Promoting the electron/hole co-extraction using piezotronic effect in Pt/ZnIn2S4/BaTiO3 heterojunctions for photocatalytic synergistic hydrogen evolution and HMF oxidation

Efficient spatial separation of photogenerated carriers is the key to achieving photocatalytic oxidation reduction synergistic reactions, and the built-in electric field generated by piezoelectric effects can provide a strong driving force for charge separation. A novel Pt/ZnIn2S4/BaTiO3 (PBZIS) piezo-photocatalyst with spatial charge separation was successfully constructed through two-step hydrothermal and photodeposition methods. Due to the special 1D/2D core/shell structure, the inner BaTiO3 can served as hole-storage layer, while the outer Pt nanoparticles can acted as electron capture center, thus greatly improving the separation of photo generated charge carriers and achieving spatial separation of redox sites. Under the ultrasound, the polarized electric field induced by the piezoelectric effect can further improve the extraction rate of photo generated holes by BaTiO3 and accelerate surface catalytic reactions. Therefore, the synergism of electron/hole co-extraction and piezoelectric effect construct a directional transmission channel and target active sites for photogenerated electron-holes over PBZIS heterojunctions, reuslting in the highest performance for photocatalytic cooperative H2 evolution (1335.3 μmol g−1 h−1) and HMF oxidation (1070.8 μmol g−1 h−1). This work would inspire the development of high-performance piezo-photocatalysts for the cooperative biomass oxidation coupling with high efficient hydrogen evolution.