▎ 摘　　要

NOVELTY - A catalyst comprises cobalt sulfide/reduced graphene oxide. The cobalt sulfide is deposited on reduced graphene oxide nanosheets. USE - Catalyst used for electrolyzing water to produce hydrogen. ADVANTAGE - The catalyst has high activity for electrolyzing water to produce hydrogen. DETAILED DESCRIPTION - A catalyst comprises cobalt sulfide/reduced graphene oxide. The cobalt sulfide is deposited on reduced graphene oxide nanosheets. The cobalt sulfide/reduced graphene oxide is of formula: Co9S8/rGO. An INDEPENDENT CLAIM is included for preparation of the catalyst, which involves using acetone, tetrakis(thiourea)cobalt(II) nitrate, organic amine and organic phosphorus.