Design and in-situ synthesis of unique catalyst via embedding graphene oxide shell membrane in NiS2 for efficient hydrogen evolution

Abstract

Exploring novel tactic to synthesize transition-metal-based electrocatalysts with high activity is crucial to renewable gaseous fuel production. Herein, a simple and efficient synthesis strategy has been successfully developed to in-situ synthesize unique catalysts via embed a graphene oxide (GO) shell membrane in the core of NiS2 employing an ionic liquid-like NiCl2-malonic acid (IL Ni-MA). The elaborately designed IL Ni-MA liquid favors the in-situ growth of breathing GO shell membrane on the surface of NiS2 along with the formation of gas channel. The moderate breathing GO shell membrane and tightly coupled interface gain the optimum electrocatalysis hydrogen evolution and oxygen evolution performance in 1.0 M KOH. It just demands 57 and 294 mV to achieve a current density of 10 mA cm−2 toward HER and OER, respectively. Moreover, the optimum NiS2@GO catalysts can be applied for superior bifunctional catalyst for overall splitting of H2O. A cell voltage of 1.52 V and a stable operation for more than 48 h can be gained. The synthetic route may find application in the surface/interfaces engineering of other embedded catalysts toward new energy and environment applications.