Interface engineering of heterostructrured MoSe2/Co0.85Se nanoplate array as a highly efficient electrocatalyst for overall water splitting

Abstract

Hollow nanoplate array of MoSe2/Co0.85Se heterostructure on nickel frame (MoSe2/Co0.85Se/NF) was prepared using metal-organic framework as a template via a process of dissolution–regrowth following by gas-phase selenization and annealing. 3D architecture of MoSe2/Co0.85Se heterostructure shows a significantly enhanced activity and durability as a bifunctional electrocatalyst for oxygen and hydrogen evolution reactions (OER and HER) in alkaline solution. A current density of 10 mA/cm2 can be delivered at an overpotential of 102 mV for HER and 229 mV for OER with a corresponding Tafel slope of only 35 mV/dec for HER and 48 mV/dec for OER, respectively. Density functional theory calculations revealed that MoSe2/Co0.85Se heterostructure will favor water dissociation, and the neutral adsorption energy of H∗ intermediate in MoSe2/Co0.85Se heterostructure can boost hydrogen evolution. OER measurements will cause surface reconstruction of MoSe2/Co0.85Se/NF and form a new heterostructure of CoO/Co2Mo3O8 in alkaline media. OER occurs at Co atoms on CoO/Co2Mo3O8 heterojunction interface, and the neighboring Mo atom will promote the formation of OOH∗ intermediate, leading to a fast OER kinetics. The superior HER and OER performance of MoSe2/Co0.85Se/NF can rival most of reported transition metal catalysts, holding great promise as advanced catalysts for water splitting in industrial scale.