碳质表面异相还原NO2的反应机理

基于量子化学密度泛函理论（DFT），研究了碳质表面异相还原NO₂的反应机理，针对Zigzag与Armchair两种碳质表面，采用M06-2X方法与6-311G （d）基组联用，优化得到了不同反应路径下所有驻点的几何构型与能量，并对各路径进行了热力学与动力学分析，重点探究了CO在NO₂异相还原反应中的作用规律，同时考察了碳质表面与反应温度对异相反应的影响。计算结果表明，NO₂在碳质表面的异相还原过程主要分为两个阶段，即NO₂还原阶段与碳氧化物释放阶段。通过对比无CO分子参与的反应可知，参与反应的CO分子可以降低各阶段的反应能垒并且加快各阶段的反应速率；CO分子存在时，NO₂还原阶段的反应能垒被降低，促进了NO₂还原成NO的异相反应过程，同时参与反应的CO分子与碳质表面剩余氧原子结合，形成CO₂分子并释放，使碳氧化物释放阶段的反应能垒降低，从而促进了整体还原反应的进行。此外，与Armchair型相比，基于Zigzag型碳质表面的NO₂异相还原反应能垒更低且反应速率更快，说明NO₂异相还原反应更容易在Zigzag型碳质表面进行。最后，由反应动力学分析可知，随着温度上升，各阶段的反应速率均增大，说明提高温度对碳质表面的NO₂异相还原能够起到促进作用。

Reaction mechanism of heterogeneous reduction of NO2 on carbonaceous surface

Based on the quantum chemical density functional theory(DFT), the mechanism of heterogeneous reduction of NO₂ on carbonaceous surface was studied. For zigzag and armchair carbonaceous surfaces, M06-2X method and 6-311G(d) basis set were used to optimize the geometry configuration and energy of all stagnation points under different reaction paths,and the reaction paths were analyzed and compared from thermodynamics and kinetics. The role of CO in the heterogeneous reduction of NO₂ was deeply investigated,and the effects of carbon surface and reaction temperature on the heterogeneous reaction were also investigated. The results show that the heterogeneous reduction process of NO₂ on the carbon surface can be divided into two stages: the reduction stage of NO₂ and the desorption stage of carbon oxide. By comparing the reactions without CO molecules, it can be seen that the CO molecules involved in the reaction can reduce the reaction energy barrier of each stage and accelerate the reaction rate of each stage. In the presence of CO molecule, the reaction energy barrier at the reduction stage of NO₂ is reduced, which promotes the heterogeneous reaction process of NO₂ reduction to NO. CO molecules participating in the reaction can combine with the residual oxygen atoms on the surface to form and release CO₂ molecules, which reduces the reaction energy barrier in the release stage of carbon oxides, thus promoting the overall reduction reaction. In addition, the energy barrier of NO₂ heterogeneous reduction reaction on zigzag surface is lower and the reaction rate is faster than that on armchair surface, which indicates that the heterogeneous reduction reaction of NO₂ is easier on Zigzag carbonaceous surface. Finally, the reaction kinetics analysis shows that the reaction rate of each stage increases with the increase of temperature, which indicates that increasing temperature can promote the heterogeneous reduction of NO₂ on the carbonaceous surface.