ZSM-5负载Mn/Co催化氧化NO的机理研究

Quantum Chemistry Study on the Oxidation of Nitric Oxide Catalyzed by ZSM-5-supported Mn/Co

利用量子化学密度泛函理论,对负载在分子筛ZSM-5上的Mn,Co催化氧化NO的反应机理进行了研究.采用UB3LYP//SDD方法计算优化得到相关反应的反应物、过渡态、中间体及产物,分析得到反应路径,并计算获得反应活化能.结果表明,相比NO直接氧化(135.5kJ/mol),MnZSM5及Co-ZSM5催化氧化NO具有更低的活化能(71.1kJ/mol及80.6kJ/mol),具有明显的催化效果;而Mn-ZSM5对NO氧化反应的催化活性要略高于Co-ZSM5,具有更佳的催化性能.通过量子化学计算揭示了Mn-ZSM5及Co-ZSM5对NO氧化的催化反应机理,为过渡态金属催化氧化NO的进一步研究提供了理论参考.

Due to the importance of the catalytic oxidation of nitric oxide in the field of NOx denitration, the detailed mechanism of oxidation of nitric oxide catalyzed by ZSM5-supported Mn, Co catalyst was investigated in this paper by employing the density functional theory of quantum chemistry. The reactants, transition states, intermediates and products along all the relevant reactions were calculated and optimized by UB3LYP//SDD method. And also, based on the analysis of the reaction pathways, the activate energies of the reactions were calculated and obtained. Results showed that the activate energies of reactions catalyzed by ZSMS-supported Mn/ Co （71.1 kJ/mol or 80. 6 kJ/mol） were quite lower than that of direct oxidation of nitric oxide（135.5 kJ/mol）, which indicated that ZSMS-supported Mn/Co has obvious catalytic effect; and furthermore, Mn-ZSM5 was showed as a more efficient catalyst than Co-ZSM5. The theoretical investigation in this paper could supply the theoretical reference for the further research of catalytic oxidation of nitric oxide.