Controlled synthesis of NiFeCr-S/Ni3S2 as efficient hydrogen evolution catalyst for seawater splitting and urea splitting

Hydrogen production by seawater splitting is an environmentally friendly and economical way of hydrogen production, which is very promising. However, slow hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) kinetics limit its development, so efficient and stable catalysts are needed to speed up the reaction process. In this paper, a polymetallic sulfide catalyst NiFeCr-S/Ni3S2 was firstly constructed by hydrothermal and vapor deposition approach on nickel foam. NiFeCr-S/Ni3S2 has well HER catalytic performance in both seawater and urea electrolyte, and the overpotential in alkaline seawater and urea is 236 and 264 mV when the current density is 100 mA cm−2. And we found that this catalyst is also excellent by comparing with the catalysts reported recently. In addition, the catalyst showed strong stability in the 15 h stability test. Density functional theory presents that this Ni3S2 electrode presents the optimal Gibbs free energy of hydrogen adsorption, and this Fe4Ni5S8 electrode presents good metal properties, so the synergistic effect of the two promotes the catalytic performance of the NiFeCr-S/Ni3S2 electrode. This work provides new insights into the effects of different electrolytes on catalytic activity.