DFT studies of dry reforming of methane on Ni catalyst
DFT studies of dry reforming of methane on Ni catalyst
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DOI：
10.1016/j.cattod.2009.08.022
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发表时间：
2009-11
期刊：
影响因子：
5.3
通讯作者：
Yian Zhu;De Chen;Xinggui Zhou;W. Yuan
中科院分区：
文献类型：
--
作者：
Yian Zhu;De Chen;Xinggui Zhou;W. Yuan
采用基于密度泛函理论(DFT)的第一性原理计算方法，研究了干甲烷在Ni(111)面上的重整反应机理。用二聚体方法确定了参与该过程的物种的最有利的吸附构型，并探索了所有可能的基本步骤的过渡态。然后，通过计入零点能修正、热能修正和熵效应，计算了973.15K时的相关热力学性质。结果表明，CO2主要通过直接解离途径生成CO和O，原子O是CHx中间体的主要氧化剂。基于这一信息，构建了两条主要的反应路径，因为CH和C都可能被氧化。反应网络始于CO2和CH4的解离，然后生成的CH和C被原子O氧化生成CHO和CO，然后CHO分解生成CO和H2。对于这两条反应途径，在本研究条件下，氧化步骤决定了总的反应速度，而CH4解离在较低温度下是限速步骤。
First-principles calculations based on density functional theory (DFT) have been used to investigate the reaction mechanism of dry methane reforming on Ni(111). The most energetically favorable adsorption configurations of the species involved in this process are identified and the transition states for all the possible elementary steps are explored by the dimer method. Then, the related thermodynamic properties at 973.15K are calculated by including the zero-point energy correction, thermal energy correction and entropic effect. It is found that CO2dissociates via a direct pathway to produce CO and O dominantly, and atomic O is revealed to be the primary oxidant of CHxintermediates. Based on this information, two dominant reaction pathways are constructed as both the CH and C oxidation are found to be likely. The reaction network begins with the dissociation of CO2and CH4, and then the generated CH and C are oxidized by atomic O to produce CHO and CO, followed by the CHO decomposition to finally generate CO and H2. As for these two reaction pathways, the oxidation step is predicted to determine the overall reaction rate under the current investigated conditions, while the CH4dissociation is found to be the rate-limiting step at lower temperatures.