Insight into interface electronic structure of ZnIn₂S₄/TiO₂ heterostructure for enhanced photoelectrochemical...

Developing a high-efficiency photoelectrochemical (PEC) electrode for the glycerol oxidation reaction (GOR) is important for producing valuable products. The PEC performance could be enhanced by rationally designing heterostructures with inhibited recombination of charge carriers. Nevertheless, the interface electronic structure of heterostructures has not been comprehensively analyzed. In this work, the PEC GOR performance of ZnIn₂S₄/TiO₂ heterostructure photoanode showed 1.7 folds enhancement than that of pure TiO₂ photoanode at 1.23 V vs. RHE. The ZnIn₂S₄/TiO₂ heterostructure was simulated by constructing ZnIn₂S₄ on the TiO₂ single crystal, which was beneficial for investigating the interface electronic structure of heterostructure. Single-particle spectroscopy demonstrated a significantly increased lifetime of charge carriers. Combined with the in-situ X-ray photoelectron spectroscopy, Kelvin probe force microscopy, work function, and electron paramagnetic resonance, the interface electronic structure of the ZnIn₂S₄/TiO₂ heterostructure was proposed with a Z-scheme mechanism. This work provides a comprehensive strategy for analyzing the interface electronic structure of heterostructures.