Controllable preparation of Cu2S@Ni3S2 grown on nickel foam as efficient seawater splitting electrocatalyst

Abstract

Seawater is one of the richest hydrogen sources around our environment, so it has a lot of advantages to decompose and produce hydrogen. However, considering that chloride ions in seawater have a strong corrosive action on the electrode. Therefore, the design and exploration of highly effective and antiseptic oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) electrocatalysts were studied. It's worth noting that Cu2S@Ni3S2/NF is engaged as a difunctional electrode in this study, which drives a current density of 10 mA cm−2 with requiring overpotentials of only 78 mV and 170 mV, and highlights its significant selectivity of OER and HER. The results show that the increased activity of Cu2S@Ni3S2/NF electrode can be assigned to the synergistic catalysis of (211) and (110) crystal faces, as well as the transfer and the increase of the number of active sites caused by lattice defects. The results of density functional theory show that Cu2S material has optimal free energy of the adsorbed states for H, indicating that the introduction of Cu2S promotes the kinetics of the reaction. The introduction of Ni3S2 material greatly improves the conductivity of Cu2S@Ni3S2/NF electrode. This paper proposes novel insights into the exploration of environmentally friendly and corrosion resistant difunctional catalysts for seawater splitting.