二次有机气溶胶（SOA）和O3消减是我国现阶段大气污染治理的关键问题之一。光催化过程产生强氧化性自由基，已被证实可消减NOx、典型挥发性有机物等前体物，有望成为抑制SOA和O3生成的重要手段。但目前多组分条件下光催化自由基反应过程尚不明确，其对于多组分体系光化学反应影响机制缺失，限制了光催化材料性能评估与优化。针对上述问题，本项目拟选取具有高SOA及O3生成潜势的NO/二甲苯二元混合体系，采用自由基捕获实验和反应动力学分析的方法，分析光催化材料表面自由基生成与反应机制，探究光催化自由基对NO/二甲苯体系气-气均相、气-固非均相反应的影响规律，揭示光催化过程对于SOA和O3生成的抑制作用机理。在此基础上，从光催化自由基调控的角度出发，通过构筑N-掺杂石墨烯/TiO2复合体系，优化材料性能，实现对于SOA和O3的稳定、高效抑制，为光催化技术在空气净化领域的应用提供理论基础和新材料。

The reduction of secondary organic aerosol (SOA) and O3 has become an important part in the air pollution control project of our country at the current stage. Reactive radicals generated by photocatalysts have been proven to oxidize and decompose precursors such as NOx and typical volatile organic compounds (VOCs), which makes it a potential way for inhibiting SOA and O3. However, the reactions of photocatalytic radicals under multi-component conditions are still unclear, which holds back the understanding of their influences on the gas-gas homogeneous and gas-solid heterogeneous reactions, and further limits the optimization of photocatalysts. This project intends to choose the NO/xylene mixed system with high SOA and O3 formation potential as the research target. The impacts of reactive radicals on the photochemical reactions of the NO/xylene system will be explored through scavenger reactions and kinetic analysis to reveal the key factors that influence the inhibition of SOA and O3 by photocatalytic processes. A method for the optimization of photocatalysts will be proposed by analyzing the roles of photocatalytic free radicals. By constructing N-doped graphene/TiO2 composites, the generation of reactive radicals will be optimized to achieve the stable and effective inhibition of SOA and O3. This project will provide theoretical basis and new methods for the application of photocatalytic technology in the field of air purification.