碱金属对煤焦异相还原NO的催化机理：量子化学研究

针对碱金属催化煤焦异相还原NO的相关反应，采用密度泛函计算方法UB3LYP/6 31G(d)优化获得了反应通道上所有驻点的几何构型，得到了微观反应进程.采用高精度能量计算方法QCISD(T)/6 311G(d,p)计算得到了所研究反应的活化能，并结合经典过渡态理论，计算得到反应速率常数，拟合出阿仑尼乌斯表达式.通过比较各反应的活化能和反应速率常数发现，碱金属的存在使煤焦异相还原NO的活化能大大降低，提高了反应速率，起到催化作用；碱金属的活泼性越强，则其与NO反应的活化能越低，对煤焦异相还原NO的催化性能越好.

Catalytic mechanism of alkali metal on NO heterogeneous reduction by char:quantum chemistry study

The reactions about the catalytic mechanism of alkali metal on NO reduction by char were investigated by quantum chemistry.The geometry optimizations of reactants,transition states,intermediates and products of the reactions were made by using density functional theory(DFT),UB3LYP,at 6-31G(d) basis function level,then the microcosmic reaction pathways were investigated.Based on the analysis of reaction pathways,molecule energies were calculated by a high-level ab initio method,QCISD(T)/6-311G(d,p),and corrected with zero point energy.The activation energies were worked out,and the reaction rate constants were calculated from transition state theory(TST).Comparisons of the activation energies and the reaction rate constants show that the presence of alkali metal largely lowers the activation energies and quickens the reaction rate,adequately achieving the catalytic effect of NO reduction by char.With the increase of alkali metal reactivity,the reaction activation energy of alkali metal and NO decreases and the catalytic effect of NO reduction by char is strengthened.