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研究报告

尹发平,黄碧纯,俞潇舞,叶代启.原位红外光谱法研究CdS-TiO₂/MWCNTs可见光光催化降解气相甲苯[J].环境科学学报,2011,31(9):1881-1886

In situ FTIR study on photocatalytic degradation of gas-phase toluene over CdS-TiO₂/MWCNTs under visible light irradiation

基金项目：国家高技术研究发展计划 (863)项目(No. 2006AA06A310); 广东省科技计划项目(No. 2008B050100007,2009B050900005)

摘要：通过原位红外光谱技术研究了可见光下甲苯在CdS-TiO₂/MWCNTs(多壁碳纳米管)和CdS-TiO₂光催化剂表面的吸附、光催化降解过程,并考察了水汽对光催化反应的影响.结果表明,在吸附过程中甲苯在CdS-TiO₂和CdS-TiO₂/MWCNTs光催化剂表面就能被氧化成苯甲醛、苯甲酸等中间产物,水汽的存在有利于提高光催化剂的活性,促进甲苯氧化成CO₂.光催化过程中苯甲酸的深度氧化是整个反应的速率控制步骤,苯甲醛、苯甲酸等中间产物的积累是导致光催化剂失活的原因之一.在本实验条件下,甲苯在CdS-TiO₂和CdS-TiO₂/MWCNTs表面的光催化降解过程符合一级反应动力学方程.

Abstract：Under visible light irradiation, in situ infrared spectroscopy was used to analyze the adsorption and photocatalytic degradation of gas-phase toluene over CdS-TiO₂ and CdS-TiO₂/MWCNTs. The effect of humidity on the photocatalytic reaction was also discussed. Our research results indicated that benzaldhyde and benzoic acid were identified on the surface of CdS-TiO₂ and CdS-TiO₂/MWCNTs during the adsorption process. Humidity plays an important role in the photocatalytic oxidation toluene to CO₂. The deep oxidation of benzoic acid may turn to be the rate-controlling factor of the photocatalytic oxidation of toluene. The accumulation of benzaldhyde and benzoic acid was one of the reasons for the photocatalysts deactivation. The photocatalytic degradation of toluene followed the first-order chemical kinetics equation under our experimental conditions.