In situ doping and vacancy strategy trigger rapid charge transport of Cu/S-In(OH)3 for boosting photocatalytic hydrogen production

In this study, we developed a synergistic modulation strategy through in situ dual-anion/cation doping coupled with vacancy engineering, demonstrating a direct ammonia etching approach to synthesize Cu/S-In(OH) 3 with controlled indium vacancies (V In ) from CuInS 2 precursors. This in situ doping approach provides a uniform distribution of Cu cations and S anions throughout the material, overcoming conventional doping heterogeneity. Simultaneously, an indium vacancy (V In ) structure was precisely engineered and regulated through a growth limitation strategy. The synergistic interplay between the uniformly dispersed anions, cations and V In significantly suppresses the recombination of photogenerated carrier within In(OH) 3 , thereby allowing more carriers to participate in the surface catalytic reaction. Both experimental and theoretical analyses demonstrate that the introduction of V In into the defective states leads to a direct reduction in the band gap, significantly improving photocatalytic hydrogen evolution performance. The optimized Cu/S-In(OH) 3 with V In achieves a photocatalytic hydrogen production rate of 1.22 mmol g −1  h −1 , approximately 122 times higher than that of pure In(OH) 3 (0.01 mmol g −1  h −1 ). This work establishes a paradigm of integrating in situ doping and vacancy engineering strategies to rationally design In(OH) 3 -based materials, offering generalizable principles for advanced catalytic applications.