Methane dissociation on the steps and terraces of Pt(211) resolved by quantum state and impact site.
J Chem Phys
; 148(1): 014701, 2018 Jan 07.
Article
em En
| MEDLINE
| ID: mdl-29306302
ABSTRACT
Methane dissociation on the step and terrace sites of a Pt(211) single crystal was studied by reflection absorption infrared spectroscopy (RAIRS) at a surface temperature of 120 K. The C-H stretch RAIRS signal of the chemisorbed methyl product species was used to distinguish between adsorption on step and terrace sites allowing methyl uptake to be monitored as a function of incident kinetic energy for both sites. Our results indicate a direct dissociation mechanism on both sites with higher reactivity on steps than on terraces consistent with a difference in an activation barrier height of at least 30 kJ/mol. State-specific preparation of incident CH4 with one quantum of antisymmetric (ν3) stretch vibration further increases the CH4 reactivity enabling comparison between translational and vibrational activation on both steps and terraces. The reaction is modeled with first principles quantum theory that accurately describes dissociative chemisorption at different sites on the surface.
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01-internacional
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MEDLINE
Idioma:
En
Ano de publicação:
2018
Tipo de documento:
Article