One-pot synthesis of MoS2/WS2 ultrathin nanoflakes with vertically aligned structure on indium tin oxide as a photocathode for enhanced photo-assistant electrochemical hydrogen evolution reaction

Abstract

A hierarchical structure composed of vertically aligned ultrathin two dimensional (2D) MoS₂/WS₂ nanosheets is fabricated through a facile one-pot hydrothermal reaction. Scanning electron microscope (SEM), transmission electron microscope (TEM) and photoluminescence (PL) indicate that the MoS₂/WS₂ hybrid shows ultrathin nanoflakes with a thickness of 2–10 nm, and the as prepared heterostructure markedly enhances the separation of electro–hole pairs. Benefiting from the integrated W-doped MoS₂, the vertically aligned nanostructure exhibits a moderate degree of disorder and increased active surface area. Electrochemical measurements (cyclic voltammetry (CV), linear sweep voltammetry (LSC) and electrochemical impedance spectroscope (EIS) under light illumination or in dark) indicated that the MoS₂/WS₂ hybrid (especially the hybrid with Mo : W of 1/1) exhibits much better photo-and electrochemical performance than its counterpart of pure MoS₂ or WS₂, which made it a promising photocathode for electrocatalytic hydrogen evolution reaction (HER) by photo-assistance.