The selectivity for different intermediates in VOCs degradation process may lead to different reaction paths, which determines the overall pollutant degradation efficiency. In this work, Ca₂Sb₂O₇ shows a superior photocatalytic activity and stability in gaseous toluene degradation as compared to P25. To shed light on the mechanism of efficient and stable toluene degradation, particularly the role of selectivity for intermediates during the reaction process, the theoretical and experimental approaches were closely combined. Owing to the promoted charge transfer between the absorbents (such as O₂, H₂O, toluene and other intermediates) and Ca₂Sb₂O₇, both the ROS generation and principal intermediates adsorption are significantly enhanced, which leads to a high selectivity for benzoic acid formation. That is confirmed by in suit DRIFTS and theoretical calculations. Enhanced generation of benzoic acid on Ca₂Sb₂O₇ surface could improve the efficiency of toluene ring-opening and over-all degradation due to lower energy barrier for toluene transformation into benzoic acid. Thus, this could enable efficient and stable degradation of toluene and prevent the catalyst from deactivation. This work provides new insight into the mechanistic understanding of photocatalytic VOCs degradation reaction.

VOCs降解过程中不同中间体的选择性可能导致不同的反应路径，这决定了总体污染物降解效率。在这项工作中，与P25相比，Ca ₂ Sb ₂ O ₇表现出优异的光催化活性和气态甲苯降解稳定性。为了阐明有效和稳定的甲苯降解机理，特别是反应过程中中间体选择性的作用，将理论和实验方法紧密结合。由于吸收剂（例如O ₂，H ₂ O，甲苯和其他中间体）和Ca ₂ Sb ₂ O之间的电荷转移促进了_{如图7所示}，ROS的产生和主要中间体的吸附均显着增强，这导致对苯甲酸形成的高选择性。适当的DRIFTS和理论计算已证实了这一点。由于降低了甲苯转化为苯甲酸的能垒，因此在Ca ₂ Sb ₂ O ₇表面上增加的苯甲酸生成可以提高甲苯开环和整体降解的效率。因此，这可以使甲苯有效和稳定地降解并防止催化剂失活。这项工作提供了对光催化VOC降解反应机理的新认识。