Phase engineering and morphology modulation of Cu–S induced by Cr introduction for improved electrocatalytic hydrogen evolution reaction performance

Cu 2 S and Cu–S based materials with the introduction of 15 at% and 63% at% Cr respectively were prepared on carbon cloth (CC) (Cu 2 S/CC, Cu 5.6 CrS 6 /CC and CuCr 1.4 S 5 /CC) by one-pot hydrothermal synthesis. It was found that the phase composition and morphology of Cu–S undergo significant changes with the introduction of Cr content, thereby impacting their electrocatalytic hydrogen evolution reaction (HER) properties. In particular, for Cu 5.6 CrS 6 /CC, 15 at% Cr introduction facilitated the formation of a highly catalytically active Cu 7 S 4 -dominant phase and a hexagonal flake-like morphology with a large specific surface area conducive to fully exposing the catalytically active sites. The synergistic advantages in morphology and phase composition endow Cu 5.6 CrS 6 /CC with the best HER electrocatalytic performance with a low overpotential of 81 mV (10 mA cm −2 ) and 142 mV (100 mA cm −2 ), a Tafel slope of 43 mV dec −1 , and 10000 cycle stability. This study provides an idea for implementing a synergistic strategy of phase engineering and morphology modulation by introducing Cr to construct high-performance HER catalysts.