Challenges are remaining in preparation of photocatalysts with efficient separation of charge carriers and utilization of visible light, and understanding of the reaction mechanism. In this work, B-doped Bi₂O₂CO₃ hierarchical microspheres were prepared by one-step hydrothermal treatment using bismuth citrate and sodium tetraborate as precursors. Compared with pure Bi₂O₂CO₃, the B-doped Bi₂O₂CO₃ exhibited high visible-light photocatalytic activity of removing NO to achieve efficient air purification. Combined with experiments and DFT calculations, the doped-B could induce the formation of the intermediate level near the valence band, thus increasing the visible light absorption. The B-doping could also promote the separation of electron-hole pairs and enhance the activation of reactants. Therefore, plentiful reactive could be generated and detected by ESR via the reaction between the activated small reactant molecules and separated photogenerated carriers. To reveal the reaction mechanism of photocatalytic NO oxidation, the in-situ DRIFTS method was used to study the reaction processes, and an important intermediate NO₂⁺ was found. The presence of NO₂⁺ participated in the reaction enabled favorable formation for the final product of nitrates. This work could provide a new strategy for the improvement of photocatalytic efficiency.

有效地分离载流子和利用可见光以及了解反应机理在光催化剂的制备中仍然存在挑战。在这项工作中，使用柠檬酸铋和四硼酸钠作为前体，通过一步水热处理制备了B掺杂的Bi ₂ O ₂ CO ₃分级微球。与纯Bi ₂ O ₂ CO _3相比，掺B的Bi ₂ O ₂ CO ₃表现出很高的可见光去除NO的光催化活性，以实现有效的空气净化。结合实验和DFT计算，掺杂的B可以诱导价带附近形成中间能级，从而增加可见光吸收。硼掺杂还可以促进电子-空穴对的分离并增强反应物的活化。因此，通过活化的小反应物分子与分离的光生载流子之间的反应，ESR可以生成和检测大量的反应物。为了揭示光催化NO氧化的反应机理，采用原位DRIFTS方法研究了反应过程，发现了重要的中间体NO ₂ ⁺。NO ₂ ⁺的存在参与反应使得硝酸盐的最终产物有利地形成。这项工作可以为提高光催化效率提供新的策略。