Facile formation of highly active and stable hydrogen evolution catalysts
A method of forming a cathode for hydrogen evolution reaction includes: (1) providing a substrate; (2) forming a precursor layer covering the substrate; and (3) annealing the precursor layer to form an electrocatalyst layer covering the substrate.
1. A method of forming a cathode for hydrogen evolution reaction, the method comprising:
loading a substrate with carbon nanotubes or nanostructures comprising a metal;
forming a precursor layer covering the substrate by electrodepositing the precursor layer onto the substrate from a precursor solution comprising a salt of a first metal and a salt of a second metal, wherein the first metal and the second metal are different transition metals; and
annealing the precursor layer to form an electrocatalyst layer covering the substrate, wherein a combined time to perform the loading, the electrodepositing, and the annealing is about 5-6 hours.
2. The method of claim 1 , wherein the substrate is a metallic foam, foil, or mesh.
3. The method of claim 1 , wherein the first metal is nickel, and the second metal is chromium.
4. The method of claim 1 , wherein the electrocatalyst layer comprises nickel, nickel oxide, and chromium oxide.
5. The method of claim 1 , wherein the precursor solution comprises a salt of a third metal, and the third metal is cobalt, iron, manganese, molybdenum, or tungsten.
6. The method of claim 1 , wherein a molar ratio of the first metal to the second metal in the precursor solution is greater than 1:1.
7. The method of claim 1 , wherein the precursor layer comprises a mixed metal hydroxide comprising the first metal and the second metal.
8. The method of claim 1 , wherein the precursor layer comprises a mixed metal-layered double hydroxide comprising the first metal and the second metal.
9. The method of claim 1 , wherein annealing the precursor layer includes heating to a temperature in a range of 200° C. to 400° C.
10. The method of claim 9 , wherein annealing the precursor layer is performed in vacuum under a flow of an inert gas.
11. The method of claim 9 , wherein annealing the precursor layer is performed in vacuum under a flow of an inert gas and a flow of a reducing gas.
12. The method of claim 1 , wherein the electrocatalyst layer comprises a mixed Ni—NiO—Cr 2 O 3 structure.
13. The method of claim 1 , wherein the carbon nanotubes are multi-walled carbon nanotubes (MWCNTs).
14. The method of claim 1 , wherein a molar ratio of the first metal to the second metal in the precursor solution is about 5:1 or greater.
15. A method of forming a cathode for hydrogen evolution reaction, the method comprising:
loading a substrate with carbon nanotubes or nanostructures comprising a metal;
forming a precursor layer covering the substrate by electrodepositing the precursor layer onto the substrate from a precursor solution comprising a salt of a first metal and a salt of a second metal, wherein the first metal and the second metal are different transition metals; and
annealing the precursor layer to form an electrocatalyst layer covering the substrate,
wherein the electrodepositing is performed for about 2 hours.