ZSM-5负载Ce-Co催化氧化NO的机理研究

A Theoretical Study on the Oxidation of NO Catalyzed by ZSM5 Supported Ce-Co

利用量子化学对ZSM5负载Ce-Co催化氧化NO进行详细地机理研究。采用UB3LYP//SDD方法计算得到相关反应的反应物、过渡态、中间体及产物,分析反应路径,计算获得活化能。结果表明：相比NO直接氧化（135.5 kJ/mol）,ZSM5负载Co催化氧化NO的反应活化能（80.60 kJ/mol）显著降低,说明ZSM5-Co对NO氧化具有明显的催化效果;ZSM5-Ce-Co催化氧化NO活化能（31.71 kJ/mol）明显低于ZSM5-Co催化（80.60 kJ/mol）,说明在ZSM5-Co中掺杂Ce可进一步降低反应活化能,提高催化效率。研究表明,NO催化氧化不仅取决于催化剂的过渡金属（Co）,也与催化剂活性中心（Ce）高度相关。

The detailed mechanism of NO oxidation catalyzed by the ZSM5 supported Ce-Co was investi- gated by Quantum Chemistry Calculation. Theoretical results showed that, the activate energies of reactions catalyzed by ZSM5-Co （80.60 kJ/mol） were quite lower than those obtained from the direct NO oxidation （ 135.5 kJ/mol） ,which indicated that ZSM-5 supported Co had an evident catalytic effect. When the ac- tive center Si was replaced by Ce ,the activation energy was further decreased to 31.71 kJ/mol ,which in- dicated that the catalytic effect was significantly improved. The theoretical study indicated that the catalyst for NO oxidation is not only related to the supported transition metal such as Co, but also highly related to the activity center such as Ce.