Abstract：
In the present study, we investigated the influence of surface fluorine (F) on TiO2 for the photocatalytic oxidation (PCO) of toluene. TiO2 modified with different F content was prepared and tested. It was found that with the increasing of F content, the toluene conversion rate first increased and then decreased. However, CO2 mineralization efficiency showed the opposite trend. Based on the characterizations, we revealed that F substitutes the surface hydroxyl of TiO2 to form the structure of Ti-F. The presence of the appropriate amount of surface Ti-F on TiO2 greatly enhanced the separation of photogenerated carriers, which facilitated the generation of ·OH and promoted the activity for the PCO of toluene. It was further revealed that the increase of only ·OH promoted the conversion of toluene to ring-containing intermediates, causing the accumulation of intermediates and then conversely inhibited the ·OH generation, which led to the decrease of the CO2 mineralization efficiency. The above results could provide guidance for the rational design of photocatalysts for toluene oxidation.
摘要：
在本研究中,我们研究了表面氟（F）对TiO2对甲苯光催化氧化（PCO）的影响。制备并测试了不同F含量的TiO2。发现随着F含量的增加,甲苯转化率先升高后降低。然而,CO2矿化效率呈现相反趋势。根据特征，我们揭示了F取代TiO2的表面羟基形成Ti-F的结构。TiO2上适量的表面Ti-F的存在大大增强了光生载流子的分离，这促进了·OH的产生并提高了甲苯PCO的活性。进一步表明，仅·OH的增加促进了甲苯向含环中间体的转化，导致中间体的积累，然后反过来抑制·OH的产生，导致CO2矿化效率降低。以上结果可为甲苯氧化光催化剂的合理设计提供指导。
