Nickel-based electrocatalyst for anion exchange membrane water electrolysis

Abstract

Electrocatalysts for anion exchange membrane water electrolysis include nickel and cobalt. In some examples, electrocatalysts can include manganese, can have partial substitution of oxygen by phosphorus, and / or can include molybdenum, cerium and / or yttrium. In some examples, electrocatalysts can have a composition of Ni0.35Co0.65Ox, Ni0.31Co0.69Ox, Ni0.38Co0.62Ox, Ni0.47Co0.53Ox, Ni0.25Co0.57Mn0.17Ox, Ni0.35Co0.65P1.3Ox, Ni0.25Co0.57Mn0.17P1.1Ox, or Ni0.38Co0.36Mo0.09Ce0.1Y0.07Ox. In some examples, electrocatalysts can take the form of a powder or an ink. In some examples, electrocatalysts can be prepared by an oxalic acid precipitation method, a methyl imidazole precipitation method, or a citric acid sol-gel method.

Description

TITLE: NICKEL-BASED ELECTROCATALYST FOR ANION EXCHANGE MEMBRANE WATER ELECTROLYSISCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Application No. 63 / 655,233 filed on June 3, 2024 and U.S. Provisional Application No. 63 / 744,884 filed on January 14, 2025, and the entire contents of each are hereby incorporated herein by reference.FIELD

[0002] The present disclosure relates generally to electrocatalyst materials and electrolysis.BACKGROUND

[0003] The following paragraphs are not an admission that anything discussed in them is prior art or part of the knowledge of persons skilled in the art.

[0004] Anion exchange membrane (AEM) electrolysis is the electrolysis of water using a semipermeable membrane. Like a proton-exchange membrane (PEM), the AEM separates the products, provides electrical insulation between electrodes, and conducts ions. An advantage of AEM water electrolysis is that a noble metal catalyst is not required, but a transition metal catalyst can be used instead.INTRODUCTION

[0005] The following is intended to introduce the reader to the detailed description that follows and not to define or limit the claimed subject matter.

[0006] In an aspect, the present disclosure relates to an electrocatalyst for anion exchange membrane water electrolysis, the electrocatalyst including nickel and cobalt. The electrocatalyst can consist of about 25 to 50 at% nickel and about 35 to 70 at%cobalt. The electrocatalyst can have a composition of Nio.35Coo.65Ox Nio.31Coo.69Ox, Nio.38Coo.62Ox or Nio.47Coo.53Ox.

[0007] In some examples, the electrocatalyst includes manganese. The electrocatalyst can consist of about 0 to 25 at% manganese. The electrocatalyst can have a composition of Nio.25Coo.57M no. i?Ox.

[0008] In some examples, the electrocatalyst has a partial substitution of oxygen by phosphorus. The electrocatalyst can have a composition of Nio.35Coo.65P1.3Ox or Nio.25Coo.57Mno.17P1.1 Ox.

[0009] In some examples, the electrocatalyst includes molybdenum, cerium and / or yttrium. The electrocatalyst can have a composition of Ni0.38Co0.36Mo0.09Ce0.1Y0.07Ox.

[0010] In some examples, the electrocatalyst is in the form of a powder.

[0011] In some examples, the electrocatalyst is in the form of an ink for air or ultrasonic spray coating, screen printing or blade coating, and including an ionomer binder.

[0012] In some examples, an electrode includes the electrocatalyst deposited onto a support, wherein the support is formed of at least one of porous nickel, porous stainless steel, and a membrane.

[0013] In an aspect, the present disclosure relates to a method, including: preparing a first solution including a ligand; preparing a second solution including a metal salt; reacting the first and second solutions; precipitating a metal ligand or forming a gel after partial evaporation of the solution; drying the metal precipitate; and heat treating the metal precipitate or the gel to form a metal oxide.

[0014] In some examples, the ligand consists of oxalic acid, citric acid or methyl imidazolium.

[0015] In some examples, the metal oxide is in the form of a powder.

[0016] In some examples, the method includes partially substituting oxygen of the metal oxide by phosphorus. The method can include providing a source of phosphorus ina furnace, introducing the metal oxide in the furnace, and flowing a gas from the source of phosphorus to the metal oxide.

[0017] In some examples, the method includes adding the metal oxide to a solution including an ionomer binder to form an ink for air or ultrasonic spray coating, screen printing or blade coating.

[0018] In some examples, the method includes air or ultrasonic spray coating, screen printing or blade coating the metal oxide onto a support to form an electrode, wherein the support is formed of at least one of porous nickel, porous stainless steel, and a membrane.

[0019] In some examples, an electrocatalyst prepared according to the method has a composition of Nio.35Coo.65Ox, Nio.31 Coo.69Ox, Nio.38Coo.62Ox, Nio.47Coo.53Ox, Nio.25Coo.57M no. i?Ox, Nio.35Coo.65P1.3Ox, Nio.25Coo.57Mno.17P1.1 Ox, orNi0.38Co0.36Mo0.09Ce0.1Y0.07Ox.

[0020] Other aspects and features of the teachings disclosed herein will become apparent, to those ordinarily skilled in the art, upon review of the following description of the specific examples of the present disclosure.BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The drawings included herewith are for illustrating various examples of apparatuses and methods of the present disclosure and are not intended to limit the scope of what is taught in any way. In the drawings:

[0022] Figure 1 shows preparation of metal oxide.

[0023] Figure 2 shows modification of metal oxide.

[0024] Figures 3 and 4 are micrograph images of a first example catalyst.

[0025] Figure 5 shows testing results for the first example catalyst.

[0026] Figures 6 and 7 are micrograph images of a second example catalyst.

[0027] Figure 8 shows testing results for the second example catalyst.

[0028] Figures 9 and 10 are micrograph images of a third example catalyst.

[0029] Figure 11 shows testing results for the third example catalyst.

[0030] Figure 12 shows testing results for the fourth example catalyst.

[0031] Figure 13 shows testing results for the fifth example catalyst.

[0032] Figure 14 shows testing results for the sixth example catalyst.

[0033] Figure 15 shows testing results for the seventh example catalyst.

[0034] Figure 16 shows testing results for the eighth example catalyst.DETAILED DESCRIPTION

[0035] Various apparatuses or methods will be described below to provide an example of an embodiment of each claimed invention. No embodiment described below limits any claimed invention and any claimed invention may cover apparatuses and methods that differ from those described below. The claimed inventions are not limited to apparatuses and methods having all of the features of any one apparatus or method described below, or to features common to multiple or all of the apparatuses or methods described below. It is possible that an apparatus or method described below is not an embodiment of any claimed invention. Any invention disclosed in an apparatus or method described below that is not claimed in this document may be the subject matter of another protective instrument, for example, a continuing patent application, and the applicant(s), inventor(s) and / or owner(s) do not intend to abandon, disclaim or dedicate to the public any such invention by its disclosure in this document.Catalyst synthesis

[0036] In some examples, non-noble metal oxides are prepared as anode catalytic materials composed of nickel, cobalt and manganese. The metal content can be in the range of about 25 to 50 at% for nickel, about 35 to 70 at% for cobalt and about 0 to 25 at% for manganese.

[0037] In some examples, these catalysts are prepared by an oxalic acid precipitation method. For the synthesis of approximately 10 g of metal nanostructured particles, two solutions can be prepared: a first solution containing 157.5 g of oxalic acid dihydrate in 1250 mL of deionized water (1 mol / L oxalic acid), placed under stirring at a temperature in the range from 20°C to 70°C; and a second solution containing 175 mmol of metal salt in 750 mL of deionized water (0.233 mol / L metal ions), introduced in a separatory funnel placed on top of the oxalic acid solution.

[0038] Referring to Figure 1 , the second solution can be added dropwisely to the oxalic acid solution with the separatory funnel and the mixture can be left to react with stirring for 3 hours at a temperature in the range from 20°C to 70°C.

[0039] After 3 hours, a metal oxalate compound has precipitated and can be filtered and rinsed with deionized water and dried overnight in a desiccator.

[0040] The powder obtained after the drying step can be placed in a ceramic crucible and heat treated at 350°C for 3 hours to convert the metal oxalate into metal oxide.

[0041] In some examples, these catalysts are prepared by a methyl imidazole precipitation method. For the synthesis of approximately 10 g of metal nanostructured particles, two solutions can be prepared: a first solution containing 102.6 g of methyl imidazole in 1250 mL of deionized water (1 mol / L methylimidazole), placed under stirring at a temperature in the range from 20°C to 70°C; and a second solution containing 175 mmol of metal salt in 750 mL of deionized water (0.233 mol / L metal ions), introduced in a separatory funnel placed on top of the methylimidazole solution.

[0042] Referring to Figure 1 , the second solution can be added dropwisely to the methyl imidazole solution with the separatory funnel and the mixture can be left to react with stirring for 3 hours at a temperature in the range from 20°C to 70°C.

[0043] After 3 hours, a metal methylimidazolium compound has precipitated and can be filtered and rinsed with deionized water and dried overnight in a desiccator.

[0044] The powder obtained after the drying step can be placed in a ceramic crucible and heat treated at 650°C for 3 hours to convert the metal methylimidazolium into metal oxide.

[0045] In some examples, these catalysts are prepared by a citric acid sol-gel method. For the synthesis of approximately 10 g of metal nanostructured particles, two solutions can be prepared: a first solution containing 262.7 g of citric acid monohydrate in 1250 mL of deionized water (1 mol / L citric acid), placed under stirring at a temperature in the range from 20°C to 70°C; and a second solution containing 175 mmol of metal salt in 750 mL of deionized water (0.233 mol / L metal ions), introduced in a separatory funnel placed on top of the citric acid solution.

[0046] The second solution can be added dropwisely to the citric acid solution with the separatory funnel and the mixture can be left to evaporate with stirring for 3 to 6 hours at a temperature in the range from 70°C to 95°C to form a gel.

[0047] After 3 to 6 hours of partial evaporation, a metal citrate gel has formed.

[0048] The gel obtained can be placed in a ceramic crucible and heat treated at350°C to 650°C for 3 hours to convert the metal citrate gel into metal oxide.Modification of metal oxide

[0049] In some examples, metal oxides can undergo partial substitution of oxygen atoms by phosphorus atoms. The source of phosphorus can be sodium hypophosphite.

[0050] Referring to Figure 2, the sodium hypophosphite monohydrate (NaFhPC H2O) powder can be placed in a ceramic combustion boat and introduced in a tube furnace. The metal oxide or hydroxide powder can also be placed in the ceramic combustion boat, and introduced in the tube furnace.

[0051] In some examples, the NaH2PO2 H2O I metal oxide molar ratio is set to at least 2.5, which corresponds to at least 3.5 g of sodium hypophosphite monohydrate for 1 g of metal oxide.

[0052] In some examples, the tube furnace is flushed with nitrogen gas with the sodium hypophosphite monohydrate placed upstream and the metal oxide placed downstream in the tube furnace.

[0053] A fresh filter composed of copper oxide on activated carbon pellets can be used as a phosphine removal trap. The pellets can be placed in a gas wash bottle connected to the outlet of the tube furnace, such as the gas exiting the tube furnace will be passed through this filter.

[0054] In some examples, the tube furnace is purged under N2 for 30 min, then the furnace is heated up to 330°C under N2 with a moderate flow rate (100 mL / min) with a heating ramp of 10°C / min. The temperature can be maintained at 330°C for 1 hour with under N2 at 100 mL / min. At the end of this step, the heating can be turned off while the atmosphere in the tube is maintained under pure N2 for the entire cooling process.

[0055] After the furnace is cooled down to ambient temperature, the tube can be opened and the metal oxide / phosphide powder can be taken out of the tube and used as modified metal oxide catalyst. The oxygen substitution by phosphorus atoms can be typically in the range from about 40% to 60%.Ink preparation

[0056] In some examples, ink preparation starts by weighing a desired mass of catalytic powder for the target catalyst weight loading on the electrode, the surface of the electrode to coat, and the spray coating efficiency. Typically, for metal loading of 2 mg / cm2, for each 5 cm2of electrode to be coated, 15 mg of metal oxide can be introduced into 1 .5 mL of the acetone / isopropanol / water mixture. The ink can contain up 0 to 15% of acetone, 20 to 80% of isopropanol and 20 to 80% of water.

[0057] An ionomer binder can then be added to the solution to reach 10 to 20 wt% of the metal oxide mass. The ink can then be sonicated for 10 minutes and stirred for 1 hour before spray coating.Spray coating

[0058] In some examples, spray coating is performed with an X,Y,Z table equipped with a heated support plate and an air spray gun. Generally, a 3 L / min airflow can be used with the airgun equipped with a 0.3 mm nozzle for an efficient flow.

[0059] The support coated can be a porous nickel or stainless steel material for CCS (catalyst coated support) configuration, or a membrane for a CCM (catalyst coated membrane) configuration. The support can be placed on a heated plate with a temperature set between 30°C and 90°C.

[0060] In some examples, the coating is realized by scanning the spray nozzle in X and Y axes to cover homogeneously the support, while the Z axis (height of the spray gun) can remain constant at 9 cm.

[0061] After coating, the electrode can be dried under air in a desiccator. The deposited mass of catalyst can be measured by weighing the porous support or the membrane before the coating (after treatment and drying steps) and after coating and drying steps.

[0062] The following examples of the present disclosure are intended to be illustrative but non-limiting.Example 1 : Nio.33Coo.67Ox anode catalyst

[0063] A first exemplary catalyst was synthesized with 16.476 g of nickel nitrate hexahydrate with 32.963 g of cobalt nitrate hexahydrate in 750 mL of deionized water. The resulting solution was introduced dropwisely into an oxalic acid solution at 70°C containing 157.5 g of oxalic acid in 1250 mL of deionized water.

[0064] The resulting solution is then stirred at 70°C for 3 hours and the precipitate formed is filtered, rinsed with deionized water, dried and heat treated at 350°C for 3 hours.

[0065] Referring to Figures 3 and 4, the resulting powder presented a surface area of 35 m2 / g (BET measurement), a particle size from 10 to 20 nm (TEM) and the final composition determined by ICP-OES is Nio.35Coo.65Ox.

[0066] The catalytic powder is introduced in a water / isopropanol 80 / 20 (v / v) with 18 wt% ionomer binder and coated on a 5 x 5 cm2nickel sintered felt. For the spray coating, the heated plate temperature was set at 40°C.

[0067] A 5 cm2square shaped electrode was cut and assembled in a MEA (membrane electrode assembly) composed of the non-noble metal oxide anode and a Pt / C deposited on Toray 090 carbon paper cathode separated by an Ionomer AF3 membrane. The resulting Pt loading on the electrode was 0.3 mg / cm2

[0068] Referring to Figure 5, the performance of the MEA was measured in a 5 cm2channel flow cell, at 80°C with a 1 M KOH electrolyte circulating in the cell.Example 2: Nio.5Coo.5Ox anode catalyst

[0069] A second exemplary catalyst was synthesized with 24.728 g of nickel nitrate hexahydrate with 24.736 g of cobalt nitrate hexahydrate in 750 mL of deionized water. The resulting solution was introduced dropwisely into an oxalic acid solution at 20°C containing 157.5 g of oxalic acid in 1250 mL of deionized water.

[0070] The resulting solution is then stirred at 20°C for 3 hours and the precipitate formed is filtered, rinsed with deionized water, dried and heat treated at 350°C for 3 hours.

[0071] Referring to Figures 6 and 7, the resulting powder presented a surface area of 50 m2 / g (BET measurement), a particle size from 4 to 10 nm (TEM) and the final composition determined by ICP-OES is Nio.47Coo.53Ox.

[0072] The catalytic powder is introduced in a water / isopropanol 80 / 20 (v / v) with 15 wt% ionomer binder and coated on a 5 x 5 cm2nickel sintered felt. For the spray coating, the heated plate temperature was set at 50°C.

[0073] A 5 cm2square shaped electrode was cut and assembled in a MEA (membrane electrode assembly) composed of the non-noble metal oxide anode and a Pt / C deposited on Toray 090 carbon paper cathode separated by an Ionomer AF3 membrane. The resulting Pt loading on the electrode was 0.3 mg / cm2.

[0074] Referring to Figure 8, the performance of the MEA was measured in a 5 cm2channel flow cell, at 80°C with a 1 M KOH electrolyte circulating in the cell.Example 3: Nio.2sCoo.55Mno.17Ox anode catalyst

[0075] A third exemplary catalyst was synthesized with 13.997 g of nickel nitrate hexahydrate with 27.504 g of cobalt nitrate hexahydrate and 7.336 g of manganese nitrate tetrahydrate in 750 mL of deionized water. The resulting solution was introduced dropwisely into an oxalic acid solution at 20°C containing 157.5 g of oxalic acid in 1250 mL of deionized water.

[0076] The resulting solution is then stirred at 20°C for 3 hours and the precipitate formed is filtered, rinsed with deionized water, dried and heat treated at 350°C for 3 hours.

[0077] Referring to Figures 9 and 10, the resulting powder presented a surface area of 100 m2 / g (BET measurement), a particle size from 4 to 10 nm (TEM) and the final composition determined by ICP-OES is Nio.25Coo.57M no. i?Ox.

[0078] The catalytic powder is introduced in a water / isopropanol 80 / 20 (v / v) with 18 wt% ionomer binder and coated on a 5 x 5 cm2nickel sintered felt. For the spray coating, the heated plate temperature was set at 50°C.

[0079] A 5 cm2square shaped electrode was cut and assembled in a MEA (membrane electrode assembly) composed of the non-noble metal oxide anode and a Pt / C deposited on Toray 090 carbon paper cathode separated by an Ionomer AF3 membrane. The resulting Pt loading on the electrode was 0.3 mg / cm2

[0080] Referring to Figure 11 , the performance of the MEA was measured in a 5 cm2channel flow cell, at 80°C with a 1 M KOH electrolyte circulating in the cell.Example 4: Nio.33Coo.67P1.3Ox anode catalyst

[0081] The metal oxide anode prepared in example 1 was treated for phosphorus atom substitution: 1 g of Nio.33Coo.67Ox were treated at 330°C under nitrogen flow in presence of 3.5 g of sodium hypophosphite monohydrate. The resulting powder composition was Nio.35Coo.65P1.3Ox (ICP-OES). The surface area was 20 m2 / g (BET).

[0082] The catalytic powder is introduced in a water / isopropanol 80 / 20 (v / v) with 18 wt% ionomer binder and coated on a 5 x 5 cm2nickel sintered felt. For the spray coating, the heated plate temperature was set at 50°C.

[0083] A 5 cm2square shaped electrode was cut and assembled in a MEA (membrane electrode assembly) composed of the non-noble modified metal oxide anode and a Pt / C deposited on Toray 090 carbon paper cathode separated by an Ionomer AF3 membrane. The resulting Pt loading on the electrode was 0.3 mg / cm2

[0084] Referring to Figure 12, the performance of the MEA was measured in a 5 cm2channel flow cell, at 80°C with a 1 M KOH electrolyte circulating in the cell.Example 5: Nio.28Coo.55Mno.17P1.1Ox anode catalyst

[0085] The metal oxide anode prepared in example 3 was treated for phosphorus atom substitution: 1 g of Nio.33Coo.67Ox were treated at 330°C under nitrogen flow in presence of 3.5 g of sodium hypophosphite monohydrate. The resulting powder composition was Nio.25Coo.57Mno.17P1.1Ox (ICP-OES). The surface area was 25 m2 / g (BET).

[0086] The catalytic powder is introduced in a water / isopropanol 80 / 20 (v / v) with 18 wt% ionomer binder and coated on a 5 x 5 cm2nickel sintered felt. For the spray coating, the heated plate temperature was set at 50°C.

[0087] A 5 cm2square shaped electrode was cut and assembled in a MEA (membrane electrode assembly) composed of the non-noble metal oxide anode and a Pt / C deposited on Toray 090 carbon paper cathode separated by an Ionomer AF3 membrane. The resulting Pt loading on the electrode was 0.3 mg / cm2.

[0088] Referring to Figure 13, the performance of the MEA was measured in a 5 cm2channel flow cell, at 80°C with a 1 M KOH electrolyte circulating in the cell.Example 6: Nio.33Coo.67Ox anode catalyst

[0089] A sixth exemplary catalyst was synthesized with 16.476 g of nickel nitrate hexahydrate with 32.963 g of cobalt nitrate hexahydrate in 750 mL of deionized water.The resulting solution was introduced dropwisely into an oxalic acid solution at 70°C containing 102.6 g of methylimidazole in 1250 mL of deionized water.

[0090] The resulting solution is then stirred at 20°C for 3 hours and the precipitate formed is filtered, rinsed with deionized water, dried and heat treated at 650°C for 3 hours.

[0091] The resulting powder presented a surface area of 25 m2 / g (BET measurement), and the final composition determined by ICP-OES is Nio.31Coo.69Ox.

[0092] The catalytic powder is introduced in a water / isopropanol 80 / 20 (v / v) with 18 wt% ionomer binder and coated on a 5 x 5 cm2nickel sintered felt. For the spray coating, the heated plate temperature was set at 50°C.

[0093] A 5 cm2square shaped electrode was cut and assembled in a MEA (membrane electrode assembly) composed of the non-noble metal oxide anode and a Pt / C deposited on Toray 090 carbon paper cathode separated by an Ionomer AF3 membrane. The resulting Pt loading on the electrode was 0.3 mg / cm2

[0094] Referring to Figure 14, the performance of the MEA was measured in a 5 cm2channel flow cell, at 80°C with a 1 M KOH electrolyte circulating in the cell.Example 7: Nio.33Coo.67Ox anode catalyst

[0095] A seventh exemplary catalyst was synthesized with 16.476 g of nickel nitrate hexahydrate with 32.963 g of cobalt nitrate hexahydrate in 750 mL of deionized water. The resulting solution was introduced dropwisely into a citric acid solution at 65°C containing 262.7 g of citric acid in 1250 mL of deionized water.

[0096] The resulting solution is then stirred at 85°C for 5 hours and the formed gel is heat treated at 650°C for 3 hours.

[0097] The resulting powder presented a surface area of 235 m2 / g (BET measurement), and the final composition determined by ICP-OES is Nio.38Coo.62Ox.

[0098] The catalytic powder is introduced in a water / isopropanol 80 / 20 (v / v) with 18 wt% ionomer binder and coated on a 5 x 5 cm2nickel sintered felt. For the spray coating, the heated plate temperature was set at 50°C.

[0099] A 5 cm2square shaped electrode was cut and assembled in a MEA (membrane electrode assembly) composed of the non-noble metal oxide anode and a Pt / C deposited on Toray 090 carbon paper cathode separated by an Ionomer AF3 membrane. The resulting Pt loading on the electrode was 0.3 mg / cm2

[0100] Referring to Figure 15, the performance of the MEA was measured in a 5 cm2channel flow cell, at 80°C with a 1 M KOH electrolyte circulating in the cell.Example 8: Nio.35Coo.35Moo.1Ceo.1Yo.1Ox high entropy anode catalyst

[0101] An eighth exemplary catalyst was synthesized with 17.818 g of nickel nitrate hexahydrate with 17.832 g of cobalt nitrate hexahydrate, 2.847 g of ammonium molybdate tetrahydrate, 7.002 g of cerium(lll) nitrate hexahydrate and 6.176 g of yttrium(lll) nitrate hexahydrate in 750 mL of deionized water. The resulting solution was introduced dropwisely into a citric acid solution at 65°C containing 262.7 g of citric acid in 1250 mL of deionized water.

[0102] The resulting solution is then stirred at 85°C for 5 hours and the formed gel is heat treated at 650°C for 3 hours.

[0103] The resulting powder presented a surface area of 32 m2 / g (BET measurement), and the final composition determined by ICP-OES is Ni0.38Co0.36Mo0.09Ce0.1Y0.07Ox.

[0104] The catalytic powder is introduced in a water / isopropanol 80 / 20 (v / v) with 18 wt% ionomer binder and coated on a 5 x 5 cm2nickel sintered felt. For the spray coating, the heated plate temperature was set at 50°C.

[0105] A 5 cm2square shaped electrode was cut and assembled in a MEA (membrane electrode assembly) composed of the non-noble metal oxide anode and a Pt / C deposited on Toray 090 carbon paper cathode separated by an Ionomer AF3 membrane. The resulting Pt loading on the electrode was 0.3 mg / cm2.

[0106] Referring to Figure 16, the performance of the MEA was measured in a 5 cm2channel flow cell, at 80°C with a 1 M KOH electrolyte circulating in the cell.

[0107] While the above description provides examples of one or more apparatuses or methods, it will be appreciated that other apparatuses or methods may be within the scope of the accompanying claims.

Claims

CLAIMSWe claim:

1. An electrocatalyst for anion exchange membrane water electrolysis, the electrocatalyst comprising nickel and cobalt.

2. The electrocatalyst of claim 1 , consisting of about 25 to 50 at% nickel and about 35 to 70 at% cobalt.

3. The electrocatalyst of claim 1 or 2, having a composition of Nio.35Coo.65Ox, Nio.31 Coo.69Ox, Nio.38Coo.62Ox or Nio.47Coo.53Ox.

4. The electrocatalyst of claim 1 or 2, comprising manganese.

5. The electrocatalyst of claim 4, consisting of about 0 to 25 at% manganese.

6. The electrocatalyst of claim 4 or 5, having a composition of Nio.25Coo.57Mno.17Ox.

7. The electrocatalyst of any one of claims 1 to 6, wherein there is partial substitution of oxygen by phosphorus.

8. The electrocatalyst of claim 7, having a composition of Nio.35Coo.65P1.3Ox or Nio.25Coo.57Mno.17P1 .1 Ox.

9. The electrocatalyst of claim 1 or 2, comprising molybdenum, cerium and / or yttrium.

10. The electrocatalyst of claim 9, having a composition ofNi0.38Co0.36Mo0.09Ce0.1Y0.07Ox.11 . The electrocatalyst of any one of claims 1 to 10, in the form of a powder.

12. The electrocatalyst of any one of claims 1 to 10, in the form of an ink for air or ultrasonic spray coating, screen printing or blade coating, and comprising an ionomer binder.

13. An electrode comprising the electrocatalyst of any one of claims 1 to 10 deposited onto a support, wherein the support is formed of at least one of porous nickel, porous stainless steel, and a membrane.

14. A method, comprising: preparing a first solution comprising a ligand; preparing a second solution comprising a metal salt; reacting the first and second solutions; precipitating a metal ligand or forming a gel after partial evaporation of the solution; drying the metal precipitate; and heat treating the metal precipitate or the gel to form a metal oxide.

15. The method of claim 14, the ligand consists of oxalic acid, citric acid or methyl imidazolium.

16. The method of claim 14 or 15, wherein the metal oxide is in the form of a powder.

17. The method of any one of claims 14 to 16, comprising partially substituting oxygen of the metal oxide by phosphorus.

18. The method of claim 17, comprising providing a source of phosphorus in a furnace, introducing the metal oxide in the furnace, and flowing a gas from the source of phosphorus to the metal oxide.

19. The method of any one of claims 14 to 18, comprising adding the metal oxide to a solution comprising an ionomer binder to form an ink for air or ultrasonic spray coating, screen printing or blade coating.

20. The method of any one of claims 14 to 19, comprising air or ultrasonic spray coating, screen printing or blade coating the metal oxide onto a support to form an electrode, wherein the support is formed of at least one of porous nickel, porous stainless steel, and a membrane.21 . An electrocatalyst prepared according to the method of any one of claims 14 to 20, wherein the electrocatalyst has a composition of Nio.35Coo.65Ox, Nio.31Coo.69Ox, Nio.38Coo.62Ox, Nio.47Coo.53Ox, Nio.25Coo.57M no. i?Ox, Nio.35Coo.65P1.3Ox,Nio.25Coo.57Mno.17P1.1Ox, or Ni0.38Co0.36Mo0.09Ce0.1Y0.07Ox.

22. An apparatus and / or a method comprising any combination of one or more of the features described above and / or illustrated in the drawings.

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