Rod-like nickel doped Co3Se4/reduced graphene oxide hybrids as efficient electrocatalysts for oxygen evolution reactions.

In the oxygen evolution reaction (OER), highly active catalysts are essential for reducing the overpotential and improving the slow kinetics of the process. Cobalt selenide (Co3Se4) has always been considered as a promising electrocatalyst for the OER due to the well-suited electronic configuration of the Co ions in it. However, poor exposure of the active sites and low electron conductivity are still its biggest problems. In this study, we report an efficient Ni-doped rod-like Co3Se4 hybridized with reduced graphene oxide (Ni-Co3Se4/rGO) as an OER electrocatalyst. The Ni doping regulates the electronic structure of Co3Se4 and significantly reduces the overpotential of Co3Se4 toward the OER under alkaline conditions. Simultaneously, hybridization of the reduced graphene oxide (rGO) enhances the conductivity which leads to the improvement in OER activity. The Ni-Co3Se4/rGO catalyst shows a lower overpotential (284 mV at 10 mA cm-2) as well as a Tafel slope (71 mV dec-1), which outperformed the benchmark of commercial RuO2. Moreover, Ni-Co3Se4/rGO also shows high stability and long-term durability.