Influence of the tensile strain on CH4 dissociation on Cu(100) surface: A theoretical study
Influence of the tensile strain on CH4 dissociation on Cu(100) surface: A theoretical study
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拉伸应变对 Cu(100) 表面 CH4 解离的影响：理论研究
DOI：
10.1016/j.apsusc.2015.11.073
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发表时间：
2016
影响因子：
6.7
通讯作者：
Wu Zhijian
中科院分区：
文献类型：
--
作者：
He Feng;Li Kai;Xie Guangyou;Wang Ying;Jiao Menggai;Tang Hao;Wu Zhijian
由于催化剂和基材（例如本工作中的 Cu/MgO）之间的晶格失配，催化剂表面广泛存在拉伸应变。因此，研究拉伸应变对催化性能的影响非常重要。在本研究中，我们通过考虑拉伸应变研究了 Cu(1 0 0) 表面上的 CH4 解离。我们的结果表明，与无应变的 Cu(1 0 0) 表面相比，应变表面上解离物种 CHx(x= 0⿿3) 和 H 吸附的最稳定位点保持不变。表面应变增强了CHx(x=0⿿3)的吸附，同时减弱了H的吸附。电子能垒最大的 CH4 解离基元反应从无应变表面上的 CH ⿿ C + H 变为应变表面上的 CH4⿿ CH3+ H（应变等于或大于 3%），这与实验观察到的 CH4 解离成 CH3 和 H 是最困难的反应一致。拉伸应变加速C迁移，但对C聚合没有明显影响。 DFT 计算和微动力学模型都表明应变阻碍了 Cu(1 0 0) 表面上的 CH4 解离过程。 CH4 解离速率敏感地取决于表面拉伸应变的大小。
Tensile strain is widespread on the catalyst surface due to the lattice mismatch between the catalyst and substrate, such as Cu/MgO in this work. Thus, it is important to investigate the influence of tensile strain on the catalytic properties. In this study, we have investigated the CH4dissociation on Cu(1 0 0) surface by considering the tensile strain. Our results showed that compared with the unstrained Cu(1 0 0) surface, the most stable sites for dissociation species CHx(x= 0⿿3) and H adsorption on strained surface remain unchanged. The surface strain strengthens CHx(x= 0⿿3) adsorption, while weakens H adsorption. The elementary reaction for CH4dissociation with the largest electronic energy barrier changes from CH ⿿ C + H on the unstrained surface to CH4⿿ CH3+ H on the strained surface (for strain equal to and larger than 3%), in agreement with the experimental observation that CH4dissociation into CH3and H is the most difficult reaction. The tensile strain accelerates C migration while has no obvious influence for C polymerization. Both DFT calculations and microkinetic model demonstrated that the strain hinders the CH4dissociation process on Cu(1 0 0) surface. CH4dissociation rate depends sensitively on the magnitude of the surface tensile strain.