Young C, Lim T M, Chiang K, Amal R
Centre for Particle and Catalyst Technologies, School of Chemical Engineering and Industrial Chemistry, The University of New South Wales, Sydney, NSW, 2052, Australia.
Water Sci Technol. 2004;50(4):251-6.
A photoreactor has been set up to study the photodegradation of volatile organic compound (VOC) in situ. In the reactor, TiO2 and Pt/TiO2 photocatalysts were immobilized on to UV-transparent quartz support. Scanning electron microscope (SEM) studies and Brunauer-Emmett-Teller (BET) surface area measurements revealed that the quartz fiber support was mostly coated with catalyst with a total surface area of 4.0 +/- 0.3 m2/g. The photocatalytic activity of the photocatalysts was evaluated for the photodegradation of 160 ppm toluene-laden air. It was found that 50-70% of toluene was degraded within the first 5 min of UV illumination. Both TiO2 and Pt/TiO2 photocatalysts suffered from deactivation after 18 hours of continuous operation, and the photocatalysts' activity was significantly reduced. However, platinization doubled the photocatalyst life and delayed the onset of de-activation. The presence of moisture was found to shift the onset of catalyst de-activation to an earlier time. It is concluded that the de-activation of the photocatalyst was due to the accumulation of intermediates on the photocatalysts surface preventing the toluene being adsorbed on the photocatalyst surface for degradation.
已搭建一个光反应器用于原位研究挥发性有机化合物（VOC）的光降解。在该反应器中，TiO₂和Pt/TiO₂光催化剂被固定在可透过紫外线的石英载体上。扫描电子显微镜（SEM）研究和布鲁诺尔-埃米特-泰勒（BET）表面积测量结果表明，石英纤维载体大多被催化剂覆盖，总表面积为4.0±0.3 m²/g。针对含160 ppm甲苯的空气的光降解，对光催化剂的光催化活性进行了评估。结果发现，在紫外线照射的前5分钟内，50%-70%的甲苯被降解。TiO₂和Pt/TiO₂光催化剂在连续运行18小时后均出现失活，且光催化剂的活性显著降低。然而，铂化使光催化剂寿命延长了一倍，并延迟了失活的开始时间。发现水分的存在会使催化剂失活的起始时间提前。得出的结论是，光催化剂的失活是由于中间体在光催化剂表面的积累，阻止了甲苯吸附在光催化剂表面进行降解。
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