The application of photocatalytic oxidation (PCO) in VOCs degradation is greatly hindered at high humidity levels. This is because VOCs compete with water molecules to adsorb on the generally hydrophilic photocatalyst surface, where photocatalytic reactions take place. Modified P25-TiO₂ nanoparticles with surface fluorination (F-P25) was prepared to reduce the surface hydrophilicity of Degussa P25. The prepared samples were characterized by BET, SEM, and XPS tests. Herein, the effects of surface fluorination on the adsorption capacity of P25-TiO₂ nanoparticles towards toluene, methyl ethyl ketone (MEK), and isobutanol, representing different classes of indoor air pollutants, were investigated. After surface fluorination, the adsorption capacity of modified TiO₂ was compared to bare-TiO₂ in a continuous reactor at four different relative humidity levels (i.e., 0, 20, 40, and 60%). Three adsorption isotherms, including Langmuir, Freundlich, and BET, were used to model the adsorption experimental data. The equilibrium data for the adsorption of all compounds showed the best fit with the BET model, and the Freundlich model also represented a good fit. Moreover, the results indicated that the surface fluorination of P25 increased adsorption capacity about two times for toluene in three humid conditions (0, 20, and 40%) compared to bare-P25. By combining the benefits of using an easy modification method by a low-cost modifier and using P25-TiO₂, which is the most common commercialized photocatalyst, an effective method has been developed to enhance the efficiency of VOCs removal in indoor air environments.

在高湿度下，光催化氧化（PCO）在VOC降解中的应用受到极大的阻碍。这是因为VOC与水分子竞争，以吸附在通常发生光催化反应的亲水性光催化剂表面上。制备了具有表面氟化作用的改性P25-TiO ₂纳米颗粒（F-P25），以降低Degussa P25的表面亲水性。通过BET，SEM和XPS测试对制备的样品进行表征。在此，研究了表面氟化对代表不同类别的室内空气污染物的P25-TiO ₂纳米颗粒对甲苯，甲乙酮（MEK）和异丁醇的吸附能力的影响。表面氟化后，改性TiO ₂的吸附能力在四个不同的相对湿度水平（即0％，20％，40％和60％）下，将其与连续反应器中的TiO-TiO ₂进行比较。三种吸附等温线（包括Langmuir，Freundlich和BET）用于模拟吸附实验数据。所有化合物吸附的平衡数据均显示出与BET模型的最佳拟合，而Freundlich模型也代表了良好的拟合。此外，结果表明，与裸露的P25相比，P25的表面氟化作用在三种潮湿条件下（0％，20％和40％）对甲苯的吸附能力提高了约两倍。通过结合使用低成本改性剂的简便改性方法和使用P25-TiO ₂的优点作为最常见的商业化光催化剂，已开发出一种有效的方法来提高室内空气环境中VOC的去除效率。