Nanoporous Cobalt-Selenide as High-Performance Bifunctional Electrocatalyst towards Oxygen Evolution and Hydrazine Oxidation

Abstract

Water splitting is inhibited by the sluggish kinetics of oxygen evolution reaction (OER), which can lead to a high overpotential for overall water electrolysis. Nevertheless, it is an effective strategy to explore high efficient OER electrocatalyst and replace OER with hydrazine oxidation reaction (HzOR) of low theoretical potential. Herein, we report a bifunctional CoSe-3 catalyst with nanoporous structure via one-step electrodeposition. In comparison with CoSe-2 and CoSe-4, CoSe-3 catalyst shows outstanding catalytic performance and stability towards OER with a low overpotenial of 254 mV vs RHE to achieve 10 mA cm−2 and a high durability (16 h at 100 mA cm−2). CoSe-3 further shows excellent performance towards HzOR with an enomous current density of 278 mA cm−2 at 0.4 V vs RHE and a high stability (24 h at 200 mA cm−2). Specially, the mechanism reason of the remarkably enhanced catalytic performance of bifunctional CoSe-3 electrocatalyst was revealed. This can be associated with its uniformly distributed nanoporous structure, high conductivity induced by the excess of Se content, large ECSA and its superaerophobic surface caused by nanoporous structure of CoSe-3.