甲烷在Cu表面解离的密度泛函理论研究

Density Functional Theoretical Study of Methane Dissociation on Cu Surface

对甲烷在Cu(100)、Cu(110)、Cu(111)表面发生CH_4→CH_3+H的解离反应进行研究。基于密度泛函理论(DFT),结合平板模型,通过优化反应物、过渡态和产物的几何构型,获得反应路径上的活化能垒等参数。结果表明:(1)甲烷在Cu(110)面上解离时活化能垒较低;(2)当Cu催化剂的基底弛豫时可有效降低甲烷在上面分解的活化能垒,C-H键长和∠H-C-H角度也发生变化。甲烷在Cu(110)表面上发生CH_4→CH_3+H的分解过程相比Cu(100)和Cu(111)更为有利。

The decomposition process of methane on single metal Cu（100）, Cu（110） and Cu（111） surfaces are studied, which happens CH4→CH3＋H. By optimizing the pyrolysis process of reactant, transition state and product＇s geometry, the activation barriers of the reaction path are also obtained. The results show that： （1） The lowest activation barrier is Cu（110） surface; （2） When the catalysts are relaxed, the activation barrier of methane dissociation is significantly reduced; what＇s more, the length of C-H and the angle of ∠H-C-H are also changed. The decomposition process of CH4→CH3＋H on the Cu（110） surface is better than Cu（100） and Cu（111）.