Oxygen Vacancy-Dependent Reactive Oxygen Species Generation over Defect-Engineered Bi 2 O 3 for Efficient Visible Light-Driven NO Deep Oxidation

作者：Yanfeng Lu, Yuhui Du, Yilin Liu, Yurou Xiong, Zhuoying Wu, Yu Huang, Yiming Xie, Shi‐Min Zhao, Shun Cheng Lee · 发表于：ACS ES&T Engineering · 年份：2025 · DOI：10.1021/acsestengg.5c00596 · 被引用次数：6 · 研究领域：Catalytic Processes in Materials Science、Advanced Photocatalysis Techniques、Gas Sensing Nanomaterials and Sensors

Oxygen-vacancy engineering was exploited to create vacancy-rich Bi 2 O 3 nanosheets (denoted Defect -BO) by in situ pyrolysis under an inert atmosphere, alongside vacancy-free Bi 2 O 3 (denoted BO) calcined in air. Defect -BO achieved a high NO removal rate of 38% and long stability under visible-light (λ ≥420 nm) irradiation while strongly suppressing toxic NO 2 formation and retaining activity over repeated cycles. Besides, the surface oxygen vacancies serve both as low-energy adsorption-activation sites (stabilizing an NO + intermediate) and as localized defect states that lower the excitation energy, favor triplet-exciton formation, and enable efficient energy transfer to adsorbed O 2, thereby generating singlet oxygen ( 1 O 2 ). The simultaneous production of 1 O 2 and hydroxyl radicals ( • OH) drives a synergistic pathway in which NO is rapidly oxidized to nitrate, avoiding NO 2 accumulation. Electron-paramagnetic-resonance and O 2 -TPD experiments confirm fast, vacancy-mediated O 2 activation, whereas in situ DRIFTS tracks the evolution of NO +, NO 2 –, and NO 3 – surface species, validating the proposed mechanism. Continuous regeneration of 1 O 2 sustains reactive oxygen species (ROS) levels, accounting for the catalyst’s durability. This work discloses a previously unrecognized oxygen-activation route and furnishes a design principle for highly efficient, selective photocatalysts for gaseous pollutant abatement.