ZnO纳米粒子多相催化n-C7H16-SO2气相光化学反应的研究

利用自制的ZnO纳米粒子和商品的ZnO粒子，研究了ZnO粒子多相催化n-C6H16- SO2的气相光化学反应。利用气相色谱－质谱联用仪（GC／MS）和气相色谱仪（GC ）对反应物n-C6H16和SO2以及主要气相产物3－庚酮进行了定量分析，考察了不同 条件下它们的降解和产生趋势，初步探讨了氧气和水蒸气对ZnO粒子多相催化n- C7H16-SO2气相光化学反应的影响，并对反应的一些现象作了描述及相应的说明。 结果表明，无论有无氧化存在，ZnO粒子均能够对n-C7H16-SO2的气相光化学反应起 一定的催化作用，但是有氧气的催化活性比无氧气的高。这可能说明了ZnO的光催 化作用主要与生成的活性氧物种（O^*)有关，同时光致空穴（h^+）也能够直接引 发氧化反应；虽然ZnO纳米粒子的光催化活性随着焙烧温度的升高而降低，但是均 比商品的高。而在模拟大气的条件下，ZnO纳米粒子对n-C7H16SO2的气相光化学反 应有很大的影响，大大地促进了n-C7H16和SO2的降解，这说明ZnO纳米粒子的存在 对大气中SO2－烃的气相光化学反应的影响是不容忽视的。此外，对ZnO粒子多相催 化n-C7H16-SO2气相光化学反应的机理进行了探讨。

Study on n-C_7H_(16)-SO_2 Gas Phase Photochemical Reaction Catalyzed Heterogeneously on ZnO Nanoparticles

The n-C_7H_ 16-SO_2 gas phase photochemical reaction catalyzed heterogeneously on ZnO particles was studied by using the home-made ZnO nanoparticles and commercial ZnO particles. The degradation or production trends of reactants n-C_7H_ 16 and SO_2 and the main gas product 3-heptanone were investigated by their quantitative analysis using GC/MS and GC methods. The effects of O_2 and H_2O gases on the heterogeneous catalysis in n-C_7H_ 16-SO_2 gas phase photochemical reaction on ZnO particles were also primarily discussed, and the reactive phenomena were simply described. The results show that the ZnO particles have considerable catalytic effects on n-C_7H_ 16-SO_2 gas phase photochemical reaction regardless of the existence of O_2, but the catalytic activity with O_2 is higher than that without O_2. This indicates that the catalytic effects of ZnO may mainly result from the produced active oxygen species (O *), at the same time the photo-induced hole (h +) could also directly induce oxidation reaction. The photocatalytic activity of ZnO nanoparticles is higher than that of commercial ZnO particles although the activity decreases as the calcination temperature increases. Under the condition of simulated atmosphere, the ZnO nanoparticles have strong effects on n-C_7H_ 16-SO_2 gas phase photochemical reaction, greatly promoting the degradation of n-C_7H_ 16 and SO_2, which shows that the effects of ZnO nanoparticles in the atmosphere on the hydrocarbon-SO_2 gas phase photochemical reaction can not be ignored. In addition, mechanisms of the heterogeneous catalysis in n-C_7H_ 16-SO_2 gas phase photochemical reaction was also discussed.