Synthesis of flower-like molybdenum sulfide/graphene hybrid as an efficient oxygen reduction electrocatalyst for anion exchange membrane fuel cells

Abstract

Abstract Nanostructured transition metal chalcogenides (TMCs) have significant interest towards electrochemical devices such as fuel cells, metal-ion batteries, due to their unique physical and electrochemical properties. Herein, we report a facile hydrothermal synthesis of flower-like nanostructured molybdenum sulphide and its incorporation on to graphene as a potential oxygen reduction reaction catalyst in alkaline medium. The phase purity and morphological evolution of MoS 2 is systematically studied through X-ray diffraction and scanning electron microscopic techniques. The electronic states of metal and non-metallic species are deeply studied by X-ray photoelectron spectroscopy. The effect of annealing temperatures and TMC concentrations are also investigated by electrochemical techniques such as cyclic and linear sweep voltammograms. The optimised electrocatalyst (MoS 2 /G-500) delivers significant ORR activity with onset and half-wave potentials of 0.91 and 0.80 V (vs. RHE), respectively. Superior durability compared to state-of-art Pt/C catalyst is ascertained by repeating potential cycles for about 5000 times and also by chronoamperometric technique. Finally, the hybrid catalyst is evaluated in AEMFC as cathode catalyst which delivers peak power density of about 29 mW cm −2 under ambient temperature and pressure. The present findings emphasis that MoS 2 /G catalyst is promising as cost-effective and alternative to noble metal-based catalysts for fuel cell applications.