High performance earth-abundant electrocatalysts for hydrogen evolution reaction and other reactions
Electrodes for catalyzing electrochemical reactions (e.g., the hydrogen evolution reaction) are provided. The electrode may comprise a ternary pyrite-phase transition metal phosphochalcogenide (e.g., CoPS) disposed on a substrate, wherein the ternary pyrite-phase transition metal phosphochalcogenide is a solid material of a ternary compound of a transition metal, phosphorous (P), and a chalcogen, the solid material characterized by a substantially single, ternary alloy phase having a pyrite crystal structure. Methods of using and making the electrodes are also provided.
1. A method for making an electrode, the method comprising exposing a layer of a transition metal-containing precursor disposed on a substrate to a chalcogen-phosphorous atmosphere at an elevated temperature and for a period of time to convert the transition metal-containing precursor to a ternary pyrite-phase transition metal phosphochalcogenide, wherein the ternary pyrite-phase transition metal phosphochalcogenide is a solid material of a ternary compound of a transition metal, phosphorous (P), and a chalcogen, the solid material characterized by a single, ternary alloy phase having a pyrite crystal structure.
2. The method of claim 1 , wherein chemical species at the surface of the solid material are the same as chemical species in the bulk of the solid material.
3. The method of claim 1 , wherein the ternary pyrite-phase transition metal phosphochalcogenide is a ternary pyrite-phase cobalt phosphochalcogenide, a ternary pyrite-phase nickel phosphochalcogenide, or combinations thereof.
4. The method of claim 1 , wherein the ternary pyrite-phase transition metal phosphochalcogenide is ternary pyrite-phase cobalt phosphosulfide, ternary pyrite-phase cobalt phosphoselenide, ternary pyrite-phase nickel phosphosulfide, ternary pyrite-phase nickel phosphoselenide, or combinations thereof.
5. The method of claim 1 , wherein the ternary pyrite-phase transition metal phosphochalcogenide has a formula MPX, wherein M is a transition metal selected from Co, Ni, Fe, and Mn; P is phosphorous; and X is a chalcogen selected from S, Se, and Te.
6. The method of claim 5 , wherein M is a transition metal selected from Co and Ni; P is phosphorous; and X is a chalcogen selected from S and Se.
7. The method of claim 5 , wherein the ternary pyrite-phase transition metal phosphochalcogenide is CoPS, CoPSe, NiPSe, or combinations thereof.
8. The method of claim 1 , wherein the substrate is a carbon substrate, a metal substrate, a glass substrate, or a semiconductor substrate.
9. The method of claim 1 , wherein the transition metal is alloyed with one or more other transition metals such that the ternary pyrite-phase transition metal phosphochalcogenide is an alloyed ternary pyrite-phase transition metal phosphochalcogenide.
10. The method of claim 9 , wherein the alloyed ternary pyrite-phase transition metal phosphochalcogenide has a formula M 1 M 2 PX, wherein M 1 and M 2 are transition metals independently selected from Co, Ni, Fe, and Mn; P is phosphorous; and X is a chalcogen selected from S, Se, and Te.
11. The method of claim 1 , wherein the solid material is in the form of nanowires, nanoplates, or combinations thereof, wherein the nanowires and the nanoplates extend vertically away from the substrate.
12. The method of claim 11 , wherein the nanowires have an average diameter in the range of from 10 nm to 100 nm; and the nanoplates have an average thickness in the range of from 10 nm to 100 nm and an average width in the range of from 100 nm to 1000 nm.
13. The method of claim 1 , wherein the chalcogen-phosphorous atmosphere is formed by thermally evaporating a mixture of phosphorous and chalcogen elemental powders.
14. The method of claim 1 , wherein the elevated temperature is in a range of from 400° C. to 700° C. and the period of time is in a range of from 5 minutes to 2 hours.
15. The method of claim 1 , wherein the layer of the transition-metal containing precursor is a film of a transition metal and the solid material is in the form of nanoparticles.
16. The method of claim 1 , wherein the transition-metal containing precursor is a compound in the form of nanowires, nanoplates, or combinations thereof and the solid material is in the form of nanowires, nanoplates, or combinations thereof.
17. The method of claim 16 , wherein the compound is selected from an oxide, a hydroxide, an oxyhydroxide, a hydroxide carbonate, a fluoride, a chloride, a bromide, and combinations thereof.
18. The method of claim 17 , wherein the compound is the hydroxide, the hydroxide carbonate, or combinations thereof.
19. The method of claim 16 , wherein the transition-metal containing precursor is formed via hydrothermal growth.
20. The method of claim 16 , wherein the ternary pyrite-phase transition metal phosphochalcogenide is CoPS, CoPSe, NiPSe, or combinations thereof.