▎ 摘　　要

NOVELTY - Nickel sulfide nanocrystal catalyst for electrochemical and photoelectrochemical hydrogen production represented by (I). USE - Used as a nickel sulfide nanocrystal catalyst for electrochemical and photoelectrochemical hydrogen production. ADVANTAGE - The method is simple. The catalyst: has high stability and excellent catalytic activity; and reduces hydrogen production process cost. DETAILED DESCRIPTION - Nickel sulfide nanocrystal catalyst for electrochemical and photoelectrochemical hydrogen production represented by NiSx (I). x = 1-1.97 INDEPENDENT CLAIMS are also included for: (1) preparing nickel sulfide nanocrystal catalyst comprising depositing sulfur powder on nickel nanoparticles at temperature of 400-600 degrees C; (2) nickel sulfide nanocrystal catalyst structure formed on the substrate; and (3) preparing catalyst structure comprising (A) coating the substrate with a nickel precursor solution, and (B) depositing sulfur powder on the nickel-coated substrate at temperature of 400-600 degrees C.