Preparation of graphene-supported S-doped cobalt molybdate composite towards efficient electrochemical oxygen evolution reaction

Abstract

In this paper, graphene-supported S-doped cobalt molybdate composite (S-CoMoO4/GR) was prepared by a simple in situ hydrothermal method. X-ray diffractometer (XRD) was employed to determine the component, which verified that S was doped in the CoMoO4. X-ray photoelectron spectroscopy (XPS), N2 adsorption-desorption analysis and scanning electron microscopy (SEM) was used to observe the surface valence state, microstructure and the morphology of the composite, which demonstrated that S-CoMoO4 was dispersed on the carrier of GR with small plate morphology. Then, the composite was applied on the surface of glassy carbon electrode with oxygen evolution reaction (OER) performance investigated by different electrochemical technologies including linear sweep voltammetry, cyclic voltammetry, electrochemical impedance spectroscopy and i-t tests. The results demonstrate that the prepared catalyst needs an overpotential of 354 mV to achieve the current density of 10 mA cm−2 (η10) and presents good long-term stability with a negligible current decrease in 30 h i-t test, verifying its good OER performance.