CH4 dissociation on NiCo (1 1 1) surface: A first-principles study
CH4 dissociation on NiCo (1 1 1) surface: A first-principles study
复制标题
DOI：
10.1016/j.apsusc.2011.05.073
复制
发表时间：
2011-08
影响因子：
6.7
通讯作者：
Hongyan Liu;Riguang Zhang;R. Yan;Baojun Wang;K. Xie
中科院分区：
文献类型：
--
作者：
Hongyan Liu;Riguang Zhang;R. Yan;Baojun Wang;K. Xie
采用密度泛函理论方法研究了有序 NiCo 合金 (1 1 1) 面上 CHx(x= 0–4) 的吸附以及 CHx(x= 1–4) 的解离。结果与纯 Ni (1 1 1) 表面上获得的结果进行了比较。结果表明，与纯 Ni (1 1 1) 相比，NiCo (1 1 1) 上的 C 和 CH 的吸附能降低，而 CH3 的吸附能增加。此外，在NiCo(1 1 1)上，CHx的解离不是在Ni的顶部，而是在Co的顶部。CH4解离的限速步骤被认为是NiCo(1 1 1)上脱氢的第一步，而它是Ni(1 1 1)上脱氢的第四步。此外，Ni (1 1 1) 上速率决定步骤中的激活势垒比 NiCo (1 1 1) 上的激活势垒略高 0.07 eV。从以上结果可以看出，尽管 C 原子的吸附能比 Ni (1 1 1) 上的吸附能略有下降，但 NiCo (1 1 1) 上很容易形成碳。
A density-functional theory method has been conducted to investigate the adsorption of CHx(x= 0–4) as well as the dissociation of CHx(x= 1–4) on (1 1 1) facets of ordered NiCo alloy. The results have been compared with those obtained on pure Ni (1 1 1) surface. It shows that the adsorption energies of C and CH are decreased while it is increased for CH3on NiCo (1 1 1) compared to those on pure Ni (1 1 1). Furthermore, on NiCo (1 1 1), dissociation of CHxprefers not to the top of Ni, but to the top of Co. The rate-determining step for CH4dissociation is considered as the first step of dehydrogenation on NiCo (1 1 1), while it is the fourth step of dehydrogenation on Ni (1 1 1). Furthermore, the activation barrier in rate-determining step is slightly higher by 0.07 eV on Ni (1 1 1) than that on NiCo (1 1 1). From above results, it is important to point out that carbon is easy to form on NiCo (1 1 1) although the adsorption energy of C atom is slightly decreased compared to that on Ni (1 1 1).