CH4 dissociation on NiCo (1 1 1) surface: A first-principles study |
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| Authors: | Hongyan Liu Riguang ZhangRuixia Yan Baojun Wang Kechang Xie |
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| Institution: | a Key Laboratory of Coal Science and Technology of Ministry of Education and Shanxi Province, Taiyuan University of Technology, Taiyuan 030024, China
b College of Chemistry and Chemical Engineering, Shanxi Datong University, Datong 037009, Shanxi Province, China |
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| Abstract: | 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 CH3 on NiCo (1 1 1) compared to those on pure Ni (1 1 1). Furthermore, on NiCo (1 1 1), dissociation of CHx prefers not to the top of Ni, but to the top of Co. The rate-determining step for CH4 dissociation 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). |
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| Keywords: | Alloy Dissociation Adsorption Reaction barrier Density functional calculation |
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