Heterostructure and phase engineering synergistically activated highly efficient alkaline hydrogen evolution in Mo2C/MoS2-rGO hybrids

Abstract

Heterostructure and phase engineering are effective method to tune the electronic structure of MoS2, which can activate and boost its intrinsic catalytic activity. Herein, the theoretical calculations reveal that the free energy of H∗ adsorption (ΔGH∗) for Mo2C (−0.65 eV) is lower than MoS2 (2.05 eV), which is favorable for hydrogen adsorption. Inspired by the theoretical predictions, we develop a facile strategy to prepare nanostructured Mo2C/MoS2 dispersed on reduced graphene oxide (rGO) via a hydrothermal preparation and carburization reaction. Since the Mo2C/MoS2-rGO nanostructures with great deal of both MoS2 and Mo2C edges by heterostructure and phase engineering, which can induce massive active sites for HER on the surface of rGO, the intimate interfacial coupling effect between Mo2C and MoS2 can effectively improve the charge transfer rate. The Mo2C/MoS2-rGO catalyst exhibits exceptional HER properties, delivering a high turnover frequency (TOF) of 0.209 s−1 at an overpotential of 200 mV in 0.1 M KOH. This work may open a new window for designing NPM electrocatalysts with highly efficient HER property based on earth-abundant materials.