Composites of transition metal dichalcogenides and topological insulators as catalytic materials for HER

Abstract

To produce materials with enhanced catalytic activity toward hydrogen evolution reaction we combined MoS2 as transition metal dichalcogenide and Bi2Se3 as topological insulator. The composites were produced by three methods: mechanical milling, high power sonication and spin-coating. MoS2 and Bi2Se3 as precursors in composites preparation were synthesized by hydrothermal method. The structure and morphology of various composites were correlated with their electrochemical properties obtained by impedance spectroscopy, linear sweep and cyclic voltammetry. Mechanical milling provided composites with the most pronounced activity improvement as a result of the largest damage and amount of introduced defects into the materials structure. The potential required to achieve the current density of 10 mA/cm2 in these samples is lowered up to 50 mV compared to as-synthesized material. Bi2Se3 in composite materials promotes the electron transfer to MoS2 which leads to the decrease of charge transfer resistance by 25 Ω.