Self-supporting porous Ni-S electrocatalyst with carbon doping for hydrogen evolution reaction

•The Self-supporting porous Ni-S electrocatalysts with carbon doping are electrodeposited by a bubble template method.•Carbon with good electrical conductivity mainly exists in the surface layer.•The porous Ni-S-C films show the highest electrocatalytic activity than that of carbon-free porous films. Hydrogen evolution catalysts with excellent catalytic activity and low cost play an essential role in industrialization of water electrolysis. Ni-S electrocatalysts with carbon doping are promising hydrogen evolution reaction catalysts because of its high catalytic activity. Carbon has good electrical conductivity, and the synergistic effects of carbon and nickel-based catalysts can further improve the electrocatalytic activity. In order to dope carbon, nickel-thiourea complex was synthesized on the surface of electrocatalysts by a bubble template-directed method. The cauliflower-type Ni-S-C films are formed on the surface, which have much better electrocatalytic activity than porous Ni-S and Ni films in 1 M KOH solution. This work demonstrates that the presence of carbon in the surface layer benefits the charge transfer and improves the electrochemical activity.