the anode plate 644. In some arrangements, more than one anode gas diffusion layer (not shown) is present. The anode gas diffusion layer 646 facilitates gas inflow and outflow from the membrane electrode assembly 600. Examples of the anode gas diffusion layer 646 are titanium mesh or titanium felt. In some arrangements, the gas diffusion layers 626, 646 are microporous.

[0131] There are also inlets and outlets (not shown) associated with support structures 622 and 642, which allow reactants and products to flow to membrane electrode assembly 600, respectively. Various gaskets (not shown) are also present to prevent reactants and products from leaking from the cell.

[0132] In one embodiment of the invention, a direct current (DC) voltage is applied to the membrane electrode assembly 600 through a cathode plate 624 and an anode plate 642. Water is supplied to the anode 640 and oxidized by an oxidation catalyst to form molecular oxygen (O2), releasing protons (H+) and electrons (e-). Protons migrate toward the cathode 620 through the ion exchange layer 660. Electrons flow through an external circuit (not shown). In one embodiment of the invention, the reaction is described as follows:

[0133] 2H₂O---4H + +4e - +O

[0134] In other embodiments of the invention, additional reactants may be supplied to the anode 640, and additional reactions may occur. Some of these reactants are listed in Table 3 above.

[0135] According to an embodiment of the invention, the flow of reactants, products, ions, and electrons through the CRR 705 reactor is... Figure 7 The diagram in the middle is shown.

[0136] CRR 705 has the features described above. Figure 2 The membrane electrode assembly 700 is described. The membrane electrode assembly 700 has a cathode 720 and an anode 740 separated by an ion exchange layer 760. The ion exchange layer 760 may include three sublayers: a cathode buffer layer 725, a polymer electrolyte membrane 765, and an optional anode buffer layer 745. Furthermore, the CRR 705 has a cathode support structure 722 adjacent to the cathode 720 and an anode support structure 742 adjacent to the anode 740.

[0137] The cathode support structure 722 has a cathode plate 724, typically made of graphite, to which a voltage can be applied. Flow channels, such as serpentine channels, may be present within the inner surface of the cathode plate 724. A cathode gas diffusion layer 726 is also present adjacent to the inner surface of the cathode plate 724. In some arrangements, more than one cathode gas diffusion layer (not shown) is present. The cathode gas diffusion layer 726 facilitates gas inflow and outflow from the membrane electrode assembly 700. An example of the cathode gas diffusion layer 726 is carbon paper with a carbon microporous layer.

[0138] The anode support structure 742 has an anode plate 744, typically made of metal, to which a voltage can be applied. Flow channels, such as serpentine channels, may be present within the inner surface of the anode plate 744. An anode gas diffusion layer 746 is also present adjacent to the inner surface of the anode plate 744. In some arrangements, more than one anode gas diffusion layer (not shown) is present. The anode gas diffusion layer 746 facilitates gas inflow and outflow from the membrane electrode assembly 700. Examples of the anode gas diffusion layer 746 are titanium mesh or titanium felt. In some arrangements, the gas diffusion layers 726, 746 are microporous.

[0139] Inlets and outlets associated with support structures 722 and 742 may also be present, allowing reactants and products to flow to the membrane electrode assembly 700, respectively. Various gaskets may also be present to prevent reactants and products from leaking out of the battery.

[0140] CO x It can be supplied to the cathode 720 and, in the presence of protons and electrons, undergo CO2 treatment. x Reduction catalyst reduction. CO x It can be supplied to the cathode 720 at pressures between 0 psig and 1000 psig, or any other suitable range. CO x It can be supplied to the cathode 720 at a concentration below 100% or any other suitable percentage mixed with other gases. In some arrangements, CO x The concentration can be as low as about 0.5%, as low as 5%, or as low as 20% or any other suitable percentage.

[0141] In one embodiment of the invention, between approximately 10% and 100% of the unreacted CO x The product is collected at the outlet adjacent to cathode 720, separated from the reduction reaction products, and then recycled back to the inlet adjacent to cathode 720. In one embodiment of the invention, the oxidation products at anode 740 are compressed to a pressure between 0 psig and 1500 psig.

[0142] In one embodiment of the invention, multiple CRRs (e.g.) Figure 6 The CRRs shown are arranged in an electrochemical stack and operate together. The individual electrochemical cells constituting the stack can be electrically connected in series or parallel. Reactants are supplied to the individual CRRs, and the reaction products are then collected.

[0143] The main inputs and outputs of the reactor are in Figure 8 As shown in the image. CO x Anode feed material and electricity are fed into the reactor. CO x Reduction products and any unreacted CO xExit the reactor. Unreacted CO x It can be separated from the reduction products and recycled back to the reactor inlet side. Anodizing products and any unreacted anode feed material leave the reactor as a separate stream. Unreacted anode feed material can be recycled back to the reactor inlet side.

[0144] Various catalysts in the cathode of the CRR cause CO to be produced. x The reduction reaction forms different products or a mixture of products. Possible CO at the cathode. x Examples of reduction reactions are described below:

[0145] CO2 + 2H + +2e - →CO + H₂O

[0146] 2CO2 + 12H + +12e - →CH2CH2+4H2O

[0147] 2CO2 + 12H + +12e - →CH3CH2OH+3H2O

[0148] CO2 + 8H + +8e + →CH4+2H2O

[0149] 2CO + 8H + +8e - →CH2CH2+2H2O

[0150] 2CO + 8H + +8e - →CH3CH2OH+H2O

[0151] CO+6H + +8e - →CH4+H2O

[0152] In another embodiment of the invention, operation of CO is provided. x The method for the reduction reactor is as described above in the embodiments of the present invention. The method involves applying a DC voltage to a cathode plate and an anode plate, supplying an oxidation reactant to the anode and allowing an oxidation reaction to occur, supplying a reduction reactant to the cathode and allowing a reduction reaction to occur, collecting oxidation reaction products from the anode, and collecting reduction reaction products from the cathode.

[0153] In one arrangement, the DC voltage is greater than -1.2V. In various arrangements, the oxidizing agent can be any one of hydrogen, methane, ammonia, water, or combinations thereof, and / or any other suitable oxidizing agent. In one arrangement, the oxidizing agent is water. In various arrangements, the reducing agent can be any one of carbon dioxide, carbon monoxide, or combinations thereof, and / or any other suitable reducing agent. In one arrangement, the reducing agent is carbon dioxide.

[0154] In another specific instance, CO xThe reduction reactor includes a membrane electrode assembly comprising a cathode layer containing a reduction catalyst and a first anion-conducting polymer (e.g., FumaSep FAA-3, Sustainion, Tokuyama anion exchange polymer). The reactor also includes an anode layer containing an oxidation catalyst and a first cationic conductive polymer (e.g., Nafion 324, Nafion 350, Nafion 417, Nafion 424, Nafion 438, Nafion 450, Nafion 521, Nafion 551, other Nafion formulations, Aquivion, GORE-SELECT, Flemion, PSFA, etc.). The reactor further includes a membrane layer containing a second cationic conductive polymer, wherein the membrane layer is disposed between and electrically connects the cathode and anode layers. The reactor also includes a cathode manifold coupled to the cathode layer and an anode manifold coupled to the anode layer. In this example, the cathode manifold may include a cathode support structure adjacent to the cathode layer, wherein the cathode support structure includes a cathode plate, a cathode gas diffusion layer disposed between the cathode plate and the cathode layer, a first inlet fluidly connected to the cathode gas diffusion layer, and a first outlet fluidly connected to the cathode gas diffusion layer. Similarly, in this example, the anode manifold may include an anode support structure adjacent to the anode layer, wherein the anode support structure includes an anode plate, an anode gas diffusion layer disposed between the anode plate and the anode layer, a second inlet fluidly connected to the anode gas diffusion layer, and a second outlet fluidly connected to the anode gas diffusion layer. In a related example, the membrane electrode assembly of the reactor includes a cathode buffer layer comprising a second anion-conducting polymer (e.g., FumaSep FAA-3, Sustainion, Tokuyama anion exchange polymer), disposed between the cathode layer and the membrane layer and electrically connecting the cathode layer and the membrane layer. The buffer layer in this example (e.g., a cathode buffer layer, an anode buffer layer) may have a porosity between about 1% and 90% by volume, but may optionally have any suitable porosity (including, for example, no porosity). However, in other arrangements and examples, the buffer layer may have any suitable porosity (e.g., between 0.01%-95%, 0.1%-95%, 0.01%-75%, 1%-95%, 1%-90%, etc.). In related examples, the first and second anion-conducting polymers of the membrane electrode assembly may be the same anion-conducting polymer (e.g., containing the same polymer formulation).

[0155] This invention has been described herein in considerable detail to provide those skilled in the art with information relating to the application of novel principles and the construction and use of such specialized components as required. However, it should be understood that the invention can be embodied in various devices, materials, and apparatuses, and various modifications can be made to both the devices and operating procedures without departing from the scope of the invention itself.

Claims

1. A method for operating CO x Methods for reducing reactors include: Provide CO x Reduction reactor, the CO x The reduction reactor includes: ● Membrane electrode assembly, the membrane electrode assembly comprising: o Cathode layer, the cathode layer comprising a reduction catalyst and a first anion-conducting polymer; o Anode layer, the anode layer comprising an oxidation catalyst and a first cationic conductive polymer; o A film layer comprising a second cationic conductive polymer, the film layer being disposed between the cathode layer and the anode layer and conductively connecting the cathode layer and the anode layer; and o A cathode buffer layer comprising a second anion-conductive polymer, wherein the cathode buffer layer is disposed between the cathode layer and the film layer and conductively connects the cathode layer and the film layer, and wherein the cathode buffer layer is porous; ● A cathode manifold coupled to the cathode layer, wherein the cathode manifold includes a cathode plate; ● An anode manifold coupled to the anode layer, wherein the anode manifold includes an anode plate; A voltage is applied to the cathode plate and the anode plate; Supplying one or more oxidizing reactants to the anode layer and allowing oxidation to occur; supplying one or more reducing reactants selected from carbon monoxide (CO), carbon dioxide (CO2), and combinations thereof and allowing reduction to occur to produce one or more reduction products; and The one or more reduction reaction products are discharged from the cathode manifold.

2. The method according to claim 1, wherein the one or more reduction reaction products comprise one or more of the following: carbon monoxide, syngas, methane, ethylene, formic acid, methanol, glyoxal, acetic acid, hydroxyacetaldehyde, ethylene glycol, acetaldehyde; ethanol, hydroxyacetone, acetone, allyl alcohol, propanal; and n-propanol.

3. The method of claim 1, wherein the applied voltage is greater than -1.2 V.

4. The method according to claim 1, wherein the one or more oxidizing reactants are selected from hydrogen, methane, ammonia, water, or combinations thereof.

5. The method of claim 1, wherein the membrane is non-porous and prevents reactants and products from the cathode from being transferred to the anode.

6. The method according to claim 1, wherein the cathode layer comprises particles of the reduction catalyst and a blend of the first anionic conductive polymer.

7. The method of claim 6, wherein the first anionic conductive polymer reduces hydrogen formation reactions.

8. The method according to claim 1, wherein the first anionic conductive polymer comprises between 10 wt% and 90 wt% of the cathode layer.

9. The method according to claim 1, wherein the first anionic conductive polymer comprises between 20 wt% and 80 wt% of the cathode layer.

10. A type of CO x The reduction reactor includes: Membrane electrode assembly, the membrane electrode assembly comprising: ● A cathode layer comprising a reduction catalyst and a first anion-conducting polymer; ● An anode layer comprising an oxidation catalyst and a first cationic conductive polymer; ● A membrane layer comprising a second cationic conductive polymer, the membrane layer being disposed between the cathode layer and the anode layer and conductively connecting the cathode layer and the anode layer; and ● A cathode buffer layer comprising a second anion-conducting polymer, wherein the cathode buffer layer is disposed between the cathode layer and the film layer and conductively connects the cathode layer and the film layer, and wherein the cathode buffer layer is porous; A cathode manifold, the cathode manifold being coupled to the cathode layer; and An anode manifold, which is coupled to the anode layer. The CO x Selected from carbon monoxide (CO), carbon dioxide (CO2), and combinations thereof.

11. The CO according to claim 10 x A reduction reactor, wherein the cathode manifold includes a cathode support structure adjacent to the cathode layer, the cathode support structure including a cathode plate.

12. The CO according to claim 10 x The reduction reactor, wherein the cathode support structure further includes: A cathode gas diffusion layer is disposed between the cathode plate and the cathode layer; A first inlet, which is fluidly connected to the cathode gas diffusion layer; And a first outlet, which is fluidly connected to the cathode gas diffusion layer.

13. The CO according to claim 10 x A reduction reactor, wherein the membrane is non-porous to prevent reactants and products from the cathode from being transferred to the anode.

14. The CO according to claim 10 x A reduction reactor, wherein the cathode layer comprises particles of the reduction catalyst and a blend of the first anionic conductive polymer.

15. The CO according to claim 14 x A reduction reactor, wherein the first anionic conductive polymer reduces the hydrogen formation reaction.

16. The CO according to claim 10 x A reduction reactor, wherein the first anionic conductive polymer comprises between 10 wt% and 90 wt% of the cathode layer.

17. The CO according to claim 10 x A reduction reactor, wherein the first anionic conductive polymer comprises between 20 wt% and 80 wt% of the cathode layer.

18. A membrane electrode assembly configured to reduce CO. x To produce CO x The reduction product, the membrane electrode assembly includes: A cathode layer comprising a reduction catalyst configured to reduce CO x To produce CO x Reduction products; Anode layer, the anode layer comprising an oxidation catalyst; A membrane layer comprising a first cationic conductive polymer, the membrane layer being disposed between the cathode layer and the anode layer, the membrane layer being electrically connected to the cathode layer and the anode layer; as well as A cathode buffer layer comprising a first anion-conductive polymer, wherein the cathode buffer layer is disposed between the cathode layer and the film layer and electrically connects the cathode layer and the film layer, wherein the cathode buffer layer is porous to allow gas to pass through the cathode buffer layer, and wherein the film layer is non-porous to prevent gas from passing between the cathode layer and the anode layer. The CO x Selected from carbon monoxide (CO), carbon dioxide (CO2), and combinations thereof.

19. The membrane electrode assembly of claim 18, further comprising an anode buffer layer comprising a second cationic conductive polymer, the anode buffer layer being disposed between the membrane layer and the anode layer.

20. The membrane electrode assembly of claim 18, wherein the cathode layer further comprises a second anion-conducting polymer.

21. The membrane electrode assembly of claim 18, wherein the anode layer further comprises a second cationic conductive polymer.

22. The membrane electrode assembly of claim 18, wherein the thickness of the cathode buffer layer is between 200 nm and 100 µm.

23. The membrane electrode assembly of claim 20, wherein the cathode layer comprises particles of the reduction catalyst and a blend of the first anionic conductive polymer.

24. The membrane electrode assembly of claim 23, wherein the first anionic conductive polymer reduces hydrogen formation reactions.

25. The membrane electrode assembly according to any one of claims 18-24, wherein the membrane electrode assembly comprises a catalyst composition, the catalyst composition comprising: Conductive carrier; First catalyst particles, the first catalyst particles being loaded on the conductive support; and The second catalyst particle is loaded on the conductive support, wherein the first catalyst particle and the second catalyst particle are made of different materials, and wherein the first catalyst particle and the second catalyst particle catalyze CO. x reduction.

26. The membrane electrode assembly of claim 25, wherein the first catalyst particles and the second catalyst particles have different morphologies.

27. The membrane electrode assembly of claim 26, wherein the first catalyst particles are selected from one of the following: V, Cr, Mn, Fe, Co, Ni, Cu, Sn, Zr, Nb, Mo, Au, Ru, Rh, Pd, Ag, Cd, Hf, Ta, W, Re, Ir, Pt, Hg, Al, Si, In, Ga, Tl, Pb, Bi, Sb, Te, Sm, Tb, Ce, and Nd.

28. The membrane electrode assembly of claim 27, wherein the second catalyst particle is selected from one of the following, which is different from the first catalyst particle: V, Cr, Mn, Fe, Co, Ni, Cu, Sn, Zr, Nb, Mo, Au, Ru, Rh, Pd, Ag, Cd, Hf, Ta, W, Re, Ir, Pt, Hg, Al, Si, In, Ga, Tl, Pb, Bi, Sb, Te, Sm, Tb, Ce, and Nd.

29. The membrane electrode assembly of claim 25, wherein the first catalyst particle is gold and the second catalyst particle is copper.

30. The membrane electrode assembly of claim 25 further comprises one or more additional catalyst particles having the same material as the first catalyst particles.

31. The membrane electrode assembly of claim 30 further comprises one or more additional catalysts having the same material as the second catalyst particles.

32. A type of CO x The reduction reactor includes: ● Membrane electrode assembly, the membrane electrode assembly comprising: o A cathode layer comprising a reduction catalyst configured to reduce CO x ; o Anode layer, the anode layer comprising an oxidation catalyst; o A film layer comprising a first cationic conductive polymer, the film layer being disposed between the cathode layer and the anode layer, the film layer electrically connecting the cathode layer and the anode layer; and o A cathode buffer layer comprising a first anion-conductive polymer, wherein the cathode buffer layer is disposed between the cathode layer and the film layer and conductively connects the cathode layer and the film layer, wherein the cathode buffer layer is porous to allow gas to pass through the cathode buffer layer and wherein the film layer is non-porous to prevent gas from passing between the cathode layer and the anode layer; ● A cathode manifold, said cathode manifold being coupled to the cathode layer; and ● Anode manifold, which is coupled to the anode layer. The CO x Selected from carbon monoxide (CO), carbon dioxide (CO2), and combinations thereof.

33. The CO according to claim 32 x A reduction reactor, wherein the cathode manifold includes a cathode support structure adjacent to the cathode layer, the cathode support structure comprising: ● Cathode plate; ● A cathode gas diffusion layer, wherein the cathode gas diffusion layer is disposed between the cathode plate and the cathode layer; ● A first inlet, which is fluidly connected to the cathode gas diffusion layer; as well as ● A first outlet, which is fluidly connected to the cathode gas diffusion layer; and The anode manifold includes an anode support structure adjacent to the anode layer, the anode support structure comprising: ● Anode plate; ● An anode gas diffusion layer, wherein the anode gas diffusion layer is disposed between the anode plate and the anode layer; ● A second inlet, which is fluidly connected to the anode gas diffusion layer; and ● Second outlet, which is fluidly connected to the anode gas diffusion layer.

34. A type of CO x Restoration methods include: Provide CO according to claim 32 x Reduction reactor, Apply a voltage to the cathode manifold and the anode manifold; The anode layer is supplied with one or more oxidizing reactants and oxidation is permitted to occur; one or more reducing reactants selected from carbon monoxide (CO), carbon dioxide (CO2), and combinations thereof are supplied and reduction is permitted to occur to produce one or more reduction products selected from: carbon monoxide, syngas, methane, ethylene, formic acid, methanol, glyoxal, acetic acid, hydroxyacetaldehyde, ethylene glycol, acetaldehyde; ethanol, hydroxyacetone, acetone, allyl alcohol, propionaldehyde; and n-propanol; and The one or more reduction reaction products are discharged from the cathode manifold.

35. A membrane electrode assembly, comprising: A cathode layer comprising the catalyst composition according to claim 25 and a first anionic conductive polymer; An anode layer comprising an oxidation catalyst and a first cationic conductive polymer; A membrane layer comprising a second cationic conductive polymer, the membrane layer being disposed between the cathode layer and the anode layer and electrically connecting the cathode layer and the anode layer; And a cathode buffer layer comprising a second anion-conducting polymer, wherein the cathode buffer layer is disposed between the cathode layer and the film layer and conductively connects the cathode layer and the film layer, and wherein the cathode buffer layer is porous.

36. A type of CO x The reduction reactor includes the membrane electrode assembly of claim 35, and further includes a cathode manifold coupled to the cathode layer; and an anode manifold coupled to the anode layer.

37. The CO according to claim 36 x A reduction reactor, wherein the cathode manifold includes a cathode support structure adjacent to the cathode layer, the cathode support structure comprising: ● Cathode plate; ● A cathode gas diffusion layer, wherein the cathode gas diffusion layer is disposed between the cathode plate and the cathode layer; ● A first inlet, which is fluidly connected to the cathode gas diffusion layer; as well as ● A first outlet, which is fluidly connected to the cathode gas diffusion layer; and The anode manifold includes an anode support structure adjacent to the anode layer, the anode support structure comprising: ● Anode plate; ● An anode gas diffusion layer, wherein the anode gas diffusion layer is disposed between the anode plate and the anode layer; ● A second inlet, which is fluidly connected to the anode gas diffusion layer; and ● Second outlet, which is fluidly connected to the anode gas diffusion layer.

38. A membrane electrode assembly, comprising: ● A cathode layer comprising a reduction catalyst and a first anion-conducting polymer; ● An anode layer comprising an oxidation catalyst and a first cationic conductive polymer; ● A film layer comprising a second anionic conductive polymer, the film layer being disposed between the cathode layer and the anode layer, the film layer being electrically connected to the cathode layer and the anode layer; ● An anode buffer layer comprising a second cationic conductive polymer, wherein the anode buffer layer is disposed between the anode layer and the film layer and conductively connects the anode layer and the film layer; as well as ● A cathode buffer layer having a second porosity between 0.01% and 95% by volume, the cathode buffer layer comprising a third anionic conductive polymer, wherein the cathode buffer layer is disposed between the cathode layer and the film layer and electrically connects the cathode layer and the film layer.

39. The membrane electrode assembly of claim 38, wherein the membrane layer has a first porosity between 0.01% and 95% by volume.

40. A type of CO x A reduction reactor, comprising the membrane electrode assembly of claim 38, and further comprising a cathode manifold coupled to the cathode layer; and an anode manifold coupled to the anode layer, wherein the CO x Selected from carbon monoxide (CO), carbon dioxide (CO2), and combinations thereof.

41. The CO according to claim 40 x A reduction reactor, wherein the cathode manifold includes a cathode support structure adjacent to the cathode layer, the cathode support structure comprising: ● Cathode plate; ● A cathode gas diffusion layer, wherein the cathode gas diffusion layer is disposed between the cathode plate and the cathode layer; ● A first inlet, which is fluidly connected to the cathode gas diffusion layer; as well as ● A first outlet, which is fluidly connected to the cathode gas diffusion layer; and The anode manifold includes an anode support structure adjacent to the anode layer, the anode support structure comprising: ● Anode plate; ● An anode gas diffusion layer, wherein the anode gas diffusion layer is disposed between the anode plate and the anode layer; ● A second inlet, which is fluidly connected to the anode gas diffusion layer; and ● Second outlet, which is fluidly connected to the anode gas diffusion layer.

42. A type of CO x Restoration methods include: Provide CO according to claim 40 x Reduction reactor, Apply a voltage to the cathode manifold and the anode manifold; The anode layer is supplied with one or more oxidizing reactants and oxidation is permitted to occur; one or more reducing reactants selected from carbon monoxide (CO), carbon dioxide (CO2), and combinations thereof are supplied and reduction is permitted to occur to produce one or more reduction products selected from: carbon monoxide, syngas, methane, ethylene, formic acid, methanol, glyoxal, acetic acid, hydroxyacetaldehyde, ethylene glycol, acetaldehyde; ethanol, hydroxyacetone, acetone, allyl alcohol, propionaldehyde; and n-propanol; and The one or more reduction reaction products are discharged from the cathode manifold.

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