Ni3S2/Co9S8 directly grown on nickel foam as an environmentally friendly electrocatalyst for seawater splitting

Abstract

Seawater is one of the most abundant sources of hydrogen on Earth, so its decomposition for producing hydrogen has a significant advantage. However, because of the presence of high concentration of chloride ion (Cl−) in seawater, it has corrosive effect on the catalyst. Therefore, the exploration and construction of highly robust anticorrosive OER electrocatalyst were studied. Furthermore, this work describes Co9S8@Ni3S2/NF as a catalyst, which provides a current density of 100 mA cm−2 with a required overpotential of only 154 mV, with emphasis on their remarkable OER selectivity. The experimental analysis demonstrate that the promotion of Co9S8@Ni3S2/NF catalyst activity can be attributed to the construction of heterogeneous interface, the rapid transfer of charge and the exposure of more reaction centers. Density functional theory analysis demonstrates that the Co9S8 material presents greater water adsorption energy, indicating that water preferentially adsorbs on its surface. The introduction of the Ni3S2 electrode greatly promotes the synergistic effect of the Co9S8@Ni3S2/NF electrode. It is the synergistic catalysis of these two electrodes that enhances the catalytic activity and selectivity of the materials. The work furnishes a novel idea for the exploration of efficient, environmentally friendly and highly selective electrodes for seawater splitting.