Energy band engineering of WO3/Bi2WO6 direct Z-scheme for enhanced photocatalytic toluene degradation

Photocatalytic removal of volatile organic compounds with high efficiency has great potential in environmental protection. Herein, WO3/Bi2WO6 (WBWO) composite in a direct Z-scheme was fabricated by a simple hydrothermal process for efficient photocatalytic removal of toluene. WBWO-3 (the mass ratio of WO3 and Bi2WO6 is 3:1) presented the highest photocatalytic toluene conversion rate of 92 % within 60 min, which was much better than pure WO3 (45 %) and Bi2WO6 (63 %). The excellent photocatalytic performance of WBWO benefits from constructing a direct Z-scheme of energy band structure, which promotes effective charge separation while retaining the intrinsic redox capacity of the catalyst. The mechanism studies revealed that hydroxyl radical (·OH) and superoxide radical (·O2–) are the important active radicals in photocatalytic toluene oxidation. Meanwhile, a series of intermediates were identified by in situ diffuse reflectance infrared Fourier transform spectroscopy (in-situ DRIFTS), which revealed the reaction pathways for the efficient conversion of toluene. This study provides a new perspective for designing catalysts with a direct Z-scheme for efficient photocatalysis catalysis.