Construction of alkaline media via ZnIn2S4/ZnCoP ohmic junction for efficient photocatalytic hydrogen evolution

Efficient photocatalytic hydrogen evolution requires optimizing a catalyst of adsorption properties. Pristine ZnIn2S4 demonstrates limited hydrogen evolution kinetics, primarily due to its weak adsorption capacity for H2O and H+. This study addresses this limitation by constructing a ZnIn2S4/ZnCoP ohmic junction via an interfacial engineering strategy, where a ZnCoP co-catalyst is loaded onto the ZnIn2S4 surface. Density functional theory (DFT) confirms this ZnIn2S4/ZnCoP interface significantly lowers the hydrogen adsorption of Gibbs free energy (ΔGH*). The ZZ-5 exhibits exceptional activity, with H2 evolution rates 7.8 times higher than pure ZnIn2S4. Photoelectrochemical characterizations verify the ohmic junction markedly enhances spatial separation and migration of photogenerated carriers. Bader and differential charge density charge analyses elucidate the mechanism of directional interfacial charge transfer. Consequently, ZZ-5 exhibits superior performance in alkaline media. This investigation provides an in-depth analysis of the relationship between ohmic contact formation and the modulation of carrier dynamics. Furthermore, it offers essential experimental evidence for enhancing the versatility of photocatalysts across various reaction environments.