First-principles Study of Methane Dehydrogenation on a Bimetallic Cu/Ni(111) Surface
We present density-functional theory calculations of the dehydrogenation of methane and CHx (x =1–3) on a Cu/Ni(111) surface, where Cu atoms are substituted on the Ni surface at a coverage of 1/4 monolayer. As compared to the results on other metal surfaces, including Ni(111), a similar activation mechanism with different energetics is found for the successive dehydrogenation of CH4 on the Cu/Ni(111) surface. In particular, the activation energy barrier (Eact) for CH→C+H is found to be 1.8 times larger than that on Ni(111), while Eact for CH4→CH3+H is 1.3 times larger. Considering the proven beneficial effect of Cu observed in the experimental systems, our findings reveal that the relative Eact in the successive dehydrogenation of CH4 plays a key role in impeding carbon formation during the industrial steam reforming of methane. Our calculations also indicate that previous scaling relationships of the adsorption energy (Eads) for CHx (x=1–3) and carbon on pure metals also hold for several Ni(111)-based alloy systems.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 1006313
- Journal Information:
- Journal of Chemical Physics, 131(17):174702/1-174702/11, Vol. 131, Issue 17; ISSN 0021-9606
- Country of Publication:
- United States
- Language:
- English
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