TiO2光催化净化城市隧道中NOx的行为及经济性

考察了TiO₂光催化降解模拟城市隧道尾气中NO_x的催化行为，并以一个长度为1km和高度为5m的双向两车道城市隧道为研究对象，分析了其应用的经济性.结果表明，煅烧温度为400℃制备的TiO₂-400催化剂的NO吸附性能和光催化性能最佳，NO_x最大转化率为30%.不同的气体组成会显著影响光催化剂对NO_x的吸附和光催化性能，其中对于NO竞争性吸附抑制效应的影响为CH₄≈CO₂>CO，而对于光催化性能的促进效应影响为CO > CH₄ > CO₂.增大紫外光辐照度可提高光催化活性，但降低了催化剂的稳定性.紫外光辐照度为6.4μW/cm²为合适的光照强度.增加催化剂的用量可显著增强NO的吸附性能和光降解NO_x的稳定性.当催化剂用量为15mg/cm²时，NO吸附容量为0.88mg/g，催化剂的稳定时间可达110min.通过简要分析该技术的经济性，表明光催化降解城市隧道NO_x的成本较低，具有良好的经济性.

Photocatalytic performance and economy of de-NOx in urban tunnel exhaust by TiO2

Photocatalytic behavior of NO removal on TiO₂ was carried out in the simulated urban tunnel exhaust. The economy of its application was analyzed for an urban tunnel with length of 1km and height of 5m. TiO₂ calcined at 400℃ (TiO₂-400) showed the best adsorption and photocatalytic performance among the samples. The maximum NO_x conversion of 30% was obtained on TiO₂-400. NO_x adsorption and photocatalytic performance was significantly influenced by various feeding gases. The inhibition of NO_x adsorption decreased in the order of CH₄≈CO₂ > CO. The promotion of removal efficiency of NO_x was ranked as CO > CH₄ > CO₂. When the light irradiance increased, the photocatalytic activity and stability of catalyst were enhanced and decreased, respectively. Light irradiance of 6.4ugW/cm² is the appropriate illumination intensity for photocatalysis of DeNO_x. Both NO adsorption capacity and lifetime of catalyst were significantly promoted with the increase of catalyst usage. When catalyst dosage was 15mg/cm², the adsorption capacity of NO was 0.88mg/g, and the stabilization time of the catalyst was 110min. This technology has characteristics with low cost and good economy.