钒基催化剂降解氯苯的原位红外分析

V₂O₅-WO₃/TiO₂催化剂被广泛应用于脱硝，且由于V₂O₅抗氯中毒能力强，对于氯代挥发性有机物(CVOCs)的催化降解也具有较好效果。通过浸渍法制备了不同V₂O₅和WO₃含量的负载型催化剂，采用氯苯作为CVOCs的模型化合物，对催化剂进行了活性评价和原位红外实验研究，在分子层面明确V₂O₅和WO₃在氯苯催化氧化过程中的作用。结果表明：增加V₂O₅含量是提高催化剂活性和稳定性的关键；氯苯在不同活性组分上的降解途径类似，均为苯环逐渐氧化开环及后续中间产物的氧化过程；V₂O₅对氯苯具有较强的氧化能力，在100 ℃即可观察到大量中间产物，且随着温度的升高，中间产物可迅速被氧化分解。相对而言，WO₃的氧化性能很差，仅在温度达到300 ℃才可明显观察到中间产物，但V₂O₅和WO₃之间存在协同作用。以上分子层面的反应机制研究，有助于明确催化剂各组分的具体作用，进一步指导开发性能更好的钒基催化剂，用于CVOCs的催化氧化。

In-situ FT-IR analysis of chlorobenzene degradation by vanadia based catalysts

V2O5-WO3/TiO2 catalysts were widely used for denitrification in coal-fired power plants, and had good performance on catalytic degradation of chlorinated volatile organic compounds (CVOCs) due to the strong resistance to chlorine poisoning of V2O5. In this study, supported catalysts with different contents of V2O5 and WO3 were synthesized by impregnation method. Chlorobenzene was used as the model compound of CVOCs to conduct the activity evaluations and in-situ FT-IR experiments of above catalysts, and then to clarify the roles of V2O5 and WO3 in the catalytic oxidation process of chlorobenzene at the molecular level. The results showed that the increase of V2O5 content was the key to improve the activity and stability of the catalyst. The degradation pathway of chlorobenzene on different active components was similar: benzene ring opening by gradual oxidation, subsequent oxidation of the intermediates. V2O5 had a strong oxidation of chlorobenzene, and lots of intermediates could be observed at 100 ℃. And with the increase of temperature, intermediates could be rapidly oxidized and decomposed. In contrast, the catalytic performance of WO3 was very poor, intermediates could be clearly observed only when the reaction temperature reached 300 ℃, but there was a synergistic effect between V2O5 and WO3. By studying the reaction mechanism at the molecular level above, it was helpful to further develop V2O5-based catalysts with better performance for the catalytic oxidation of CVOCs.