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综述了作者近年来在火焰化学气相沉积(CVD)法制备多晶纳米二氧化钛及其在光催化气体净化中应用的研究成果。总结了以工业丙烷为燃料、空气为催化剂、四氯化钛为先驱物的火焰CVD法制备多晶纳米二氧化钛中热负荷对燃烧室内的温度分布和金红石含量的影响。以光致发光(PL)光谱为表征手段,研究了金红石含量对光激电子和空穴的分离作用。用管式光催化反应系统,研究了初始浓度和相对湿度对多晶纳米二氧化钛光催化降解挥发性有机物(VOC)气体和氨气的影响,及最佳光催化效率的金红石含量。针对多晶纳米二氧化钛在低相对湿度下光催化降解效率低的缺陷,用复合法对其性能进行了改进,研究了改进的光催化剂在低相对湿度和干燥空气中光催化降解苯的效率。对500 m3/h模块化的填料式光催化气体净化设备进行了净化效率和催化剂寿命实验,讨论了光催化饱和浓度对净化设备设计的影响。
In this paper, the authors reviewed the recent progress in the preparation of polycrystalline nano-titanium dioxide by flame chemical vapor deposition (CVD) and its application in the photocatalytic gas purification. The effects of thermal load on the temperature distribution and rutile content in the combustion chamber prepared by flame CVD method using industrial propane as fuel, air as catalyst and titanium tetrachloride as precursors were summarized. Using photoluminescence (PL) spectroscopy as a characterization tool, the effect of rutile content on photo-induced electron and hole separation was studied. The effects of initial concentration and relative humidity on the photocatalytic degradation of volatile organic compounds (VOCs) and ammonia and the photocatalytic efficiency of rutile polycrystalline nano-titanium dioxide were investigated by using tubular photocatalytic reaction system. Aiming at the defects of low photocatalytic degradation efficiency of polycrystalline nano-titania at low relative humidity, its performance was improved by composite method. The photocatalytic degradation efficiency of benzene in low relative humidity and dry air was studied. The purification efficiency and catalyst life of 500 m3 / h modular packed photocatalytic gas purification equipment were tested, and the influence of photocatalytic saturation concentration on purification equipment design was discussed.