Durable non-ir metal oxide and metal alloy materials, and uses thereof

Abstract

Provided are compositions comprising a catalytic oxide material having the atomic formula of M1xM2yM3zM4tM5uOv; and / or a catalytic alloy material having the atomic formula of M1xM2yM3zM4tM5u, where M1, M2, M3, M4 and M5 are selected from Ru, Ni, W, Nb, Mn, Fe, Ti, Ag, V, Co, and Mo. Further provided is the use of the catalytic oxide materials and / or the catalytic alloy materials in oxygen evolution reactions.

Description

Attorney Docket No.00172-003WO1 DURABLE NON-Ir METAL OXIDE AND METAL ALLOY MATERIALS, AND USES THEREOF CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority under 35 U.S.C. §119(e) to U.S. Provisional Application No. 63 / 684,272, filed August 16, 2024, the disclosures of which are incorporated herein by reference for all purposes. FIELD OF THE INVENTION

[0002] The disclosure relates to catalytic materials, and more specifically, to electrocatalytic materials. BACKGROUND

[0003] The oxygen evolution reaction (OER) is of crucial importance for various applications, including fuel generation, electrowinning, and carbon storage. The amount of voltage beyond that which is thermodynamically required to achieve current flow for OER is termed overpotential. To improve the efficiency of a system which requires OER, overpotential should be minimized. OER in acid is uniquely difficult to achieve due to unfavorable energetics for many materials, and poor durability under operating conditions; in most cases expensive iridium and ruthenium materials are used in such systems. As a result, there is a need for improved OER catalytic materials with high activity and a decreased amount of iridium / ruthenium loading. The catalytic materials described in this disclosure contain no iridium. SUMMARY

[0004] The disclosure describes compositions comprising, consisting essentially of, or consisting of, a class of catalytic mixed metal oxide materials that are effective at low overpotentials. Additionally, the catalytic mixed metal oxide materials of the disclosure are tolerant of highly acidic environments such as environments with a pH less than 3, 1, or 0. The catalytic mixed metal oxide materials of the disclosure serve as oxidation catalysts and can accordinglyAttorney Docket No.00172-003WO1 catalyze a variety of reactions such as the Oxygen Evolution Reaction, the Oxygen Reduction Reaction, and redox reactions for flow batteries. In particular, the catalysts are ideally suited to catalyze the Oxygen Evolution Reaction. Catalysts for the oxygen evolution reaction are often placed in an environment with very low pH levels for applications such as electrowinning and electrolytic hydrogen evolution. However, the catalysts that are used in highly acidic conditions typically are comprised of very expensive components such as iridium and ruthenium oxides in large amounts. By limiting these components, the price associated with these catalysts can be substantially reduced. Accordingly, an oxygen evolution system can include one or more electrodes exposed to an environment with a pH less than 3, 1, or 0 where the electrode includes an oxygen evolution reaction catalyst that excludes expensive metals like iridium, rhodium, palladium, silver, osmium, platinum, gold, and rhenium.

[0005] In a particular embodiment, the disclosure provides for a composition comprising a catalytic oxide material that contains Ru, Ni, W, Nb, Mn, and oxygen. In another embodiment, the disclosure provides for a composition comprising a catalytic oxide material that contains Ru, Fe, Ti, Ag, W, and oxygen. In yet another embodiment, the disclosure provides for a composition comprising a catalytic oxide material that contains Ru, Fe, Ti, Nb, W, and oxygen. In another embodiment, the disclosure provides for a composition comprising a catalytic oxide material that contains Ru, Ti, V, Co, W, and oxygen. In another embodiment, the disclosure provides for a composition comprising a catalytic oxide material that contains Fe, Mn, Mo, W, Nb, and oxygen. In another embodiment, the disclosure provides for a composition comprising a catalytic alloy material that contains Ru, Co, V, W, and Ti. In another embodiment, the disclosure provides for a composition comprising a catalytic alloy material thatAttorney Docket No.00172-003WO1 contains Ru, Fe, Co, V, and Ti in a metallic alloy mixture.

[0006] In a particular embodiment, the disclosure provides a composition comprising: a catalytic oxide material having the atomic formula of M1xM2yM3zM4tM5uOv; and / or a catalytic alloy material having the atomic formula of M1xM2yM3zM4tM5u,wherein, M1, M2, M3, M4 and M5 are different metals, and wherein M1, M2, M3, M4 and M5 are selected from Ru, Ni, W, Nb, Mn, Fe, Ti, Ag, V, Co, and Mo; wherein x+y+z+t+u=1; and wherein the catalytic oxide material and the catalytic alloy material have electrochemical activity in an acidic environment. In a further embodiment, one of M1, M2, M3, M4 and M5 is Ru or Fe. In yet a further embodiment, one of M1, M2, M3, M4 and M5 is W or V. In another embodiment, the composition comprises a catalytic oxide material where the metals making up M1xM2yM3zM4tM5uOvare selected from one of the following: (a) Ru, Ni, W, Nb, Mn, and O; (b) Ru, Fe, Ti, Ag, W, and O; (c) Ru, Fe, Ti, Nb, W, and O; (d) Ru, Ti, V, Co, W, and O; and (e) Fe, Mn, Mo, W, Nb, and O. In another embodiment, the amount of oxygen in the catalytic oxide material results from annealing the catalytic oxide material in air to a temperature from 500 °C to 700 °C. In yet another embodiment, M1xM2yM3zM4tM5uOvis RuxNiyWzNbtMnuOvwhere 0.09≤x≤0.54, 0.12≤y≤0.31, 0.11≤z≤0.26, 0.04≤t≤0.17, 0.16≤u≤0.23 and the oxygen fraction v is the number required in the lattice after annealed to 700˚C in air. In a further embodiment, M1xM2yM3zM4tM5uOvis RuxFeyTizAgtWuOvwhere 0.08≤x≤0.34, 0.03≤y≤0.18, 0.12≤z≤0.77, 0.08≤t≤0.47, 0.02≤u≤0.13 and the oxygen fraction v is the number required in the lattice after annealed to 500˚C in air. In yet a further embodiment, M1xM2yM3zM4tM5uOvis RuxFeyTizNbtWuOvwhere 0.16≤x≤0.45, 0.03≤y≤0.30, 0.14≤z≤0.29, 0.02≤t≤0.10, 0.09≤u≤0.45 and the oxygen fraction v is the number required in the lattice after annealed to 600˚C in air. In another embodiment, M1xM2yM3zM4tM5uOvis RuxTiyVzCotWuOvwhere 0.06≤x≤0.26,Attorney Docket No.00172-003WO1 0.16≤y≤0.27, 0.14≤z≤0.33, 0.12≤t≤0.28, 0.17≤u≤0.26 and the oxygen fraction v is the number required in the lattice after annealed to 500˚C in air. In yet another embodiment, M1xM2yM3zM4tM5uOvis FexMnyMozWtNbuOvwhere 0.20≤x≤0.48, 0.21≤y≤0.40, 0.05≤z≤0.14, 0.12≤t≤0.23, 0.04≤u≤0.14 and the oxygen fraction v is the number required in the lattice after annealed to 700˚C in air. In a certain embodiment, the composition comprises a catalytic alloy material where the metals making up M1xM2yM3zM4tM5uis selected from one the following: (i) Ru, Co, V, W, and Ti; and (ii) Ru, Fe, Co, V, and Ti. In a further embodiment, the catalytic alloy material is annealed to a temperature from 500 °C to 700 °C in a reducing environment. In yet a further embodiment, the reducing environment comprises a mixture of hydrogen and argon gases. In another embodiment, M1xM2yM3zM4tM5uis RuxCoyVzWtTiuwhere 0.08≤x≤0.23, 0.12≤y≤0.27, 0.15≤z≤0.46, 0.12≤t≤0.21, 0.09≤u≤0.30 and the catalytic alloy material is annealed to 650˚C in a reducing environment. In yet another embodiment, where M1xM2yM3zM4tM5uis RuxFeyCozVtTiuwhere 0.14≤x≤0.26, 0.18≤y≤0.28, 0.10≤z≤0.16, 0.17≤t≤0.42, 0.04≤u≤0.23 and the catalytic alloy material is annealed to 650˚C in a reducing environment.

[0007] In one embodiment, a catalytic oxide material comprises oxygen, Ru, Ni, W, Nb, and Mn in proportions such that the compound is described compositionally as RuxNiyWzNbtMnuOvwhere x+y+z+t+u =1; 0.09≤x≤0.54, 0.12≤y≤0.31, 0.11≤z≤0.26, 0.04≤t≤0.17, 0.16≤u≤0.23 and the oxygen fraction v is the number required in the lattice after the combination is annealed to 700˚C in air.

[0008] In another embodiment, a catalytic oxide material comprises oxygen, Ru, Fe, Ti, Ag, and W in proportions such that the compound is described compositionally as RuxFeyTizAgtWuOvwhere x+y+z+t+u =1; 0.08≤x≤0.34, 0.03≤y≤0.18, 0.12≤z≤0.77, 0.08≤t≤0.47, 0.02≤u≤0.13 and the oxygen fractionAttorney Docket No.00172-003WO1 v is the number required in the lattice after the combination is annealed to 500˚C in air.

[0009] In another embodiment, a catalytic oxide material comprises oxygen, Ru, Fe, Ti, Nb, and W in proportions such that the compound is described compositionally as RuxFeyTizNbtWuOvwhere x+y+z+t+u =1; 0.16≤x≤0.45, 0.03≤y≤0.30, 0.14≤z≤0.29, 0.02≤t≤0.10, 0.09≤u≤0.45 and the oxygen fraction v is the number required in the lattice after the combination is annealed to 600˚C in air.

[0010] In another embodiment, a catalytic oxide material comprises oxygen, Ru, Ti, V, Co, and W in proportions such that the compound is described compositionally as RuxTiyVzCotWuOvwhere x+y+z+t+u =1; 0.06≤x≤0.26, 0.16≤y≤0.27, 0.14≤z≤0.33, 0.12≤t≤0.28, 0.17≤u≤0.26 and the oxygen fraction v is the number required in the lattice after the combination is annealed to 500˚C in air.

[0011] In another embodiment, a catalytic oxide material comprises oxygen, Fe, Mn, Mo, W, and Nb in proportions such that the compound is described compositionally as FexMnyMozWtNbuOvwhere x+y+z+t+u =1; 0.20≤x≤0.48, 0.21≤y≤0.40, 0.05≤z≤0.14, 0.12≤t≤0.23, 0.04≤u≤0.14 and the oxygen fraction v is the number required in the lattice after the combination is annealed to 700˚C in air.

[0012] In another embodiment, a catalytic alloy material comprises Ru, Co, V, W, and Ti in proportions such that the compound is described compositionally as RuxCoyVzWtTiuwhere x+y+z+t+u =1; 0.08≤x≤0.23, 0.12≤y≤0.27, 0.15≤z≤0.46, 0.12≤t≤0.21, 0.09≤u≤0.30 and the combination is annealed to 650˚C in a reducing environment.

[0013] In another embodiment, a catalytic alloy material comprises Ru, Fe, Co, V, and Ti in proportions such that the compound is described compositionally as RuxFeyCozVtTiuwhere x+y+z+t+u =1; 0.14≤x≤0.26, 0.18≤y≤0.28, 0.10≤z≤0.16, 0.17≤t≤0.42, 0.04≤u≤0.23 and the combination is annealed toAttorney Docket No.00172-003WO1 650˚C in a reducing environment.

[0014] In a particular embodiment, the disclosure also provides an electrode comprising a composition comprising a catalytic oxide material, and / or catalytic alloy material disclosed herein. In a further embodiment, the electrode is part of an oxygen evolution system, and wherein the electrode catalyzes the oxidation of water to oxygen gas. In yet a further embodiment, the composition functions at the surface of the electrode, defines the surface or the electrode, or interacts with one or more components or the environment in which the electrode is positioned.

[0015] In a certain embodiment, the disclosure also provides a method for electrolyzing water, comprising: contacting an aqueous medium with an anode and a cathode, wherein the anode comprises a catalytic oxide material, and / or catalytic alloy material disclosed herein; and applying a voltage to provide a current density to cause water in the aqueous solvent to be electrochemically split to form oxygen and hydrogen. In a further embodiment, the aqueous medium has a pH of less than 5 and the volage is applied under anodic conditions. In yet a further embodiment, the aqueous medium comprises sulfuric acid. In a certain embodiment, the disclosure provides a water electrolysis system that comprises one or more water electrolysis cells, wherein the water electrolysis cell comprises: a proton-exchange membrane that a portion of which is coated on one side with one or more anode layers, and coated on the opposite side with one or more cathode layers, wherein anode layers comprise composition comprising a catalytic oxide material, and / or catalytic alloy material disclosed herein; an anode gas-diffusion layer in fluid contact with the one or more anode layers; a cathode gas- diffusion layer in fluid contact with the one or more cathode layers; a plurality of gaskets that prevent the flow of fluidsAttorney Docket No.00172-003WO1 and ions across the proton exchange membrane which is not coated by the one or more anode layers or the one or more cathode layers; and an anode separator and a cathode separator comprising channels for a fluid comprising water, and wherein the anode separator is in fluid contact with the anode gas- diffusion layer, and the cathode separator is in fluid contact with the anode gas-diffusion layer. The water electrolysis system of claim 22, wherein the water electrolysis system comprises at least ten or more water electrolysis cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] FIG. 1 provides a geometric plot indicating the electrochemical activity of the metal oxides comprising Ru, Ni, W, Nb, Mn, and oxygen, in 1M sulfuric acid after durability testing. Darker colors indicate active catalysts. The grid fully comprises the composition ranges disclosed herein.

[0017] FIG. 2 provides geometric plot indicating the electrochemical activity of the metal oxides comprising Ru, Fe, Ti, Ag, W, and oxygen, in 1M sulfuric acid after durability testing. Darker colors indicate active catalysts. The grid comprises the composition ranges disclosed herein.

[0018] FIG. 3 provides a geometric plot indicating the electrochemical activity of the metal oxides comprising Ru, Fe, Ti, Nb, W, and oxygen, in 1M sulfuric acid after durability testing. Darker colors indicate active catalysts. The grid comprises the composition ranges disclosed herein.

[0019] FIG. 4 provides a geometric plot indicating the electrochemical activity of the metal oxides comprising Ru, Ti, V, Co, W, and oxygen, in 1M sulfuric acid after durability testing. Darker colors indicate active catalysts. The grid comprises the composition ranges disclosed herein.

[0020] FIG. 5 provides a geometric plot indicating the electrochemical activity of the metal oxides comprising Fe, Mn, Mo, W, Nb, and oxygen, in 1M sulfuric acid afterAttorney Docket No.00172-003WO1 durability testing. Darker colors indicate active catalysts. The grid comprises the composition ranges disclosed herein.

[0021] FIG. 6 provides a geometric plot indicating the electrochemical activity of the metal oxides comprising Ru, Co, V, W, and Ti, in 1M sulfuric acid after durability testing. Darker colors indicate active catalysts. The grid comprises the composition ranges disclosed herein.

[0022] FIG. 7 provides a geometric plot indicating the electrochemical activity of the metal oxides comprising Ru, Fe, Co, V, and Ti in 1M sulfuric acid after durability testing. Darker colors indicate active catalysts. The grid comprises the composition ranges disclosed herein.

[0023] FIG. 8A provides a perspective view of an electrode that can include an oxidation catalyst such as an oxygen evolution catalyst.

[0024] FIG. 8B provides a schematic showing an electrode comprising a catalyst material of the disclosure.

[0025] FIG. 9A is a diagram illustrating an electrolysis system.

[0026] FIG. 9B provides a schematic showing a water electrolysis cell that comprises a proton exchange membrane comprising a coating of a catalyst material of the disclosure. DETAILED DESCRIPTION

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. In case of conflict, the present document, including definitions, will control. Preferred methods and materials are described below, although methods and materials similar or equivalent to those described herein can be used in practice or testing of the present invention. All publications, patent applications, patents and other references mentioned herein are incorporated by reference herein in their entirety.

[0028] The materials, methods, and examples disclosedAttorney Docket No.00172-003WO1 herein are illustrative only and not intended to be limiting. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting.

[0029] The singular forms “a,” “an” and “the” include plural references unless the context clearly dictates otherwise.

[0030] The terms “comprise(s),” “include(s),” “having,” “has,” “can,” “contain(s),” “may” and variants thereof, as used herein, are intended to be open-ended transitional phrases, terms, or words that do not preclude the possibility of additional acts or structures.

[0031] The present disclosure also contemplates other embodiments “comprising,” “consisting of” and “consisting essentially of,” the embodiments or elements presented herein, whether explicitly set forth or not.

[0032] The word “exemplary” is used throughout this application to mean “serving as an example, instance, or illustration.” Any system, method, device, technique, feature or the like described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other features.

[0033] Also, the use of “or” means “and / or” unless slated otherwise. Similarly, “comprise,” “comprises," “comprising” “include,” “includes,” and “including” are interchangeable and not intended to be limiting.

[0034] The disclosure provides compositions that comprises, consists essentially of, or consists of various catalysts containing five metals and oxygen to create a composition with atomic formula M1xM2yM3zM4tM5uOv, and the synthesis thereof. The disclosure also provides compositions that comprises, consists essentially of, or consists of various catalysts containing five metals to create an alloy composition with atomic formula M1xM2yM3zM4tM5u, and synthesis thereof. While variousAttorney Docket No.00172-003WO1 formulations of the composition are disclosed herein, compositional values were found herein that exhibited superior catalytic activity for the oxygen evolution reaction (OER). In the studies presented herein, it was found for specific compositions described herein, the OER may be undertaken at low overpotentials in acidic media. As a result, the catalysts are an effective and cost-effective replacement for a purely Ir or purely Ir / Ru catalyst.

[0035] In a particular embodiment, the disclosure provides for a composition that comprises, consists essentially of, or consists of an oxidation catalyst having oxygen, Ru, Ni, W, Nb, and Mn in proportions such that the compound is described compositionally as RuxNiyWzNbtMnuOvwhere x+y+z+t+u=1. In one embodiment, the catalyst is synthesized by directly co- sputtering a plasma mixture containing atoms of each of the constituent elements on the target surface or substrate in a partial oxygen or oxygen-free environment. For example, sputter can comprise depositing onto a platinized alumina surface in a 100% Argon gas environment with a pressure of 8 mTorr for 20 minutes. The power applied to each sputter target to deliver the plasma is: Ru – 50 Watts (W), Mn – 40W, Ni – 30W, W / Nb bimetallic target - 100 W. The catalyst is then annealed at about 700 °C (e.g., 500 °C to 900 °C, or any temperature therebetween) in ambient air to provide the catalyst in a substantially pure (e.g., 90-100% pure, or any percent therebetween) metal oxide form. As demonstrated herein, the catalyst can be subjected to durability testing in acidic media under anodic conditions to ensure the durability of the material. Specific values of x, y, z, t and u which return suitable electrochemical activity and stability, are shown in FIG. 1, and include 0.09≤x≤0.54, 0.12≤y≤0.31, 0.11≤z≤0.26, 0.04≤t≤0.17, 0.16≤u≤0.23 and the oxygen fraction v is the number required in the lattice after the combination is annealed at about 700 °C in air.Attorney Docket No.00172-003WO1

[0036] In a certain embodiment, the disclosure also provides a composition that comprises, consists essentially of, or consists of an oxidation catalyst including oxygen, Ru, Fe, Ti, Ag, and W in proportions such that the compound is described compositionally as RuxFeyTizAgtWuOvwhere x+y+z+t+u =1. The catalyst can be synthesized by directly co-sputtering a plasma mixture containing atoms of each of the constituent elements on a target surface or substrate in a partial oxygen or oxygen-free environment. For example, sputter can comprise depositing onto a platinized alumina surface in a 100% Argon gas environment with a pressure of 8 mTorr for 20 minutes. The power applied to each sputter target to deliver the plasma is: Ru – 40 Watts (W), Fe – 30W, Ag – 80W, W / Ti bimetallic target - 100 W. The catalyst is then annealed at about 500 °C (e.g., 300 °C to 700 °C, or any temperature therebetween) in air to provide the catalyst in a substantially pure metal oxide form. The catalyst can then be subjected to durability testing in acidic media under anodic conditions to ensure the durability of the material. Specific values of x, y, z, t and u which return the highest electrochemical activity and stability, are shown in FIG. 2, and include 0.08≤x≤0.34, 0.03≤y≤0.18, 0.12≤z≤0.77, 0.08≤t≤0.47, 0.02≤u≤0.13 and the oxygen fraction v is the number required in the lattice after the combination is annealed at about 500 °C in air.

[0037] In a particular embodiment, the disclosure further provides a composition that comprises, consists essentially of, or consists of an oxidation catalyst including oxygen, Ru, Fe, Ti, Nb, and W in proportions such that the compound is described compositionally as RuxFeyTizNbtWuOvwhere x+y+z+t+u=1. The catalyst can be synthesized by directly co-sputtering a plasma mixture containing atoms of each of the constituent elements on a target surface or substrate in a partial oxygen or oxygen-free environment. For example, sputter can comprise depositing onto a platinized alumina surface in a 100% ArgonAttorney Docket No.00172-003WO1 gas environment with a pressure of 8 mTorr for 20 minutes. The power applied to each sputter target to deliver the plasma is: Ru – 40 Watts (W), Fe – 30W, W / Ti bimetallic target – 100W, W / Nb bimetallic target - 100 W. The catalyst is then annealed at about 600 °C (e.g., 400 °C to 800 °C, or any temperature therebetween) in air to provide the catalyst in a substantially pure metal oxide form. This catalyst can then be subjected to durability testing in acidic media under anodic conditions to ensure the durability of the material. Specific values of x, y, z, t and u which return the highest electrochemical activity and stability, are shown in FIG. 3, and include 0.16≤x≤0.45, 0.03≤y≤0.30, 0.14≤z≤0.29, 0.02≤t≤0.10, 0.09≤u≤0.45 and the oxygen fraction v is the number required in the lattice after the combination is annealed at about 600°C in air.

[0038] In a particular embodiment, the disclosure provides a composition that comprises, consists essentially of, or consists of an oxidation catalyst having oxygen, Ru, Ti, V, Co, and W in proportions such that the compound is described compositionally as RuxTiyVzCotWuOvwhere x+y+z+t+u=1. The catalyst can be synthesized by directly co-sputtering a plasma mixture containing atoms of each of the constituent elements on a target surface or substrate in a partial oxygen or oxygen-free environment. For example, sputter can comprise depositing onto a platinized alumina surface in a 100% Argon gas environment with a pressure of 8 mTorr for 20 minutes. The power applied to each sputter target to deliver the plasma is: Ru – 30 Watts (W), Co – 30W, V – 80W, W / Ti bimetallic target - 110 W. The catalyst is then annealed at about 500 °C (e.g., 300 °C to 700 °C, or any temperature therebetween) in air to provide the catalyst in a substantially pure metal oxide form. This catalyst can then be subjected to durability testing in acidic media under anodic conditions to ensure the durability of the material. Specific values of x, y, z, t and u whichAttorney Docket No.00172-003WO1 return suitable electrochemical activity and stability, are shown in FIG. 4, and include 0.06≤x≤0.26, 0.16≤y≤0.27, 0.14≤z≤0.33, 0.12≤t≤0.28, 0.17≤u≤0.26 and the oxygen fraction v is the number required in the lattice after the combination is annealed at about 500 °C in air.

[0039] In a certain embodiment, the disclosure also provides a composition that comprises, consists essentially of, or consists of an oxidation catalyst having oxygen, Fe, Mn, Mo, W, and Nb in proportions such that the compound is described compositionally as FexMnyMozWtNbuOvwhere x+y+z+t+u=1. The catalyst can be synthesized by directly co-sputtering a plasma mixture containing atoms of each of the constituent elements on a target surface or substrate in a partial oxygen or oxygen-free environment. For example, sputter can comprise depositing onto a platinized alumina surface in a 100% Argon gas environment with a pressure of 8 mTorr for 20 minutes. The power applied to each sputter target to deliver the plasma is: Fe – 50 Watts (W), Mn – 40W, Mo – 100W, W / Nb bimetallic target - 120 W. The catalyst is then annealed at about 700 °C (e.g., 500 °C to 900 °C, or any temperature therebetween) in air to provide the catalyst in a substantially pure metal oxide form. This catalyst can then be subjected to durability testing in acidic media under anodic conditions to ensure the durability of the material. Specific values of x, y, z, t and u which return the suitable electrochemical activity and stability, are shown in FIG. 5, and include 0.20≤x≤0.48, 0.21≤y≤0.40, 0.05≤z≤0.14, 0.12≤t≤0.23, 0.04≤u≤0.14 and the oxygen fraction v is the number required in the lattice after the combination is annealed at about 700 °C in air.

[0040] In a particular embodiment, the disclosure further provides a composition that comprises, consists essentially of, or consists of an oxidation catalyst includes Ru, Co, V, W, and Ti in proportions such that the compound is described compositionally as RuxCoyVzWtTiuwhere x+y+z+t+u=1. The catalystAttorney Docket No.00172-003WO1 can be synthesized by directly co-sputtering a plasma mixture containing atoms of each of the constituent elements on a target surface or substrate in an oxygen-free environment. For example, sputter can comprise depositing onto a platinized alumina surface in a 100% Argon gas environment with a pressure of 8 mTorr for 20 minutes. The power applied to each sputter target to deliver the plasma is: Ru – 30 Watts (W), Co – 40W, V – 80W, W / Ti bimetallic target - 110 W. The catalyst is then annealed at about 650 °C (e.g., 450 °C to 850 °C, or any temperature therebetween) in a reducing environment (H2 / Ar) to provide the catalyst in a substantially pure metal alloy form. This catalyst can then be subjected to durability testing in acidic media under anodic conditions to ensure the durability of the material. Specific values of x, y, z, t and u which return the highest electrochemical activity and stability, are shown in FIG. 6, and include 0.08≤x≤0.23, 0.12≤y≤0.27, 0.15≤z≤0.46, 0.12≤t≤0.21, 0.09≤u≤0.30. After durability testing in acidic media, it is understood that the metallic catalyst has a surface oxide layer.

[0041] In a certain embodiment, the disclosure further provides a composition that comprises, consists essentially of, or consists of an oxidation catalyst includes Ru, Fe, Co, V, and Ti in proportions such that the compound is described compositionally as RuxFeyCozVtTiuwhere x+y+z+t+u=1. The catalyst can be synthesized by directly co-sputtering a plasma mixture containing atoms of each of the constituent elements on a target surface or substrate in an oxygen-free environment. For example, sputter can comprise depositing onto a platinized alumina surface in a 100% Argon gas environment with a pressure of 8 mTorr for 20 minutes. The power applied to each sputter target to deliver the plasma is: Ru – 50 Watts (W), Fe – 50W, Co – 40W, V – 70W, Ti - 60 W. The catalyst is then annealed at about 650 °C (e.g., 450 °C to 850 °C, or any temperature therebetween) in reducing environment (H2 / Ar) toAttorney Docket No.00172-003WO1 provide a catalyst in a substantially pure metal alloy form. This catalyst can then be subjected to durability testing in acidic media under anodic conditions to ensure the durability of the material. Specific values of x, y, z, t and u which return the highest electrochemical activity and stability, are shown in FIG. 7, and include 0.14≤x≤0.26, 0.18≤y≤0.28, 0.10≤z≤0.16, 0.17≤t≤0.42, 0.04≤u≤0.23. After durability testing in acidic media, it is understood that the metallic catalyst has a surface oxide layer.

[0042] The above catalysts serve as oxidation catalysts and can accordingly catalyze a variety of reactions such as the Oxygen Evolution Reaction, the Oxygen Reduction Reaction, and redox reaction for flow batteries. In particular, the catalysts can catalyze the Oxygen Evolution Reaction (OER). The Oxygen Evolution Reaction is where oxygen gas is evolved from water or other oxides. One example of the oxygen evolution reaction is the oxidation of water represented by: 2H2O^ O2+4H++4e-. Another example of the oxygen evolution reaction is 4OH- ^ O2+ 2H2O + 4e-.

[0043] The catalyst can be an electrocatalyst. For instance, the catalyst can have one, two or three features selected from the following: functions at the surface of an electrode, defines the surface or the electrode, or interacts with one or more components or the environment in which the electrode is positioned. In some instances, the catalyst catalyzes oxygen evolution at the surface of an electrode and / or oxidizes water that is present in the environment in which the electrode is positioned.

[0044] In a particular embodiment, the disclosure provides for an electrode comprising a composition comprising a catalytic oxide material and / or catalytic alloy material disclosed herein. In a further embodiment, the composition functions at the surface of the electrode, defines the surface or the electrode, or interacts with one or more components orAttorney Docket No.00172-003WO1 the environment in which the electrode is positioned. In yet a further embodiment, the electrode is part of an oxygen evolution system, and wherein the electrode catalyzes the oxidation of water to oxygen gas. In yet another embodiment, the electrode is part of a fuel generation system or a fuel storage system. In another embodiment, the electrode is part of an electrowinning system. In yet another embodiment, the electrode is part of an electrolytic hydrogen generator, a solar fuels generator, reversible fuel cell, or reversible air batteries.

[0045] FIG. 8A is a perspective view of an electrode that includes a catalyst of the disclosure. The electrode includes a catalytic layer 4 on an electrode base (target surface / substrate) 5. The catalytic layer 4 includes, consists of, or consists essentially of one or more of the catalysts having the general formula M1xM2yM3zM4tM5uOvand / or M1xM2yM3zM4tM5u. The catalytic layer 4 can include components in addition to the one or more catalysts. For instance, the catalytic layer 4 can include one or more components selected from the group consisting of binders, polymers, membranes, electrical conductors, ionic conductors, solid electrolytes, porous materials, and inert support materials. The electrode base 5 represents the portion of the electrode having a traditional electrode construction. Alternately, the electrode base 5 represents the portion of the electrode having a traditional electrode construction but with a prior catalytic layer removed from the electrode. Accordingly, the catalytic layer 4 can be added to a prior art electrode or can replace a catalytic layer 4 on a prior art electrode.

[0046] The electrode base 5 can be a current collector such as a metal foil or sheet, mesh, or conducting fabric. As will become evident from the below illustration, the electrode base 5 can be or include a photoactive layer. For instance, the electrode base 5 can include or consist of a material thatAttorney Docket No.00172-003WO1 absorbs light and converts the absorbed light into excited electron-hole pairs that drive a chemical reaction such as electrolysis of water. Although the electrode base 5 is shown as a single layer of material, the electrode base 5 can include multiple layers of material. For instance, the electrode base 5 can include one or more layers of active material on a current collector. In instance where the electrode is employed to oxidize water, the electrode operates as an anode. During fabrication of the electrode, in some instances, the electrode base serves as the support or substrate for the catalyst. Accordingly, the catalyst can be formed directly on the electrode base.

[0047] Although the catalytic layer 4 is illustrated as being located on one side of the electrode base 5, the catalytic layer 4 can be located on both sides of the electrode base. Additionally or alternately, the electrode base 5 can be embedded in the catalytic layer 4. For instance, electrode base 5 can be a mesh that is embedded in the catalytic layer 4. Although FIG. 8A illustrates the catalytic layer 4 as a continuous layer of material, the catalytic layer 4 can be patterned so there are openings through the catalytic layer 4 and / or so there are regions of the catalytic layer 4 that are not continuous with one another, such as would occur when the catalytic layer 4 is arranged in islands on the electrode base. Moreover, in this embodiment, various combination of catalysts provided herein can be present on an electrode base 5 forming discrete regions or islands.

[0048] In the illustration of FIG. 8A, the face of the catalytic layer is illustrated as being substantially planar. However, the surface area of the catalyst layer can be increased beyond what can be achieved with the planar face. In some instances, increasing the surface area of the catalyst can increase the catalytic current for a given overpotential.Attorney Docket No.00172-003WO1 A variety of methods can be employed to increase the surface area of the catalyst. For instance, the catalytic layer can be porous and / or can be microstructured using techniques such as mesoscale self-assembly, soft lithograph, lithography, anodic etching, or other methods known to the art. In some instances, the catalytic layer is constructed such that the specific surface area of the catalytic layer is much greater than the geometric area of the electrode. This can be expressed as a surface roughness factor (specific surface area / geometric area of the surface area of a planar electrode covered by the catalytic layer). A non-porous catalyst layer with a smooth surface would have a surface roughness factor of 1. The catalytic layer may have surface roughness factors greater than 1, 10, 100 or 1000.

[0049] FIG. 8B presents an example of an electrode comprising a catalytic oxide material and / or catalytic alloy material of the disclosure. The electrode 7 can include one or more of the catalytic oxide materials and / or catalytic alloy materials disclosed herein as catalytic layer 4. For instance, catalytic layer 4 can include, consist of, or consist essentially of one or more components selected from the group consisting of M1xM2yM3zM4tM5uOv,and / or M1xM2yM3zM4tM5uas disclosed herein. Catalytic layer 4 may further comprise fillers, electrically conductive materials, diluents, and / or binders. Electrode 7 can further comprise electrode base 5.

[0050] An electrode that comprises a catalytic mixed metal oxide material of the disclosure can be employed in an electro-oxidation system such as an oxygen evolution system, where the Oxygen Evolution Reaction (OER) is catalyzed at one or more electrodes included in the system.

[0051] FIG. 9A provides a general schematic of an electrode system for oxygen evolution. The system depicted comprises two chambers 15 and 18 separated by a membrane 11. Chambers 15 and 18 can be flow spaces that carry water or vapor, whereinAttorney Docket No.00172-003WO1 chamber 15 comprises water in contact with anode 14 and chamber 18 comprises hydrogen ions and H2in contact with cathode 19. Anode 14 can comprise a substrate or base 5. Suitable materials for substrate or base 5 include, but are not limited to, metals, metal alloys, metal phosphide and metal oxides such as Ni, Cu, Cu / Au, NiPx, CoPx, CoOx, and NiFeOx. When the anode 14 is or includes a photoanode 14, the anode base or substrate 5 can include or consist of a photoanode light absorber selected to absorb light at a wavelength to which the photoanodes 14 will be exposed during operation. As described above, the substrate or base 5 of anode 14 includes a catalytic layer 4 on an electrode base (target surface / substrate) 5. The catalytic layer 4 includes, consists of, or consists essentially of one or more of the catalysts having the general formula M1xM2yM3zM4tM5uOvand / or M1xM2yM3zM4tM5u. The catalytic layer 4 can include components in addition to the one or more catalysts. For instance, the catalytic layer 4 can include one or more components selected from the group consisting of binders, polymers, membranes, electrical conductors, ionic conductors, solid electrolytes, porous materials, and inert support materials. The electrode base 5 represents the portion of the electrode having a traditional electrode construction.

[0052] FIG. 9A also depicts membrane 11. Suitable membranes 11 include, but are not limited to, polyaromatic polymers, fluorinated polymers functionalized with sulfonic acid groups. An example of a suitable fluorinated polymer functionalized with sulfonic acid groups is sold under the trademark NAFION^. A suitable thickness for the membrane 11 includes, but is not limited to, a thickness greater than 1 µm, 5 µm, or 10 µm and / or less than 500 µm, 1000 µm.

[0053] FIG. 9A also depicts an electrical pathway that includes the anode 14, the one or more electrical conductors 34 and the cathode 19. An external bias source 36 positionedAttorney Docket No.00172-003WO1 along the electrical pathway so as to apply a bias between the cathode 19 and the anode 14. Suitable external bias source 36 includes, but is not limited to, batteries, fuel cells, and grid electricity.

[0054] FIG. 9A depicts cathode 19 present in chamber or flow space 18. The cathode 19 can include an optional cathode catalyst layer 24 on a cathode conductor 26. The cathode catalyst layer 24 can include one or more cathode catalysts selected to catalyze the half reaction that occurs at the cathode 19. Although the one or more cathode catalysts are shown as being included in a cathode catalyst layer 24, the one or more cathode catalysts can be included in the cathode conductor 26. Suitable cathode catalysts include, but are not limited to, reduction catalysts. When the half reaction at the cathode 22 is the hydrogen evolution reaction (HER), a suitable cathode catalyst includes, but is not limited to, Pt, Ni, NiPx, CoPx, NiMo, and combinations thereof. When the cathode 19 is not photoactive, suitable cathode conductors 26 include, but are not limited to, metals and metal oxides such as metals, metal alloys, metal phosphide and metal oxides such as Ni, Cu, Cu / Au, NiPx, CoPx, CoOx, NiFeOx. When the cathode 19 is or includes a photocathode 19, the cathode conductor 26 can include a photocathode light absorber selected to absorb light at a wavelength to which the photocathode 22 will be exposed during operation.

[0055] FIG. 9B illustrates and example of a water electrolysis cell 100 capable of carrying out OER. Water electrolysis cell 100 includes an anode layer 12 in contact with a membrane 11. In a particular embodiment, anode layer 12 comprises a catalytic oxide material and / or catalytic alloy material of the disclosure. Anode layer 12 may further comprise fillers, electrically conductive materials, diluents, and / or binders. Although anode layer 12 is shown as a single layer of material, anode layer 12 can include multiple layersAttorney Docket No.00172-003WO1 of material. For instance, anode layer 12 can include one or more layers of catalytic oxide materials and / or catalytic alloy materials of the disclosure deposited or layered on membrane 11. Electrolysis cell 100 further comprises cathode layer 13. In one embodiment, cathode layer 13 comprises a catalytic mixed metal oxide material of the disclosure. In another embodiment, cathode layer 13 may comprise a conductive material and one or more reduction catalysts. Suitable cathode catalyst includes, but are not limited to, Pt, Ni, NiPx, CoPx, NiMo, and combinations thereof. Cathode layer 13 may further comprise fillers, electrically conductive materials, diluents, and / or binders. Although cathode layer 13 is shown as a single layer of material, cathode layer 13 can include multiple layers of material. Separating cathode layer 13 from anode layer 12 is membrane 11. Membrane 11 can comprise an ionomer membrane. Membrane 11 can comprise a single layer or multiple layers of material. Membrane 11 provides an acidic and conductive medium for water splitting reactions. Ionomers are polymers that include electrically neutral repeating units and ionized repeating units. Suitable ionomers include copolymers of a substituted or unsubstituted alkylene and an acid such as sulfonic acid. In one example, the ionomer is a copolymer of tetrafluoroethylene and perfluoro-3,6-dioxa-4-methyl-7-octene- sulfonic acid. A suitable material is sold under the trademark NAFION^. NAFION^ is an example of a material that is cationically conductive of cations but is not conductive of anions or nonionic atoms or nonionic compounds. In a certain embodiment, anode layer 12 and cathode layer 13 are deposited or coated onto the surface of membrane 11 to form a catalyst- coated membrane 10. Electrolysis cell 100 further comprises layers or spaces that are configured to promote the diffusion of gases catalyzed by anode layer 12 and cathode layer 13. In a particular embodiment, anode layer 12 is in contact with anode gas-diffusion layer 20. In a further embodiment, anodeAttorney Docket No.00172-003WO1 gas-diffusion layer 20 is located on the side opposite of anode layer 12 that is in contact with membrane 11. In another embodiment, cathode layer 13 is in contact with cathode gas- diffusion layer 30. In a further embodiment, cathode gas- diffusion layer 30 is located on the side opposite of cathode layer 13 that is in contact with membrane 11. Electrolysis cell 100 further comprises gasket 40 and gasket 50. Gasket 40 and gasket 50 are impermeable to fluids. Gasket 40 and gasket 50 can be made of any solid or sealing material that is impermeable to fluids, including plastic, rubber, silicone, and the like. Specific examples of materials that can be used for gasket 40 and gasket 50 include EPDM, PTFE, low permeation butyl, low permeation FKM, VMQ, or any combination thereof. Gasket 40 and gasket 50 may be of selected of varying hardness from flexible to rigid. Gasket 40 and gasket 50 can have any shape or design, including O-Ring, profiled, spiral wound, etc. Anode separator 60 can comprise fluid channels or flow fields 65. Alternatively, anode separator 60 does not comprise raised fluid channels. Similarly, cathode separator 70 can comprise fluid channels or flow fields 75. Alternatively, cathode separator 70 does not comprise raised fluid channels. In particular embodiment, anode separator 60 and cathode separator 70 are in the form of bipolar plates. Anode separator 60 and cathode separator 70 can be produced using a variety of techniques, including stamping, hydroforming, chemical etching, 3D printing, and presswork tooling. In a particular embodiment, anode separator 60 and cathode separator 70 are produced using a 3D printer or chemical etching. Chemical etching provides for simultaneous removal of metal, allowing for the creation of intricate channels or flow fields on both sides of the plate. Chemical etching also avoids introducing mechanical stress or burring, which can potentially compromise stack bonding and overall performance. This ensures the integrity of the etched plate whileAttorney Docket No.00172-003WO1 maintaining optimal functionality and performance without any detrimental effects. Anode separator 60 and cathode separator 70 are typically made of metal (e.g., stainless steel, titanium, or aluminum) graphite, or carbon black. Anode separator 60 and cathode separator 70 are designed to evenly distribute the fuel and the oxidant to the catalyst-coated membrane. Anode separator 60 and cathode separator 70 also collect the generated electric current at the output terminals (not shown). In a further embodiment, the disclosure provides for a fuel cell or water electrolysis system that comprises a plurality of water electrolysis cell 100. In yet a further embodiment, the disclosure provides for a fuel cell or water electrolysis system that comprises 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 150, 200, 250, 300, 400, 500, 600, 700, 800, 900, 1000 or more, or a range that includes or is between any two of the foregoing numbers, of water electrolysis cell 100. In a particular embodiment, the fuel cell or water electrolysis system comprises a plurality of water electrolysis cell 100 that are physically contacting each other in a stacked manner.

[0056] In the illustration for FIG. 9B, the face of the anode layer 12 and cathode layer 13 are illustrated as being substantially planar. However, the surface area of the anode layer 12 and cathode layer 13 can be increased beyond what can be achieved with the planar face. In some instances, increasing the surface area of anode layer 12 and / or cathode layer 13 can increase the catalytic current for a given overpotential. A variety of methods can be employed to increase the surface area of the anode layer 12 and cathode layer 13. For instance, anode layer 12 and / or cathode layer 13 can be porous and / or can be micro-structured using techniques such as mesoscale self-assembly, soft lithograph, lithography, anodic etching, or other methods known to the art. In some instances, anode layer 12 and / or cathode layer 13 is constructed such that the specific surface area of theAttorney Docket No.00172-003WO1 catalytic layer is much greater than the geometric area or the electrode. This can be expressed as a surface roughness Factor (specific surface area / geometric area or the surface area or a planar electrode covered by the catalytic layer). A non-porous catalyst layer with a smooth surface would have a surface roughness factor of 1. The catalytic mixed metal oxide layer may have surface roughness factors greater than l, 10, 100 or 1000.

[0057] An electro-oxidation system such as an oxygen evolution system can include an anode in contact with an anolyte. One or more different layers of the anode can include, consist essentially of, or consist of one or more of the catalysts. In some instances, the anolyte has a pH less than 15 and greater than -1.

[0058] The disclosure further provides methods for electrolyzing water, comprising: contacting an aqueous medium with an anode and a cathode, wherein the anode comprises a catalytic oxide material disclosed herein; and applying a voltage to provide a current density to cause water in the aqueous medium to be electrochemically split to form oxygen and hydrogen. In a further embodiment, the aqueous medium has a pH of less than 5 and the volage is applied under anodic conditions. In yet a further embodiment, the aqueous medium comprises sulfuric acid.

[0059] In some embodiments, there is provided a water electrolyzer system, comprising: an electrolytic cell configured to receive water; an anode comprising a catalytic oxide material disclosed herein; a cathode; and a voltage source to provide a current density to cause the water to be electrochemically split to form oxygen and hydrogen at the anode and cathode respectively. The water electrolyzer system can include one or more operating features, elements, or conditions and / or includes equipment or features thereof having one or more features, as described or illustrated orAttorney Docket No.00172-003WO1 claimed herein.

[0060] In some embodiments, there is provided a system for CO and / or CO2electroreduction to produce a multi-carbon compound, comprising: an electrolytic cell configured to receive a liquid electrolyte and CO and / or CO2gas; an anode comprising a catalytic oxide material disclosed herein; a cathode comprising a metal-containing electroreduction catalyst; and a voltage source to provide a current density to cause the CO and / or CO2gas contacting the cathode to be electrochemically converted into the multi-carbon compound and to cause an oxygen evolution reaction at the anode. The system can also include one or more operating features, elements, or conditions and / or includes equipment or features thereof having one or more features, as described or illustrated or claimed herein.

[0061] An electro-oxidation system such as an oxygen evolution system can include an anode in contact with an anolyte. One or more different layers of the anode can include, consist essentially of, or consist of one or more of the catalysts. In some instances, the anolyte has a pH less than 15 and greater than -1.

[0062] The disclosure further provides methods for electrolyzing water, comprising: contacting an aqueous medium with an anode and a cathode, wherein the anode comprises a catalytic oxide material and / or catalytic alloy material as disclosed herein; and applying a voltage to provide a current density to cause water in the aqueous solvent to be electrochemically split to form oxygen and hydrogen. In a further embodiment, the aqueous medium has a pH of less than 5 and the volage is applied under anodic conditions. In yet a further embodiment, the aqueous medium comprises sulfuric acid.

[0063] In some embodiments, there is provided a water electrolyzer, comprising: an electrolytic cell configured toAttorney Docket No.00172-003WO1 receive water; an anode comprising a catalytic oxide material and / or catalytic alloy material as disclosed herein; a cathode; and a voltage source to provide a current density to cause the water to be electrochemically split to form oxygen and hydrogen at the anode and cathode respectively. The water electrolyzer can include one or more operating features, elements, or conditions and / or includes equipment or features thereof having one or more features, as described or illustrated or claimed herein.

[0064] In some embodiments, there is provided a system for CO and / or CO2electroreduction to produce a multi-carbon compound, comprising: an electrolytic cell configured to receive a liquid electrolyte and CO and / or CO2gas; an anode comprising a catalytic oxide material and / or catalytic alloy material as disclosed herein; a cathode comprising a copper containing electroreduction catalyst; and a voltage source to provide a current density to cause the CO and / or CO2gas contacting the cathode to be electrochemically converted into the multi-carbon compound and to cause an oxygen evolution reaction at the anode. The system can also include one or more operating features, elements, or conditions and / or includes equipment or features thereof having one or more features, as described or illustrated or claimed herein.

[0065] The catalyst materials were tested for durability by submerging the substrate containing all catalyst compounds in 1M sulfuric acid. The substrate was attached to a potentiostat by titanium clips. This electrochemical cell utilized a Nickel mesh counter electrode for hydrogen evolution and a saturated calomel (SCE) reference electrode. A voltage of 1.5V (vs the SCE) was applied to the substrate (referred to as the 'working electrode') for 4 hours to enable oxygen evolution on the catalyst-containing substrate. The sample was run for 3 hours under these conditions to mimic the conditions in a proton exchange membrane water electrolyzer (PEMWE).Attorney Docket No.00172-003WO1

[0066] It will be understood that various modifications may be made without departing from the spirit and scope of this disclosure. Accordingly, other embodiments are within the scope of the following claims.

Claims

Attorney Docket No.00172-003WO1 WHAT IS CLAIMED IS:

1. A composition comprising: a catalytic oxide material having the atomic formula of M1xM2yM3zM4tM5uOv; and / or a catalytic alloy material having the atomic formula of M1xM2yM3zM4tM5u,wherein, M1, M2, M3, M4 and M5 are different metals, and wherein M1, M2, M3, M4 and M5 are selected from Ru, Ni, W, Nb, Mn, Fe, Ti, Ag, V, Co, and Mo; wherein x+y+z+t+u=1; and wherein the catalytic oxide material and the catalytic alloy material have electrochemical activity in an acidic environment.

2. The composition of claim 1, wherein one of M1, M2, M3, M4 and M5 is Ru or Fe.

3. The composition of claim 1 or claim 2, wherein one of M1, M2, M3, M4 and M5 is W or V.

4. The composition of any one of claims 1 to 3, wherein the composition comprises a catalytic oxide material where the metals making up M1xM2yM3zM4tM5uOvare selected from one of the following: (a) Ru, Ni, W, Nb, and Mn; (b) Ru, Fe, Ti, Ag, and W; (c) Ru, Fe, Ti, Nb, and W; (d) Ru, Ti, V, Co, and W; and (e) Fe, Mn, Mo, W, and Nb.

5. The composition of claim 4, wherein the amount of oxygen in the catalytic oxide material results from annealing theAttorney Docket No.00172-003WO1 catalytic oxide material in air at a temperature from about 500 °C to about 700 °C.

6. The composition of claim 5, where M1xM2yM3zM4tM5uOvis RuxNiyWzNbtMnuOvwhere 0.09≤x≤0.54, 0.12≤y≤0.31, 0.11≤z≤0.26, 0.04≤t≤0.17, 0.16≤u≤0.23 and the oxygen fraction v is the number required in the lattice after annealed at about 700˚C in air.

7. The composition of claim 5, where M1xM2yM3zM4tM5uOvis RuxFeyTizAgtWuOvwhere 00.08≤x≤0.34, 0.03≤y≤0.18, 0.12≤z≤0.77, 0.08≤t≤0.47, 0.02≤u≤0.13 and the oxygen fraction v is the number required in the lattice after annealed at about 500˚C in air.

8. The composition of claim 5, where M1xM2yM3zM4tM5uOvis RuxFeyTizNbtWuOvwhere 0.16≤x≤0.45, 0.03≤y≤0.30, 0.14≤z≤0.29, 0.02≤t≤0.10, 0.09≤u≤0.45 and the oxygen fraction v is the number required in the lattice after annealed at about 600˚C in air.

9. The composition of claim 5, where M1xM2yM3zM4tM5uOvis RuxTiyVzCotWuOvwhere 0.06≤x≤0.26, 0.16≤y≤0.27, 0.14≤z≤0.33, 0.12≤t≤0.28, 0.17≤u≤0.26 and the oxygen fraction v is the number required in the lattice after annealed at about 500˚C in air.

10. The composition of claim 5, where M1xM2yM3zM4tM5uOvis FexMnyMozWtNbuOvwhere 0.20≤x≤0.48, 0.21≤y≤0.40, 0.05≤z≤0.14, 0.12≤t≤0.23, 0.04≤u≤0.14 and the oxygen fraction v is the number required in the lattice after annealed at about 700˚C in air.Attorney Docket No.00172-003WO1 11. The composition of any one of claims 1 to 3, wherein the composition comprises a catalytic alloy material where the metals making up M1xM2yM3zM4tM5uare selected from one of the following: is selected from one the following: (i) Ru, Co, V, W, and Ti; and (ii) Ru, Fe, Co, V, and Ti.

12. The composition of claim 11, wherein the catalytic alloy material is annealed at about 500 °C to about 700 °C in a reducing environment.

13. The composition of claim 12, wherein the reducing environment comprises a mixture of hydrogen and argon gases.

14. The composition of claim 12 or claim 13, where M1xM2yM3zM4tM5uis RuxCoyVzWtTiuwhere 0.08≤x≤0.23, 0.12≤y≤0.27, the catalytic alloy reducing environment.

15. The composition of claim 12 or claim 13, where M1xM2yM3zM4tM5uis RuxFeyCozVtTiuwhere 0.14≤x≤0.26, 0.18≤y≤0.28, the catalytic alloy reducing environment.

16. An electrode comprising the composition of any one of claims 1 to 15.

17. The electrode of claim 16, wherein the electrode is part of an oxygen evolution system, and wherein the electrode catalyzes the oxidation of water to oxygen gas.

18. The electrode of claim 16 or claim 17, wherein the composition functions at the surface of the electrode, defines the surface or the electrode, or interacts with one or moreAttorney Docket No.00172-003WO1 components or the environment in which the electrode is positioned.

19. A method for electrolyzing water, comprising: contacting an aqueous medium with an anode and a cathode, wherein the electrode of any one of claims 16 to 18 is the anode; and applying a voltage to provide a current density to cause water in the aqueous solvent to be electrochemically split to form oxygen and hydrogen.

20. The method of claim 19, wherein the aqueous medium has a pH of less than 5 and the volage is applied under anodic conditions.

21. The method of claim 20, wherein the aqueous medium comprises sulfuric acid.

22. A water electrolysis system that comprises one or more water electrolysis cells, wherein the water electrolysis cell comprises: an ion exchange membrane that a portion of which is coated on one side with one or more anode layers, and coated on the opposite side with one or more cathode layers, wherein anode layer(s) comprise the composition of any one of claims 1 to 15; an anode gas-diffusion layer in fluid contact with the one or more anode layers; a cathode gas-diffusion layer in fluid contact with the one or more cathode layers; a plurality of gaskets that prevent the flow of fluids and ions across the proton exchange membrane which is not coated by the one or more anode layers or the one or more cathode layers; andAttorney Docket No.00172-003WO1 an anode separator and a cathode separator comprising channels for a fluid comprising water, and wherein the anode separator is in fluid contact with the anode gas-diffusion layer, and the cathode separator is in fluid contact with the anode gas-diffusion layer.

23. The water electrolysis system of claim 22, wherein the water electrolysis system comprises at least ten or more water electrolysis cells.

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