Substrate induced optimization of the Electrocatalytic Hydrogen Evolution Reaction (HER) performances of MoS2 thin film

Abstract

Molybdenum disulfide (MoS2) has emerged as a promising, cost-effective catalyst for hydrogen production via water splitting. We investigate the structural and electrocatalytic properties of MoS2 thin films deposited on different substrates (Al2O3, SiC, STO) to study their hydrogen evolution reaction (HER) activity. In particular, in order to study the substrate influence on the stabilization of different polymorphic MoS2 phases, the films are synthesised using pulsed laser deposition on substrates with different crystal symmetries and lattice parameters. All the deposited samples are characterized by X-Ray Diffraction, Raman Spectroscopy, Linear Sweep Voltammetry and Electrochemical Impedance Spectroscopy analyses. The films grown on Al2O3 substrates exhibit the best HER performance, likely due to the stabilization of the metastable 1T phase through the interfacial interactions between film and substrate. Presence of the 1T phase in the samples grown on Al2O3 improves the charge transfer efficiency and the electrochemically active surface with a better response to the applied potential, demonstrating their enhanced catalytic behaviour for hydrogen evolution.