Oxygen vacancies-modulated C-WO3/BiOBr heterojunction for highly efficient benzene degradation

Abstract

Environmental pollution and health hazards caused by volatile organic compounds (VOCs) have become critical issues due to rapid industrialization. Photocatalytic technology for treating benzene-related VOCs faces challenges, such as limited light absorption and charge recombination in photocatalysts, making the development of high-performance photocatalysts crucial. A heterojunction C-WO₃/BiOBr composite photocatalyst was successfully synthesized by introducing BiOBr onto oxygen vacancy-rich C-WO₃ nanosheets. Under 2 h of visible light irradiation, C-WO₃/BiOBr achieves a benzene degradation efficiency of 96.4 %, significantly better than pure C-WO₃ (70.4 %) and BiOBr (38.6 %). Additionally, the mineralization rate of the composite material at 3 h reaches as high as 91 %. Oxygen vacancies increase electron density, modify the band structure of C-WO₃, and broaden the light absorption range, enhancing the ability to absorb visible light. The presence of oxygen vacancies promotes the formation of an S-scheme heterojunction between C-WO₃ and BiOBr, which optimizes the migration pathways of photogenerated electrons and holes. Under the synergistic enhancement of oxygen vacancies on the heterojunction, the C-WO₃/BiOBr exhibits improved benzene adsorption and degradation, and a potential mechanism for enhanced degradation is proposed. Our study provides an efficient strategy for the degradation of gaseous benzene using the synergistic enhancement of defects on the heterojunction catalysts.