Improved Hydrogen Evolution Reaction Performance using\nMoS₂–WS₂ Heterostructures by Physicochemical\nProcess

Abstract

This\nreport describes the synthesis of a layered molybdenum disulfide\n(MoS₂)–tungsten disulfide (WS₂) heterostructure\nonto fluorine doped tin oxide covered glass substrates using a combination\nof chemical bath deposition and RF sputtering techniques. FESEM images\nrevealed that the MoS₂–WS₂ heterostructure\nsurface consisted of a cauliflower structured array of grains with\nspherical structures. The vertically aligned atomic layers were explored\nby transmission electron microscopy images for MoS₂–WS₂ heterostructure. Hydrogen evolution reaction (HER) kinetics\nshow overpotentials of 151 and 175 mV @ 10 mA/cm² with\nTafel slope values of 90 and 117 mV/decade for pristine MoS₂ and WS₂ electrocatalysts, respectively. Improved electrocatalytic\nactivity for HER was established with overpotential 129 mV @ 10 mA/cm² and Tafel slope 72 mV/decade for the MoS₂–WS₂ heterostructure. The MoS₂–WS₂ heterostructure electrocatalyst showed robust continuous HER performance\nover 20 h in an acidic solution. This improved electrochemical performance\nemerges from the elevation of electron–hole separation at the\nlayer interfaces and sharing of active edge sites through the interface.\nThis study provides the basis to develop new applications for transition-metal\ndichalcogenides heterostructures in future energy conversion systems.