Electrolytic cell system and electrode manufacturing method

Abstract

Electrolyzer system and electrode manufacturing method. The electrolyzer system may include a first vessel in communication with the electrolyzer stack, a power source, an electrode, a separator, a membrane, and a second vessel in communication with the electrolyzer stack. The electrode may have a catalytic material and a microporous structure and / or a nanoporous structure. The electrode manufacturing method may include providing a substrate, contacting the substrate with an acidic solution, applying a current to the substrate, simultaneously depositing a support material and a base material, including a roughened material, on the substrate, and subjecting the roughened material to a leaching process.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to and the benefit of Singapore Patent Application No. 10202108014T, entitled "Novel SunGreenH2 Electrolyser System," filed on July 22, 2021, the specification, claims and drawings of which are incorporated herein by reference.

[0002] Embodiments of the present invention relate to electrolyzer systems that produce gaseous hydrogen using an anode, a cathode, and / or an ion exchange membrane separating the anode and cathode, and that are powered by renewable energy sources such as solar, wind, hydro, bioenergy, and geothermal energy. [Background technology]

[0003] Hydrogen is a key part of any discussion on sustainability and emissions reduction across the major energy sectors. In addition to being a feedstock and process gas for many industrial processes, hydrogen is emerging as a fuel alternative for transportation applications. Renewable hydrogen resources are therefore required to increase production capacity. Low-temperature electrolysis of water is currently the most mature method for carbon-free hydrogen production and is reaching a relevant scale that will impact the energy landscape. However, the costs of low-temperature electrolysis of water still need to be reduced to make it economical with traditional sources of hydrogen production. The availability of low-cost renewable energy sources would allow for reduced operating costs, and the potential exists for significant reductions in capital costs with material and manufacturing optimization.

[0004] Challenges for hydrogen production by electrolyzer systems include the stability of the electrolyzer system and the high cost of electrode materials. Research efforts are underway to improve the electrocatalytic activity of platinum group metals (PGM) based catalysts. Other research efforts include reducing the PGM loading or completely eliminating PGMs by developing non-PGM electrocatalysts. What is needed is a way to reduce the power load for hydrogen production and reduce the cost of electrode materials while maintaining or increasing their efficacy. Summary of the Invention [Means for solving the problem]

[0005] The present system and method relates to an electrolyzer system for producing hydrogen and a method for producing hydrogen using an electrolyzer system. In particular, the present system and method relates to a system for electrolyzing a solution, the system including a first vessel in communication with at least one electrolyzer stack including a compound including at least one catalytic material and at least one electrode having a microporous structure and at least one separator, and a second vessel in communication with the at least one electrolyzer stack.

[0006] In another embodiment, the at least one catalytic material comprises a PGM. In another embodiment, the at least one catalytic material comprises iron. In another embodiment, the electrolytic cell system further comprises at least one membrane. In another embodiment, the at least one electrode further comprises a scarifying material. In another embodiment, the roughening material comprises aluminum. In another embodiment, the at least one electrode further comprises a nanoporous structure. In another embodiment, the at least one electrode further comprises at least one dopant.

[0007] In one embodiment, the method of the present invention relates to a method for splitting water in a solution, the method comprising: passing a solution comprising at least one nitrogen compound through at least one electrolytic cell stack, contacting the solution with at least one electrode comprising at least one catalytic material and a microporous structure, splitting water molecules in the solution to produce hydrogen gas and nitrogen gas or oxygen gas, separating the oxygen gas or nitrogen gas and hydrogen gas, exhausting the hydrogen gas from the at least one electrolytic cell stack, and collecting the hydrogen gas. In another embodiment, the method further comprises applying an electric current to the electrodes.

[0008] In one embodiment, the method of the present invention is a method for manufacturing an electrode, comprising providing a substrate, cleaning the substrate, contacting the substrate with an acidic solution, applying a current to the substrate, drying or rinsing the substrate, simultaneously depositing at least one support material and at least one base material, comprising a roughened material, on the substrate, and subjecting the at least one roughened material deposited on the substrate to a leaching process. In another embodiment, the base material comprises nickel. In another embodiment, the support material comprises aluminum. In another embodiment, the support material comprises a dopant. In another embodiment, depositing the at least one material comprises physical deposition. In another embodiment, depositing at least one material comprises chemical deposition.

[0009] In one embodiment, the system of the present invention relates to a method for fabricating an electrode, the electrode comprising a substrate and a porous structure in contact with the substrate, the porous structure comprising a host material, a support material, and pores having a diameter sufficient to accommodate atoms of the support material and dopants. In another embodiment, the porous structure comprises micropores. In another embodiment, the porous structure comprises nanopores. In another embodiment, the host material and the support material comprise at least 25% of the weight of the substrate.

[0010] The objects, advantages, novel features and further scope of the present invention will be set forth in part in the following detailed description taken in conjunction with the accompanying drawings, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by the practice of the invention. The objects and advantages of the present invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims. [Brief description of the drawings]

[0011] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate one or more embodiments of the invention and, together with the description, serve to explain the principles of the invention. The drawings are only for the purpose of illustrating one or more embodiments of the invention and are not to be construed as limiting the invention. In the following drawings:

[0012] [Figure 1] FIG. 1 illustrates one embodiment of an electrolyzer system.

[0013] [Diagram 2] FIG. 1 illustrates an embodiment of an electrolyzer stack.

[0014] [Diagram 3] FIG. 1 illustrates an embodiment of a single cell ion exchange electrolyzer.

[0015] [Figure 4] FIG. 1 illustrates an embodiment of a bipolar plate.

[0016] [Figure 5A] FIG. 1 illustrates an embodiment of an electrolyzer cell with an applied magnetic field.

[0017] [Figure 5B] 5B is a graph showing the direction of current flow and magnetic field in the electrolyzer cell shown in FIG. 5A.

[0018] [Figure 6A]FIG. 1 illustrates one embodiment of a photoelectrochemical system layout.

[0019] [Figure 6B] FIG. 1 illustrates one embodiment of a photoelectrochemical system layout.

[0020] [Figure 7] FIG. 1 is a process flow diagram of one embodiment of electrode fabrication using sputtering or electroplating.

[0021] [Figure 8] FIG. 1 is a process flow diagram of one embodiment of electrode fabrication.

[0022] [Figure 9] 1 is a series of graphs showing the initial performance and current density of a novel membrane electrode assembly ("MEA") of the present invention compared to a commercially available MEA.

[0023] [Figure 10] 1 is a series of graphs showing the initial performance and long term stability of the novel MEAs of the present invention compared to commercially available MEAs.

[0024] [Figure 11] 1 is a series of graphs illustrating the effect of selective etching of roughening and / or leaching of material from the cathode and anode.

[0025] [Figure 12] 1 is a series of graphs illustrating the effect of heat treating cathodes and anodes.

[0026] [Figure 13] 1 is a series of photographs showing the microporous structure formed by roughening and / or leaching material from the cathode and / or anode.

[0027] [Figure 14]1 is a graph showing the long term stability of a nitrogen assisted electrolyser. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] Detailed Description of the Invention The present invention is an electrolyzer system that may include bipolar plates, current collectors, separators, electrodes having catalytic materials and microporous structures, and MEA / ion exchange membranes.

[0029] The term "metal" or "metals" is defined in this specification, claims, and drawings as a compound, mixture, or material that contains a metal atom. The term "metal" or "metals" includes, but is not limited to, a metal hydroxide, a metal oxide, a metal salt, an elemental metal, a metal ion, a non-ionic metal, a mineral, or a combination thereof.

[0030] The terms "catalyst" or "catalytic material" are intended to be used interchangeably in this specification, claims, and drawings. The terms "separator" and "bipolar plate" are intended to be used interchangeably in this specification, claims, and drawings.

[0031] The term "leaching" is defined herein and in the claims as a process used to release, extract, liberate, or remove one or more metals from a material.

[0032] The terms "microporous" or "microstructured" are defined in this specification, claims, and drawings as a material in which at least a portion of the material contains pores less than one millimeter in diameter.

[0033] The terms "nanoporous" or "nanostructured" are defined in this specification, claims, and drawings as materials in which at least a portion of the material contains pores less than 1 micron in diameter.

[0034] The terms "tank" or "vessel" are used interchangeably in this specification, claims, and drawings and are defined as holders, chambers, containers, receptacles, and / or other objects capable of containing a fluid. The terms are intended to encompass holders, chambers, containers, receptacles, and / or other objects of suitable size or material. For example, they may include large acid-resistant tanks or vessels for commercial-scale water electrolysis.

[0035] The term "platinum group metal" includes, but is not limited to, platinum, palladium, rhodium, ruthenium, iridium, osmium, or combinations thereof.

[0036] The electrolyzer system can split water into hydrogen and oxygen, or nitrogen compounds into hydrogen and nitrogen, at lower voltages than conventional electrolyzers. The electrolyzer system can have higher electrode or MEA efficiency and long-term stability than conventional electrolyzers.

[0037] The present electrolyser system is capable of achieving high cell current densities with reduced PGM requirements, in particular the present electrolyser system requires less PGMs compared to conventional electrolysers using PEM technology and no PGMs compared to conventional electrolysers using AEM and AE technology.

[0038] Electrolyzer systems using nitrogen-assisted hydrogen generation do not generate oxygen, so O 2 Gas and H 2There is no risk of explosion caused by mixing with gas. The performance stability of the electrolyzer system using nitrogen-assisted hydrogen generation can be higher than that of conventional water splitting systems, especially in long-term operation. By replacing the anodic reaction at the nitrogen anode with oxygen, the electrolyzer system can be operated at lower or zero voltage, and the oxidation and corrosion of the anode caused by the presence of oxygen is avoided, i.e., nitrogen is generated instead of oxygen generation. The electrolyzer system using nitrogen-assisted hydrogen generation can have a higher stability range (e.g., at least 100 hours of continuous operation with performance changes) than the electrolyzer system using water to generate hydrogen.

[0039] Referring now to the drawings, Figure 1 shows an electrolyzer system 10. A water tank 12 may provide a water flow 14 to a positive end 18 of an electrolyzer stack 16. The electrolyzer stack 16 may be powered by a power source 20 connected to the positive end 18 and the negative end 22. Electrons may flow along a path 24 in the electrolyzer stack 16 and may split water into molecular oxygen and molecular hydrogen. Oxygen may exit the electrolyzer stack 16 via effluent 26 and hydrogen may exit the electrolyzer stack 16 via effluent 28. The hydrogen may be collected in a hydrogen storage tank 30.

[0040] 2 illustrates the electrolyzer stack 16 with an exploded view of a single electrolyzer cell 42. The individual electrolyzer cells may be held together in a stack by connectors 32. The single electrolyzer cell 34 may include electrodes 38 disposed at least partially between separators and / or bipolar plates 36. A membrane 40 may be disposed at least partially between the electrodes 38. Hydrogen 27 and oxygen 25 may be produced at the separators and / or bipolar plates 36 and may exit the single electrolyzer cell 34 at either end of the single electrolyzer cell 34.

[0041] FIG. 3 illustrates a single cell ion exchange electrolyzer 42. The membrane 40 may be at least partially disposed between gaskets 52. The membrane 40 may include an ion exchange membrane 56, an oxygen evolution reaction ("OER") catalyst 58, and a hydrogen evolution reaction ("HER") catalyst 60. The OER catalyst 58 and the HER catalyst 60 may include gas diffusion layers ("GDLs"). The ion exchange membrane 56 may be at least partially disposed between the OER catalyst 58 and the HER catalyst 60. The gaskets 52 may be at least partially disposed between the flow field plates 50. The flow field plates 50 may be at least partially disposed between the separators and / or bipolar plates 36. The separators and / or bipolar plates 36 may include end plates 49 and current collectors 48. The single cell ion exchange electrolyzer 42 may include an anode cell 44. The anode cell 44 can include a separator and / or bipolar plate 36, a flow field plate 50, a gasket 52, and an OER catalyst 58. The single cell ion exchange electrolyzer 42 can include a cathode cell 46. The cathode cell 46 can include a separator and / or bipolar plate 36, a flow field plate 50, a gasket 52, and an HER catalyst 60. Figure 4 shows one embodiment of a separator and / or bipolar plate having a serpentine channel pattern 62 that can be a component of the single cell ion exchange electrolyzer 42.

[0042] 5A and 5B show an electrolysis cell 64 with an applied magnetic field and graphs showing current flow and magnetic field in the electrolysis cell 64 with an applied magnetic field. The cell assembly 65 can be positioned at least partially between a magnetic field south end 66 and a magnetic field north end 68. The cell assembly 65 can include separators and / or bipolar plates 36, electrodes 38, and membranes 40. If desired, the electrodes 38 can be later replaced with a porous transport body and / or the membranes 40 can be replaced with an MEA including a catalyst, a GDL, and electrodes 38. A magnetic field 69 can be applied to the separators and / or bipolar plates 36 and / or electrodes 38. The magnetic field can be applied parallel to the magnetic field south end 66 and the magnetic field north end 68, and a current can be applied perpendicular to the magnetic field. The current can flow across and / or through at least one of the components of the cell assembly 65.

[0043] 6A and 6B show electrode arrangements photoelectrochemical system 70 and photoelectrochemical system 78. Photoelectrochemical system 70 includes a photocathode 74 disposed at least partially between a photoanode 72 and a solar panel 76. Photoelectrochemical system 78 includes a photoanode 72 disposed at least partially between a photocathode 74 and a solar panel 76. The solar panel 76 can convert solar radiation into electrical power and provide a voltage to the photoanode 72 and / or across the photocathode 74. If desired, the photoanode 72 and / or photocathode 74 may generate electron current by directly receiving solar radiation.

[0044] FIG. 7 shows an embodiment of the electrode fabrication by sputtering or electroplating. In the sputtering fabrication method 80, the substrate may be pretreated by a cleaning step 82. The cleaning step 82 may include degreasing and / or deoxidization. The substrate may then be electrochemically activated 84 by applying an electric current. The activated substrate may be dried 86, followed by sputtering 88 of a compound comprising a primary material and a support material. The support material may include a roughened material. The primary material and the support material may be subjected to a leaching treatment 90. If necessary, the scarified compound may be doped 92 to introduce a dopant into the primary material. The substrate with the roughened compound may be subjected to a heat treatment 94.

[0045] In the electroplating process 96, the substrate may be pretreated by a cleaning step 82. The cleaning step 82 may include degreasing and / or deoxidization. The substrate may then be electrochemically activated 84 by applying an electric current. The activated substrate may be electroplated 98 with a compound including a primary material and a support material. The support material may include a roughened material. The primary material and the support material may be subjected to a leaching process 90. If necessary, the scarified compound may be doped 92 to introduce a dopant into the primary material. The substrate with the roughened compound may be subjected to a heat treatment 94.

[0046] FIG. 8 illustrates an electrode fabrication method 100. The electrode substrate may be subjected to a chemical and electrochemical pretreatment 102 followed by a first material deposition 104. The substrate may then be subjected to a first heat treatment 106 followed by a first reagent wash 108 and a second reagent wash 110. The water may include distilled water and / or purified water. The substrate may then be subjected to an acid wash 122 followed by a third reagent wash 114. The substrate may then be subjected to an electrochemical activation 116 followed by a fourth reagent wash 118. The substrate may then be dried 120 and a second material deposition 122 may be performed. The substrate with the deposited material may then be subjected to a selective etching and / or leaching treatment 124 followed by a fifth reagent wash 126 and a second heat treatment 128. The reagents in any of the cleaning steps may include isopropyl alcohol, distilled water, purified water, acetone, ethanol, or combinations thereof.

[0047] Figure 9 shows a series of graphs comparing the initial performance and stability data of MEAs of the present invention and commercial MEAs. The results demonstrate that MEAs of the present invention can achieve the same current density at a lower applied voltage compared to commercial MEAs. The results also demonstrate that MEAs of the present invention have improved long-term stability compared to commercial MEAs.

[0048] Figure 10 shows a series of graphs illustrating the initial performance and current density of the novel electrodes of the invention compared to commercially available electrodes. The graphs compare the initial performance and stability data of a commercially available MEA incorporating a cation exchange membrane with the MEA of the invention incorporating a cation exchange membrane. The cation exchange membrane is disposed at least partially between the anode and cathode compartments of the MEA of the invention and the commercial MEA.

[0049] FIG. 11 illustrates the effect of selective etching of roughening and / or leaching of material from the cathode and anode. The graph shows the performance of a cathode that was not selectively etched or leached and a cathode that was selectively etched or leached. The cathode that was selectively etched or leached retained more energy for a given voltage than the cathode that was not selectively etched or leached. The graph also shows the performance of an anode that was not selectively etched or leached and anode that was selectively etched or leached. The anode that was selectively etched or leached retained more energy for a given voltage than the anode that was not selectively etched or leached.

[0050] The effect of heat treatment of the cathode and anode is shown in Figure 12. The graph shows the performance of the cathode and anode with and without heat treatment. Heat treatment improved the performance of the cathode and anode.

[0051] 13 shows a microporous structure formed by roughening and / or leaching material from the cathode and / or anode. The image series 130 shows pores 134 interspersed among the roughened and / or leached material 132. The image series 130 also shows a catalytic material 138 bonded to a substrate 136.

[0052] Figure 14 shows the results of the analysis using 1M KOH and 0.2M N 2 H 4 Current density in 10mA cm -2 This figure shows the long-term stability of a two-electrode hydrazine electrolyzer at 200 K for 100 hours. The voltage was stable over 100 hours. The voltage remained at approximately 0.45 V during operation of the hydrazine electrolyzer system.

[0053] The electrolyzer system may include at least one electrolyzer stack. The electrolyzer stack may include at least one electrolysis cell. The electrolysis cell may include an anode cell and / or a cathode cell. The anode cell and / or the cathode cell may include a bipolar plate, a flow field plate, a gasket, an electrode, a catalyst, or a combination thereof. The membrane may be disposed between the anode cell and the cathode cell. The bipolar plate may include an end plate, a current collector, a flow channel, or a combination thereof, and may facilitate the conversion of the dissolved gas into a gas in the solution. The flow field plate may provide a flow field.

[0054] The electrolyzer system may include a membrane. The membrane may include a proton-exchange membrane ("PEM"), anion-exchange membrane ("AEM"), alkaline electrolyser ("AE") stack, or a combination thereof. The PEM and / or AEM may include PGM. The PEM and AEM may be ion-exchange membranes. The electrolyzer system may further include a cation-exchange membrane, including but not limited to Nafion 115, Nafion 117, Nafion 212, perfluorosulfonic acid membrane, polytetrafluoroethylene membrane, chlor-alkali membrane, carboxylic acid membrane, or a combination thereof. The electrolyzer may achieve high cell current density using electrodes including metal or mixed metal-metal oxide microstructures and / or nanostructures. The electrolyzer may include a cathode catalyst and / or an anode catalyst. The cathode catalyst and / or an anode catalyst may include PGM. The magnetic field can be applied externally to the electrolyzer system, including, but not limited to, the PEM, the AEM, the AE stack, the electrodes, the catalyst, or a combination thereof. The electrolyzer system can be a hydrogen electrolyzer system. The membrane has a magnetic field of at least about 0.2 mg cm -2 , about 0.2 mg cm -2 ~Approx. 3mg cm -2 , about 0.4 mg cm -2 ~Approx. 2.5mg cm -2, about 0.6 mg cm -2 ~Approx. 2.0mg cm -2 , about 0.8 mg cm -2 ~Approx. 1.5mg cm -2 , about 1.0 mg cm -2 ~Approx. 1.2mg cm -2 , or approximately 3 mg cm -2 may have:

[0055] The MEA may include an AEM. The MEA may include a binder. The binder may include an anionic binder, a cationic binder, or an ionomeric binder, or a combination thereof. The binder may be disposed at least partially between the anode and the AEM. The binder may also be disposed at least partially between the cathode and the AEM. The AEM may include an anion exchange membrane and / or a cation exchange membrane. The binder may enhance the ionic conductivity between the AEM and the anode and / or cathode by at least about 10%, about 10% to about 40%, about 15% to about 35%, about 20% to about 30%, or about 40%. The binder may include an ionomer and may include anionic or cationic. The binder may be disposed between the AEM and the corresponding anode or cathode in the following order: ● anode, first (anionic) binder, AEM, second (anionic) binder, cathode; ● anode, first (cationic) binder, AEM, second (cationic) binder, cathode; an anode, a first (anionic) binder, an AEM, a second (cationic) binder, a cathode; or Anode, first (cationic) binder, AEM, second (anionic) binder, cathode The at least partially disposed in one of

[0056] The membrane of the MEA may include a PEM. The PEM has a current density of about 4 A cm -2 Less than 0.5A cm -2 ~Approx. 4A cm -2 , about 1A cm -2 ~Approx. 3.5A cm -2 , about 1.5A cm-2 ~Approx. 3A cm -2 , about 2A cm -2 ~Approx. 2.5A cm -2 , or about 4A cm -2 The cationic binder may be at least partially disposed between the anode and the PEM and / or between the cathode and the PEM. The cationic binder may include an ionomer and may be prepared from an ionomer solution of at least about 5 wt%, about 5 wt% to about 20 wt%, about 10 wt% to about 15 wt%, or about 20 wt%. In conventional PEM electrolyzer technology, the anode catalyst and the cathode catalyst include PGMs. Platinum is primarily used to make the cathode, and iridium and ruthenium are used to make the anode. The amount of platinum group material used by conventional PEM electrolyzer technology is typically 1-3 mg / cm. 2 The electrolytic cell systems of the present invention containing PEM can have a PEM content of at least about 0.01 mg / cm without loss of performance. 2 , about 0.01mg / cm 2 ~about 0.1mg / cm 2 , about 0.02 mg / cm 2 ~about 0.09mg / cm 2 , about 0.03mg / cm 2 ~ approx. 0.08 mg / cm 2 , about 0.04 mg / cm 2 ~about 0.07mg / cm 2 , about 0.05mg / cm 2 ~about 0.06mg / cm 2 , about 0.1mg / cm 2 The PEM may also include a cation membrane and / or a cation exchange membrane.

[0057] The electrolyzer system may include a photoelectrochemical ("PEC") system used for water splitting. The PEC system may include a transparent / semitransparent photo-anode (PA), a transparent / semitransparent photo-cathode (PC), a solar cell (SC), or a combination thereof. The PEC system may enable the production of green hydrogen from sunlight and water with high solar-to-hydrogen conversion efficiency, i.e., the yield of hydrogen gas is high compared to the amount of hydrogen produced by an electrolyzer and solar panel without the PEC system. The PEC system may include non-III-V compound materials, such as conductive metal oxides and perovskite materials.

[0058] The electrolyzer system may be equipped with solar panels as a power source. Solar panels can be integrated into the PEC system to produce green hydrogen directly from sunlight and water, improving the solar to hydrogen (STH) efficiency.

[0059] The photoanode is BiVO 4 , TiO 2 , WO 3 , SrTiO 3 , Fe 2 O 3 The photoanode may include n-type semiconductors and / or perovskite materials, including but not limited to, ZnO, ZnO, or combinations thereof. The n-type semiconductors and / or perovskite materials used to form heterostructures with bandgaps that may be transparent. Other compatible materials may also be co-deposited during deposition of the anode materials to form high performance n-type semiconductors. ZnO and Ti may be co-deposited, or ZnO, Ti and W may be co-deposited to form high performance mixed oxides. The photoanode may also be coated with nanoparticles of an anode catalyst, including but not limited to, PGM-based or Ni-based alloys, to improve the overall performance of the photoanode.

[0060] The photocathode may include p-type semiconductors and / or perovskite materials, including but not limited to copper-based oxides, alloys of p-type metal oxides, or combinations thereof. The p-type semiconductors and / or perovskite materials may form heterostructures with bandgaps that may be transparent. The photocathode may be coated with nanoparticles of a cathode catalyst, including but not limited to PGM-based or Ni-based alloys, to improve the overall performance of the photocathode.

[0061] The photoelectrode, e.g., photoanode and / or photocathode, must have a current of 14 mA cm with a fill factor of >50%. -2 Photoelectrodes can be fabricated to achieve photocurrent densities in excess of 100 nm. The materials in the photoelectrode can be optimized to achieve a crystalline structure. The crystalline structure may require the formation of nanocrystals on the photoelectrode. The nanocrystals can be formed by tailoring the deposition of the materials onto the electrode, for example, by controlling the deposition time, deposition temperature, deposition pressure, by controlling the reactive gas, or a combination thereof. Also, the interface between the nanocrystals and the electrode surface can be optimized to incorporate the nanocrystals into the photoelectrode. The interface can be optimized by controlling the deposition parameters of each material, for example, by controlling the deposition time, deposition temperature, deposition pressure, reactive gas, deposition power, gas flow rate, or a combination thereof. The interface design can prevent changes in the surface morphology and shape of the nanocrystals.

[0062] The photoanode and photocathode may then be integrated with each other using sequential deposition. The integrated photoelectrode may then be directly integrated with a solar cell or solar panel using physical and / or chemical deposition. The integration of the photoelectrode with the solar cell or solar panel can be done by controlling the light absorption of each photoelectrode or solar component so as not to interfere with the performance of the remaining photoelectrode or solar component. The light absorption can be controlled by adjusting the crystal quality and thickness of the material by adjusting the deposition parameters.

[0063] The STH efficiency of a PEC system may depend on the short circuit photocurrent density, the faradaic efficiency of hydrogen evolution, and the incident light power density. All these parameters should be measured under standard solar illumination conditions (AM 1.5G solar spectrum). The STH efficiency can be measured according to Equation 1:

number

[0064] The STH efficiency is calculated by the thermodynamic potential (V redox ) multiplied by the electrolysis current (IWE) and the Faraday efficiency for hydrogen evolution (ηF), then divided by the input light power (Pin).

[0065] PEC systems can use non-III-V materials, which can affect photocurrent density and hydrogen generation while achieving STH efficiencies up to 30%, which is approximately three times higher than the STH efficiencies achieved with conventional PEC technology.

[0066] The electrolyzer system may include at least one electrolytic cell at least partially disposed between a pair of electromagnetic plates. The pair of electromagnetic plates may be disposed electromagnetically perpendicular to the flow of current in the stack of electrolytic cells. The electromagnetic plates may generate a quasi-uniform magnetic field. The electromagnetic plates may accelerate the collection of hydrogen gas. The acceleration of the hydrogen gas may be achieved by the cooperative effect of the quasi-uniform magnetic field and the flow of current of charge carriers with the electrolyzer stack. The charge carriers may include protons.

[0067] Electrolyzer systems can produce hydrogen from nitrogen compounds in solution (nitrogen-assisted hydrogen production). Nitrogen-assisted hydrogen production is achieved by using a membrane electrolyser (either PEM or AEM), N 2 Gas and H 2This may occur in an alkaline electrolyzer that includes a membrane for separating the gases, a membrane-free electrolyzer, or a combination thereof. Nitrogen-assisted hydrogen production may require contacting a nitrogen compound with the electrolyzer. Nitrogen and hydrogen may be produced according to Equation 2 or Equation 5, which are derived from the anodic half-reactions of Equation 3 and Equation 6, and the cathodic half-reactions of Equation 4 and Equation 7. JPEG2024535633000003.jpg47153

[0068] Nitrogen compounds may include hydrazine, urea, and other reagents that can decompose to nitrogen when dissolved in the electrolyte. Nitrogen-assisted hydrogen generation can generate nitrogen on the anode side (e.g., the anode) instead of oxygen generation. Nitrogen generation can reduce the overall cell voltage and power required to operate the electrolyzer system. The surface properties of the electrolyzer system electrodes can be tailored to vary the electrochemical potential of the electrodes. Electrolyzer systems that decompose nitrogen compounds to generate nitrogen and oxygen can operate with an applied voltage of at least about 10 mV to about 1.5 V, about 50 mV to about 1.0 V, about 100 mV to about 0.8 V, about 0.2 V to about 0.6 V, or about 1.5 V. Electrolyzer systems using nitrogen-assisted hydrogen generation can operate without an applied voltage and / or generate electricity as a by-product.

[0069] An electrolyzer system using nitrogen assisted hydrogen generation is an electrolyte bath that contains hydrazine, urea, any other reagent that can be decomposed to nitrogen when dissolved in the electrolyte, or a combination thereof; distilled water; KOH, NaOH, K 2 CO 3 or combinations thereof; 2 SO 4 , H 2 CO 3or a combination thereof. The KOH can be at a concentration of at least about 1.0M, about 1.0M to about 5.0M, about 1.5M to about 4.5M, about 2.0M to about 4.0M, about 2.5M to about 3.5M, or about 5.0M. Hydrazine, urea, any other reagent that can be decomposed to nitrogen when dissolved in the electrolyte, or combinations thereof, can be at a concentration of about 0.01M or more, about 0.01M to about 3.0M, about 0.5M to about 2.5M, about 1.0M to about 2.0M, or about 3.0M. 2 H 4 or CO(NH 2 ) 2 The bath can be operated at a temperature of about 20° C. or higher, about 20° C. to about 80° C., about 25° C. to about 75° C., about 30° C. to about 70° C., about 35° C. to about 65° C., about 40° C. to about 60° C., about 45° C. to about 55° C., or about 80° C. The oxygen evolution reaction is prevented by the dominance of the nitrogen evolution reaction by controlling the concentration of the nitrogen compounds via a closed circulating bath and an automatic dosing system. 2 and O 2 The risk of explosion caused by mixtures with is eliminated.

[0070] The electrolyzer system may include a power source. The power source may generate an AC, DC, pulsed current, or a combination thereof. The power source may generate electrical energy from a renewable energy source, including, but not limited to, solar radiation, thermal energy, tidal current, wind, bioenergy, or a combination thereof. The power source may transmit power, e.g., electrical current, to the electrolyzer cells of the electrolyzer system. The electrical energy may be transmitted from the power source to the electrolyzer system by at least one electrical wire.

[0071] The electrolytic cell system may be operated at a temperature of about 20° C. or higher, from about 20° C. to about 80° C., from about 30° C. to about 70° C., from about 40° C. to about 60° C., or about 80° C. The operating temperature may be preferably about 60° C.

[0072] The electrolytic cell system may include an electrolyte. The electrolyte may include an alkaline electrolyte. The alkaline electrolyte may include an alkali metal, including, but not limited to, lithium ("Li"), sodium ("Na"), potassium ("K"), rubidium ("Rb"), cesium ("Cs"), francium ("Fr"), or combinations thereof. The electrolyte may include, but is not limited to, KOH, K 2 CO 3 , NaOH, or a combination thereof. The electrolyte can be at a concentration of about 0.1 M or greater, about 0.1 M to about 3 M, about 0.5 M to about 2.5 M, about 1.0 M to about 2.0 M, or about 3.0 M.

[0073] The MEA may be directly bonded to the pair of electrodes and / or may be at least partially disposed between the pair of electrodes. The pair of electrodes may include an anode and a cathode. The anode and cathode may include a GDL and a catalyst in communication with the GDL. The catalyst may be attached to the GDL by physical or chemical deposition. The GDL may include a porous layer. Optionally, the anode and / or cathode may be a GDL with a catalyst coated on the surface of the anode and / or cathode. The GDL may include conductive fibers, paper, foam, mesh, felt, or combinations thereof. The GDL may have a thickness of about 0.1 mm or more, about 0.1 mm to about 2 mm, about 0.2 mm to about 1.6 mm, about 0.4 mm to about 1.2 mm, about 0.6 mm to about 0.8 mm, or about 2 mm. The GDL can have a specific or variable porosity of about 10% or more, about 10% to about 99%, about 20% to about 97%, about 30% to about 95%, about 40% to about 90%, about 50% to about 80%, about 60% to about 70%, or about 99%.

[0074] The electrodes (e.g., cathode and / or anode), catalysts can be selected from HER and / or OER volcanographs and can depend on the desired current density of the electrolyzer system. HER catalysts can include, but are not limited to, Mo, Nb, W, Co, Ni, Re, Rh, Pd, Pt, Ir, Au, Ag, Fe, Ti, Ta, Tl, Cu, Bi, Cd, Ga, or combinations thereof. OER catalysts can include, but are not limited to, Cr, Ru, Mn, Fe, Ir, Co, Rh, Ni, Pt, Cu, Pt, Ag, Zn, Au, NbOx, ReOx, VOx, CrOx, SnObx, MoOx, MnOx, PtOx, IrOx, RuOx, TiOx, NiOx, PbObx, CoOx, or combinations thereof. The HER and / or OER are determined by determining whether the electrolyzer system, electrolysis cell, and / or electrodes are capable of providing at least about 0.5 A cm at a cell voltage of 1.8 V. -2 More than approximately 0.5A cm -2 ~Approx. 2A cm -2 , about 0.75A cm -2 ~Approx. 1.75A cm -2 , about 1A cm -2 ~Approx. 1.5A cm -2 , or about 2A cm -2 The cathode and anode catalysts may comprise a non-PGM selected from one of the following: ●(Ni 0.7±0.1 Fe 0.3±0.1 ) α X β Y γ , where α+β+γ=100% (α is ≧50%, and β and γ make up the remaining 50%, each in the range of 0-50%), and X and Y are selected from one of Cr, Co, Mo, W, O, S, P, and N. ●(Al 0.5±0.1 )((Ni 0.7±0.1 Fe 0.3±0.1 ) α X β Y γ ) 0.5±0.1, where α+β+γ=100% (α is ≧50%, and β and γ make up the remaining 50%, each in the range of 0-50%), X and Y are selected from one of Cr, Co, Mo, W, O, S, P, and N, and the catalyst is activated by leaching aluminum to form a pore-like structure. ●(Al 0.5±0.1 )(Ni 0.7±0.1 Mo 0.3±0.1 ) 0.5±0.1 , where the catalyst is activated by leaching aluminum to form a pore-like structure, and the current density is 2 A × cm at a cell voltage of 1.8 V. -2 Greater than.

[0075] The cathode catalyst is: ●(Al 0.5±0.1 )(Mo 0.7±0.1 Pt 0.3±0.1 ) 0.5±0.1 , and ●Al 0.7±0.1 Pt 0.3±0.1 The PGM may be selected from:

[0076] The anode catalyst may comprise a PGM activated by leaching aluminum to form a pore-like structure selected from the following: ●(Al 0.5±0.1 )(Ir x Ru y ) 0.5±0.1 , ●(Ni 0.7±0.1 Fe 0.3±0.1 ) α X β Y γ an inner layer of α+β+γ=100% (α is ≧50%, β and γ make up the remaining 50%, each in the range of 0-50%), and X and Y are selected from one of Cr, Co, Mo, W, O, S, P, N, and Al 0.7±0.1 (IrOx) 0.3±0.1 The outer layer of ●(Ni 0.7±0.1 Fe 0.3±0.1 ) α X β Y γwherein α+β+γ=100% (α is ≧50%, β and γ make up the remaining 50%, each in the range of 0-50%), and X and Y are selected from one of Cr, Co, Mo, W, O, S, P, N, and (Al 0.5±0.1 )(Ir x Ru y ) 0.5±0.1 The outer layer of ●(Ni 0.7±0.1 Fe 0.3±0.1 ) α Al β (where α+β+γ=100% (α is ≧50%, and β and γ make up the remaining 50%, each in the range of 0 to 50).

[0077] The bipolar plates may include gas and / or liquid flow paths. The gas and / or liquid flow paths may include channels. The channels may include, but are not limited to, serpentine, column pin, or parallel or straight channel patterns, or combinations thereof. The bipolar plates may include current collectors, electrolyte pressure and flow controllers, electrical resistance regulators, or combinations thereof. The surface design of the channel patterns of the bipolar plates and the materials deposited on these plates may affect the electrolyte pressure, electrolyte flow, and / or electrical resistance of the bipolar plates. The channel patterns of the bipolar plates may have a defined depth, width, and curvature.

[0078] The channel pattern of the bipolar plate can facilitate liquid and / or gas management within the electrolysis. Optimizing the bipolar plate can prevent gas from being trapped within the electrolytic cell system and can result in improved electrolyte flow within and gas release from the electrolytic cell system. Optimization of the bipolar plate can be done by modifying the pattern of gas and / or liquid flow paths to prevent gas from being trapped within the bipolar plate and / or the electrolytic cell system, and by coating the bipolar plate with conductive and / or corrosion-resistant materials to avoid oxidation and increase electrical conductivity. The bipolar plate can include nickel, stainless steel, titanium, carbon-based products, and aluminum, plastic, acrylic, foam, or combinations thereof. The conductive corrosion-resistant material can include alloys including, but not limited to, gold, silver, copper, aluminum, nickel, iron, molybdenum, chromium, niobium, ruthenium, rhodium, palladium, osmium, iridium, platinum, zinc, bronze, brass, or combinations thereof.

[0079] The electrolytic cell system may include electrodes fabricated by sputtering or electroplating methods. The electrodes may be fabricated by first pretreating a substrate. The substrate may include, but is not limited to, nickel, chromium iron, molybdenum, copper, titanium, steel, stainless steel, nickel-chromium alloy, nickel-iron alloy, nickel-molybdenum alloy, nickel-copper alloy, titanium alloy, felt, paper, foam, or combinations thereof. The substrate may be cleaned and / or degreased to remove oil, grease, and / or native oxides from the substrate. The substrate may be cleaned and / or degreased by ultrasonic cleaning (resistivity greater than 18 Ω×cm) and / or contact with NaOH, acetone, ethanol, methanol, isopropyl alcohol, distilled water, or combinations thereof. The substrate may be cleaned and / or degreased at least once for about 5 minutes or more, about 5 minutes to about 30 minutes, about 10 minutes to about 25 minutes, about 15 minutes to about 20 minutes, or about 30 minutes. Native oxides may be removed from the surface of the substrate by contacting the substrate with an acid. The substrate may be immersed in an acidic solution, which may include, but is not limited to, hydrochloric acid, hydrofluoric acid, sulfuric acid, or combinations thereof.

[0080] Optionally, the substrate may be contacted with an etching agent capable of at least partially removing the native oxide from the substrate. The acid may be at a concentration by weight (w / w) in solution of about 5% or more, about 5% to about 50%, about 10% to about 45%, about 15% to about 40%, about 20% to about 35%, about 25% to about 30%. The acid may be at a temperature of about 50°C or more, about 50°C to about 80°C, about 55°C to about 75°C, about 60°C to about 70°C, or about 80°C.

[0081] The substrate can be electrochemically activated by applying a current to the substrate. The applied current density is about 40 mA / cm 2 Above, approximately 40mA / cm 2 ~Approx. 1000mA / cm 2 , about 80mA / cm 2 ~about 900mA / cm 2 , about 100mA / cm 2~about 800mA / cm 2 , about 200mA / cm 2 ~about 700mA / cm 2 , about 300mA / cm 2 ~about 600mA / cm 2 , about 400mA / cm 2 ~about 500mA / cm 2 , or about 1000mA / cm 2 The substrate may be activated by an HCl soak followed by washing and / or rinsing with acetone and / or deionized water.

[0082] The material can be applied to the substrate using sputtering or electrodeposition. If the material is applied using sputtering, the substrate may be dried. Drying may include nitrogen drying. If necessary, drying may be performed in a vacuum oven at a temperature range of about 60° C. or higher, about 60° C. to about 250° C., about 80° C. to about 230° C., about 100° C. to about 210° C., about 120° C. to about 190° C., about 130° C. to about 170° C., or at about 250° C ... The substrate may be completely dried. If the material is applied using electroplating, the substrate may be rinsed with a solvent. The solvent may include distilled water and / or purified water.

[0083] The material may be deposited on the surface of the electrode substrate. The material may include a compound material. The compound material may be deposited on the surface of the substrate by physical deposition, including but not limited to sputtering, e-beam evaporation, or a combination thereof, or may be deposited on the surface of the substrate by chemical deposition, including but not limited to electroplating, electrochemical deposition, or a combination thereof. The compound material may include a primary material and a support material. The primary material may include a catalyst. The catalyst may include, but is not limited to, Ir, Pt, Ru, Re, Pd, Ni, Fe, Mo, Cr, W, Ti, Co, alloys of Ir, Pt, Ru, Re, Pd, Ni, Fe, Mo, Cr, W, Ti, Co, or combinations thereof. The compound material may include, but is not limited to, NiPt, NiIr, NiRu, PtIr, PtRu, IrRu, IrW, IrTi, IrPd, or combinations thereof. The support material may include a roughening material and a dopant.

[0084] The roughening material may include, but is not limited to, Li, Ca, Na, Al, Mg, Zn, or combinations thereof. The roughening material may have a lower electrochemical potential compared to the main catalyst. The main material and the support material may be deposited simultaneously on the substrate. The amount of the main material and the support material deposited on the substrate may be 25% or more of the weight of the substrate. The roughening material may be subsequently leached from the compound material by selective etching. An etchant or etching method may be used to selectively etch and / or leach the roughening material. Etching and / or negligible etching of the main material may occur during the leaching and / or selective etching process. The main material and the roughening material may be deposited simultaneously using either physical and / or chemical deposition methods.

[0085] The simultaneous deposition of the primary material and the roughening material can be done by using a compound target and / or a compound target precursor of the material, or a multi-target and / or a multi-target precursor of the material, when using a physical deposition method. The compound and / or the multi-target can depend on the physical deposition method. The precursor can be an atom in the compound and / or the multi-target, e.g., Pt, Ni, etc. By selecting the appropriate target or precursor, the compound material can be deposited, i.e., bonded, onto the substrate. For example, when depositing the compound material by a sputtering method, a sputtering target can be used. The sputtering target can be a single material, including but not limited to Pt, Ni, or a combination thereof, and / or a combination of materials, including but not limited to NiPt, NiMo, NiPtIr, or a combination thereof. The target or compound target can be specific to the method. For example, when depositing the compound material on the substrate using electron beam evaporation, a precursor can be used instead of the compound or the multi-target. A mixed salt compound or a salt of the compound material can be used to apply the compound material to the substrate using a chemical deposition method. The salt can be NiCl 2 6H 2 O, FeCl 2 4H 2 O, CoCl 2 6H 2 O, (NH 4 ) 2 MoO 4 , ZnCl 2 , T / H 2 PtCl 6 , CoCl 2 6H 2 O, Ti / IrCl 4 H 2 O, ZnCl 2 , or combinations thereof. When applying a compound material using electrochemical deposition, a pulsed current wave can be used. The pulse wave can be t onHowever, the pulse wave may be at least about 50 μs (microseconds), about 50 μs to about 5000 μs, about 100 μs to about 4500 μs, about 200 μs to about 4000 μs, about 300 μs to about 3500 μs, about 400 μs to about 3000 μs, about 500 μs to about 2500 μs, about 600 μs to about 2000 μs, about 700 μs to about 1500 μs, about 800 μs to about 1000 μs, or about 5000 μs. off may be in the range of at least about 10 μs, about 10 μs to about 1000 μs, about 100 μs to about 900 μs, about 200 μs to about 800 μs, about 300 μs to about 700 μs, about 400 μs to about 600 μs, or about 1000 μs. Each compound material can be deposited separately and simultaneously to achieve the target composition, i.e., simultaneous codeposition of the main material and the support material onto the substrate can be achieved. Co-deposition allows the alloy and electrode to be formed using up to 10 times less PGM material while exhibiting high catalytic activity compared to conventional electrodes. The catalytic activity of the electrode is related to the surface of the active area. The roughened material is leached and / or selectively etched to form a micro- and / or nano-porous structure in the electrode. The leached and / or selectively etched roughened material leaves pores in the compound material. The formation of the micro- and / or nano-porous structure increases the exposed surface area and / or active area of ​​the catalytic material. The increased surface area increases the catalytic activity of the electrode while reducing the amount of catalyst material required to fabricate the electrode. The active area can be increased by at least about 30%, about 30% to about 150%, about 40% to about 125%, about 50% to about 100%, about 60% to about 75%, or about 150%. The surface area of ​​the catalyst can be increased by at least about 10%, about 10% to about 75%, about 20% to about 70%, about 30% to about 60%, about 40% to about 50%, or about 75%.

[0086] By leaching and / or selectively etching the roughened material, micropores and / or nanopores can be formed in the compound material. The porous compound material can form the microporous and / or nanoporous structure of the electrode. The pore size in the nanoporous structure can be on the order of the width of the leached and / or selectively etched atoms, so that the size of the pore size is sufficient to accommodate the leached and / or selectively etched atoms. For example, in a compound material containing NiPt, when Ni atoms are leached and / or selectively etched from the NiPt compound, a nanoporous structure containing nanopores is formed. The nanopores have a diameter sufficient to accommodate the Ni atoms.

[0087] The support material may include doping agents, including but not limited to nitrogen, phosphorus, sulfur, boron, molybdenum, iron, chromium, cobalt, copper, or combinations thereof. The support material may include doping compounds, including but not limited to oxynitrides, nitrogen and sulfur compounds, nitrogen and phosphorus compounds, nitrogen and boron compounds, nitrogen and molybdenum compounds, nitrogen and iron compounds, or combinations thereof. Doping may be introduced as trace impurities into the main compound to change the surface properties, including but not limited to the electrical properties or electrochemical potential of the electrode. The doping agents may be present in trace amounts, i.e., less than 5%, in the main material. The doping agents may have different atomic sizes and configurations compared to the main compound, which is why they are called impurities. Doping may occur during or after deposition of the compound material. The doped material may have a lower cell potential compared to the theoretical minimum, which may be 1.23 V to less than 0, depending on the doping material and its concentration. By lowering the cell potential, the power applied to the cell may be reduced, thereby improving the overall efficiency of the electrolytic cell. The dopant can improve the efficiency of the electrolytic cell system by at least about 10%, between about 10% and about 80%, between about 20% and about 70%, between about 30% and about 60%, between about 40% and about 50%, or about 80%.

[0088] By adding doping agents to the electrode, the electrode surface properties can be tailored to have a minimum required potential and / or maximum efficiency. Doping agents can be added to the electrode by codeposition in the sputtered compound material, by using reactive gases during sputtering, by electrochemical and / or thermochemical addition after leaching and / or selective etching, or by a combination thereof. In the co-deposition method, the doping agent can be simultaneously deposited on the electrode with other components of the compound material. The doping agent can be less than 10% of the compound material. In the reactive gas method, the ratio of nitrogen gas to argon gas can be less than about 30% to diffuse the doping agent, e.g., nitrogen, into the electrode simultaneously with the deposition of the main material. In electrochemical doping, the doping agent, which can include but is not limited to N, P, S, and / or B, can be dissolved / dispersed in the electrolyte solution. By applying an electric potential to the electrolyte solution, the doping agent can be incorporated into the electrode and / or compound material. The potential can be at least about 50 mV, about 50 mV to about 1500 mV, about 100 mV to about 1300 mV, about 200 mV to about 1100 mV, about 300 mV to about 900 mV, about 500 mV to about 700 mV, or about 1500 mV. In thermochemical doping, the compound material and the dopant can be placed in an inert gas filled furnace, for example under an argon atmosphere. The dopant can be fixed, diffused and / or added to the compound material by increasing the temperature. To dope the compound material with the dopant, the temperature can be increased to about 250°C or higher, about 250°C to 900°C, about 300°C to 800°C, about 400°C to 700°C, about 500°C to 600°C, or about 900°C. For all methods, the doped electrodes can be treated with a reagent including, but not limited to, potassium hydroxide (KOH), sodium potassium tartrate tetrahydrate, or a combination thereof, followed by deionized water washing, nitrogen drying, oven drying, or a combination thereof to form a microporous and / or nanoporous structure. Additionally, for all methods, the dopant can be embedded, doped, and / or added to the support material of the compound material.

[0089] The roughened material may be leached using various types of etching methods, including but not limited to physical etching (including but not limited to reactive ion etching (RIE) and inductively coupled plasma etching) or chemical / electrochemical etching. Etching requires contacting the roughened material with a substance to remove it. One or more gases may be used as the etchant in physical etching. Reagents may be used in chemical / electrochemical etching. Electrodes may be etched by immersion in a bath containing a chemical / electrochemical etchant. The bath composition, operating temperature, time, and applied current may vary depending on the material selected for etching.

[0090] The bath for chemical / electrochemical etching is KOH, NaOH, HCl, H 2 SO 4 The bath may include a basic or acidic solution, including but not limited to, a salt, an antiscalant, an etch accelerator, or a combination thereof. The bath may also include additives, including but not limited to, a buffering agent, hydrazine, an antiscalant, an etch accelerator, or a combination thereof. The buffering agent may include but is not limited to, boric acid, a borate salt, or a combination thereof, and may be used to maintain the pH of the bath. Hydrazine may be used to prevent oxidation in baths with low pH values. Antiscaling agents, including but not limited to, polyphosphates, may prevent salt precipitation on the electrodes during etching. Etching accelerators, including but not limited to, sodium potassium tartrate tetrahydrate, may promote etching in an alkaline environment. The bath may be operated at a temperature of about 25° C. or higher, about 25° C. to about 85° C., about 30° C. to about 80° C., about 35° C. to about 75° C., about 40° C. to about 70° C., about 45° C. to about 65° C., about 50° C. to about 60° C., or about 85° C. An electric current may be applied to the bath. The current may include a direct current, an alternating current, a pulsed current, or a combination thereof. The applied direct current may be at least about 25 mA / cm 2 , about 25mA / cm 2 ~Approx. 1000mA / cm2 , about 50mA / cm 2 ~about 900mA / cm 2 , about 100mA / cm 2 ~about 800mA / cm 2 , about 200mA / cm 2 ~about 700mA / cm 2 , about 300mA / cm 2 ~about 600mA / cm 2 , about 400mA / cm 2 ~about 500mA / cm 2 , or about 1000mA / cm 2 It could be.

[0091] The electrolytic cell system may include at least one electrode. The electrode may include an anode and / or a cathode. The electrode may be heat treated to improve performance. The electrode may be subjected to a vacuum heat treatment. The vacuum heat treatment may be performed at a temperature of about 300° C. or higher, about 300° C. to about 1000° C., about 400° C. to about 900° C., about 500° C. to about 800° C., about 600° C. to about 700° C., or about 1000° C. The vacuum heat treatment may be performed for at least about 30 minutes, about 30 minutes to about 4 hours, about 1 hour to about 3.5 hours, about 1.5 hours to about 3 hours, about 2 hours to about 2.5 hours, or about 4 hours. The heat treatment may include increasing the temperature of the electrode, maintaining the temperature of the electrode, and decreasing the temperature of the electrode. The electrode temperature can be increased and decreased at a rate of at least about 5° C. / min, about 5° C. / min to about 20° C. / min, about 10° C. / min to about 15° C. / min, or about 20° C. / min.

[0092] The actual cell voltage of the electrolyzer system can be less than about 100 mV, compared to the theoretical minimum voltage of 1230 mV for water splitting at ambient temperature. The microporous and / or nanoporous structure of the catalytic composition of the electrodes can reduce the cell voltage for water splitting to 0 mV, i.e., the electrolyzer system becomes an autonomous electrolyzer and can operate without applied voltage. By using dopants, including but not limited to B and N, the cathode potential can be shifted to more positive values ​​and the anode potential can be shifted to more negative values. The hydrogen production reaction can occur spontaneously without any external power. The voltage for hydrogen reduction is much more positive than the oxidation of hydrazine or urea under low pH values ​​on the cathode side of the electrolysis cell and high pH values ​​on the anode side of the electrolysis cell. The low pH value can be at least about 0, about 0 to about 5.5, about 2.5 to about 5, about 2.5 to about 4.5, about 3 to about 4, or about 5.5. The high pH value can be at least about 8, about 8 to about 14, about 9 to about 13, about 10 to about 12, or about 14. At this time, hydrogen production becomes thermodynamically favorable and occurs spontaneously as long as the concentrations of salts on both sides are maintained. Thus, the nitrogen-compound-assisted hydrogen electrolyzer can function autonomously to produce gaseous hydrogen and can also generate electricity. -2 High electrolytic cell current densities can result from the incorporation of metal or mixed metal-metal oxide nanoparticles into the electrodes.

[0093] The electrolytic cell system may include an anode cell and / or a cathode cell. The overall potential of the anode cell is about 10 mA cm -2 The overall potential in the cathodic cell may be less than about 250 mV, about 250 mV to about 0 mV, about 225 mV to about 10 mV, about 200 mV to about 50 mV, about 150 mV to about 100 mV, or about 250 mV at a current density of 10 mA cm. -2 At a current density of about 100 mV, the potential may be less than about 100 mV, about 0 mV to about 100 mV, about 5 mV to about 99 mV, about 10 mV to about 97 mV, about 15 mV to about 95 mV, about 20 mV to about 90 mV, about 30 mV to about 80 mV, about 40 mV to about 70 mV, about 50 mV to about 60 mV, or about 100 mV.

[0094] The cathode and anode may comprise the same material composition, i.e., function as a dual-function electrode, or may comprise different material compositions, e.g., function as separate electrodes. Dual-function electrodes can have higher stability than separate electrodes, because there is no difference in electrode composition, reducing or avoiding the risk of galvanic cell coupling and subsequent electrode corrosion and degradation. A Pt electrode with a cell voltage of less than 100 mV can serve as the performance benchmark for both the anode and the cathode.

[0095] The microstructured and / or nanostructured foams may include microstructured and / or nanostructured catalysts that include metal or mixed metal-metal oxide nanoparticles. The metal or mixed metal-metal oxide may be applied to the microstructured and / or nanostructured foams using physical or chemical deposition methods, including but not limited to magnetron sputtering, plasma coating, electrolytic coating, or combinations thereof. The metals may include, but are not limited to, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Nb, Mo, Ru, Pd, Ag, Cd, Hf, Ta, W, Re, Ir, Pt, Au, or combinations thereof. The metal oxides may be oxides made from the above metals. [Industrial Applicability]

[0096] The invention is further illustrated by the following non-limiting examples. EXAMPLES

[0097] Example 1 The deposition of the compound material on the substrate was performed by sputtering. After cleaning, the substrate was placed in a sputtering chamber (various models, such as DC, RF, or magnetron, were tested without problems) and was then subjected to about 10 -6 The test base pressure was 1.2 MPa (1.0 MPa) and 1.2 MPa (1.0 MPa) for 100 s.p.m. The main catalyst and roughening materials were (IrO x , NiN, NiO xN) in an argon atmosphere or an argon / oxygen / nitrogen atmosphere at an operating pressure of about 3-9 milliTorr, using a sputtering power in the range of 25-500 W and a gas flow rate in the range of 1-100 standard cubic centimeters. Example 2

[0098] The deposition of the compound materials onto the substrate was performed by electrochemical deposition. There were several different methods. In one aspect, the electrochemical method was performed by using a pulse electrodeposition method or by forming a core-shell structure (roughened material as the core and the main catalyst as the shell). The temperature of the bath used for the electrochemical method was maintained using a constant temperature thermostat. The solutions were freshly prepared using DI water and AnalaR grade chemicals. Tables 1 and 2 show examples of the solutions and salts used for the electrochemical deposition. [Table 1] [Table 2]

[0099] Example 3 Electrodeposition of materials was performed using direct and pulsed currents by a potentiostat. The current value and time depended on the coating thickness and morphology as well as the targeted particle size range. Electroplating times ranged from 15 min to 1 h. The applied current was 75 mA / cm 2 ~500mA / cm 2 The pulse method had a range of t on = 50μs~5000μs, t off A square wave of =10μs~1000μs was used. Example 4

[0100] Post-processing of the compound material deposited on the substrate was performed by leaching and doping. The microstructure of the catalytic material was formed by leaching of the roughened material from the compound material. This process was performed by selective etching, where only certain materials are etched with negligible effect on other materials in the system.

[0101] The foregoing examples may be repeated with similar success using the generically or specifically described components and / or operating conditions of embodiments of the invention in place of those used in the foregoing examples.

[0102] It is noted that, in this specification and claims, "about" or "approximately" means within twenty percent (20%) of a given amount or value.

[0103] An embodiment of the present invention may include any combination of the features disclosed herein independent of each other. Although the present invention has been described in detail with particular reference to the disclosed embodiments, other embodiments may achieve the same results. Variations and modifications of the present invention will be apparent to those skilled in the art, and it is intended to cover all such modifications and equivalents in the scope of the appended claims. The entire disclosures of all references, applications, patents, and publications cited above are incorporated herein by reference. Unless specifically stated above as "essential," none of the various components or their interrelationships are essential to the operation of the present invention. Rather, desired results can be achieved by substituting the various components and / or rearranging their relationships with one another.

Claims

1. A system for electrolyzing a solution, comprising: ・ A compound containing at least one kind of catalyst material, and ・ A microporous structure, At least one electrode having the same, At least one separator, A first container communicating with at least one electrolytic cell stack including the same, and A second container communicating with the at least one electrolytic cell stack, A system.

2. The system according to claim 1, wherein the at least one kind of catalyst material contains PGM.

3. The system according to claim 1 or 2, wherein the at least one kind of catalyst material contains nickel.

4. The system according to claim 1, wherein the at least one kind of catalyst material contains cobalt.

5. The system according to claim 1, further comprising at least one membrane.

6. The system according to claim 1, wherein the at least one electrode further comprises a roughening material.

7. The system according to claim 6, wherein the roughening material contains aluminum.

8. The system according to claim 1, wherein the at least one electrode further comprises a nanoporous structure.

9. The system according to claim 1, wherein the at least one electrode further comprises at least one kind of doping agent.

10. A method for decomposing water in a solution, comprising: Passing a solution containing at least one kind of nitrogen compound through at least one electrolytic cell stack; ・ At least one kind of catalyst material, and ・ A microporous structure, Bringing the solution into contact with at least one electrode having the same; Decomposing water molecules in the solution to generate hydrogen gas, nitrogen gas, and oxygen gas; Separating the oxygen gas or the nitrogen gas from the hydrogen gas; Discharging the hydrogen gas from the at least one electrolytic cell stack; Collecting the hydrogen gas. A method including the above.

11. The method according to claim 10, further comprising applying a current to the electrode.

12. A method for manufacturing an electrode, comprising: Preparing a substrate; Washing the substrate; Bringing the substrate into contact with an acidic solution; Applying a current to the substrate; Drying or rinsing the substrate; Simultaneously depositing at least one kind of supporting material containing a roughening material and at least one kind of main material on the substrate; Performing a leaching treatment on the at least one roughening material deposited on the substrate. A method comprising...

13. The method according to claim 12, wherein the main material contains nickel.

14. The method according to claim 12 or 13, wherein the main material contains PGM.

15. The method according to claim 12, wherein the main material contains cobalt.

16. The method according to claim 12, wherein the at least one supporting material contains aluminum.

17. The method according to claim 12, wherein the at least one supporting material contains a doping agent.

18. The method according to claim 12, wherein depositing the at least one material includes physical deposition.

19. The method according to claim 12, wherein depositing the at least one material includes chemical deposition.

20. A substrate, A porous structure in contact with the substrate, - A main material, - A supporting material, and - Pores having a diameter sufficient to receive atoms of the supporting material, The porous structure having, A doping agent, An electrode comprising.

21. The electrode according to claim 20, wherein the porous structure contains micropores.

22. The electrode according to claim 20 or 21, wherein the porous structure contains nanopores.

23. The electrode according to claim 20, wherein the main material and the supporting material account for at least 25% of the weight of the substrate.

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