为了研究燃烧过程中氮氧化物的转化特性，采用M06-2X/6-311G(d)密度泛函理论研究了CO还原N2O的均相和异相反应过程，并通过计算热力学与动力学参数分析其反应机理。结果表明：CO均相还原N2O的活化能为216.93 kJ/mol，煤焦异相催化CO还原N2O反应的活化能为133.06 kJ/mol;CO还原N2O的均相和异相反应过程差异较大，CO与N2O的均相还原反应速率决定反应步是R→TS1,而异相还原反应速率决定反应步是IM→TS,在298.15~1 800 K内，异相还原的反应速率始终大于均相反应速率;煤焦表面可以为N2O的还原提供反应位点，对气体之间的反应具有催化作用。

In order to explore the transformation characteristics of nitrogen oxides during coal combustion,the reaction mechanism of homogeneous and charcatalyzed heterogeneous N2O reduction with CO were investigated through density functional theory at the M062X/6311G(d) level.Thermodynamic and kinetic parameters were analyzed to study the reaction mechanism.Results show that the activation energy of homogeneous N2O reduction is 216.93 kJ/mol,which is much larger than that of charcatalyzed heterogeneous N2O reduction (133.06 kJ/mol).Homogeneous N2O reduction process has three transition states,while only one is found in heterogeneous N2O reduction.R→TS1 and IM→TS are the reaction rate determining step in homogeneous and heterogeneous N2O reduction process,respectively.The reaction rate of heterogeneous N2O reduction is higher than that of homogeneous N2O reduction at 298~1800 K.Char surface can provide reaction sites,and it can effectively promote the N2O reduction.

TQ530.2

辽宁省自然科学基金（2017054067）；国家电网公司科技项目（SGLNSY00FZTS1801309）