Unlocking the Electrocatalytic Potential of Sb₂Se₃ for HER via Cu Doping-Induced Phase Conversion and rGO Integration

In this study, we explore the electrocatalytic hydrogen evolution reaction (HER) performance of Cu-doped Sb2Se3 anchored to reduced graphene oxide (rGO). Although pristine Sb2Se3 is typically inactive for HER, its activity is significantly enhanced through Cu doping and integration with rGO, achieved via a one-step hydrothermal process. The resulting CuSbSe2-rGO catalyst benefits from the synergistic interaction between rGO and Cu, exhibiting superior HER activity compared with control samples: Sb2Se3, Sb2Se3-rGO, and CuSbSe2. The electrochemical characterization demonstrates that rGO incorporation enhances stability, conductivity, and surface area. The optimized CuSbSe2-rGO catalyst shows enhanced HER performance, with an onset potential of 293 mV, an overpotential of 386 mV at a current density of 10 mA cm–2, and a Tafel slope of 158 mV dec–1. The catalyst’s superhydrophilic surface (contact angle <5°) promotes efficient wetting and ion diffusion, further improving HER efficiency. Density functional theory calculations indicate that Cu doping reduces the band gap of Sb2Se3 from 1.31 to 1.16 eV due to the distribution of Cu states near the Fermi level, a modification that likely contributes to the observed reduction in the overpotential requirements. These findings highlight the potential of CuSbSe2-rGO for the advancement of water electrolysis technologies.