A self-adapting energy-band docking of CuGaS2@BiVO4 S-scheme structure for efficient photoelectrochemical hydrogen production

Abstract

Typical p-n junctions have emerged as a promising strategy for contending with charge carrier recombination in solar conversion. However, the photo-corrosion and unsuitable energy band positions still hinder their practical application for hydrogen production from water in photoelectrochemical systems. Here, an in-situ photo-oxidation method is proposed for achieving self-adapting activation of BiVO₄-based photoanodes with surface-encapsulated CuGaS₂ particles by the ZnO layer. The self-adapting activation demotes the energy band positions of CuGaS₂, establishing an S-scheme structure with BiVO₄, resulting in an efficient p-n junction photoanode. The optimal sample exhibits enhanced photocurrent and an onset potential cathodically shifted by ~ 300 mV compared with BiVO₄, which is attributed to significantly enhanced charge transport and transfer efficiencies. As expected, it attains the highest photocurrent value of 5.87 mA·cm⁻², aided by a hole scavenger at 1.23 V versus a reversible hydrogen electrode, which significantly surpasses that of BiVO₄ (4.32 mA·cm⁻²).