A direct Z-scheme mechanism for selective hydrogenation of aromatic nitro compounds over a hybrid photocatalyst composed of ZnIn2S4 and WO3 nanorods

Abstract

Nowadays, visible-light-driven photocatalysts are considered to be prospective candidates for solving the crisis of energy shortage and environment pollution. Herein, with the support of WO₃ nanorods (NRs), which possess a fast electron transmission and low carrier diffusion, a series of direct Z-scheme ZnIn₂S₄/WO₃ photocatalysts are exquisitely fabricated by an in situ self-assembly route with ZnIn₂S₄ (ZIS) and WO₃ NRs. Photocatalytic activities towards both selective hydrogenation of aromatic nitro compounds and non-selective oxidation of organic compounds demonstrate that these as-fabricated heterostructured nanocomposites exhibit remarkably enhanced photocatalytic activities owing to the highly efficient separation of photogenerated electrons and holes. Furthermore, the characteristics of electron spin resonance (ESR) spectra clearly suggest that the as-fabricated nanocomposites follow the direct Z-scheme-dominated photoredox catalytic mechanism. Additionally, combining the results of ESR and X-ray photoelectron spectroscopy (XPS), it can be concluded that the photo corrosion of ZnIn₂S₄ is significantly postponed after integration with WO₃ NRs. Finally, we will be greatly pleased if this work could afford a theoretical exemplification and synthetic strategy for rationally designing and utilizing direct Z-scheme photocatalysts.