Produção Nacional
Revisado por pares
DFT Study of the Water–Gas Shift Reaction and Coke Formation on Ni(111) and Ni(211) Surfaces
2012; American Chemical Society; Volume: 116; Issue: 38 Linguagem: Inglês
10.1021/jp302488f
ISSN1932-7455
AutoresRafael C. Catapan, Amir Antônio Martins Oliveira, Ying Chen, Dionisios G. Vlachos,
Tópico(s)Ammonia Synthesis and Nitrogen Reduction
ResumoWe report for the first time results of a systematic density functional theory (DFT) study of the water-gas shift (WGS) reaction and coke formation pathways on Ni(111) and Ni(211) surfaces, consisting of 21 elementary-like steps and 12 surface species. Brønsted–Evans–Polanyi correlations are proposed for dehydrogenation and C–O bond breaking reactions on flat and stepped surfaces. The DFT results suggest that the flat surface is slightly more active for the WGS reaction, which occurs mainly via the carboxyl pathway with the CO* + OH* ⇌ COOH*+* as the rate determining step. On the stepped surface, beyond the carboxyl pathway, the DFT energetics indicates that a parallel route via formate and formyl intermediates is favored. Ni(111) has a much lower activity for C–O bond breaking, and thus, flat surfaces are less susceptible to deactivation by coke.
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