Reversible hydrogenation of surface N atoms to form NH on Pt(111).
J Phys Chem B
; 109(7): 2828-35, 2005 Feb 24.
Article
en En
| MEDLINE
| ID: mdl-16851294
The formation and dissociation chemistry of the NH species on Pt(111) was characterized with reflection absorption infrared spectroscopy and temperature programmed desorption. Irradiation of a chemisorbed bilayer of ammonia with a 100 eV electron beam at 85 K leads to a mixture of NH, N, and H on the surface. Annealing to temperatures in the range of 200-300 K leads to reaction of N and H to form additional NH. The NH species has an intense and narrow NH stretch peak at 3320 cm(-1), while no peak due to the PtNH bend is observed above 800 cm(-1). The NH species is stable up to a temperature of approximately 400 K. The surface N atoms produced from NH dissociation are readily hydrogenated back to NH by exposure of the surface to H2. However, NH cannot be further hydrogenated to generate adsorbed NH2 or to NH3 under the conditions used here. Exposure of the NH/Pt(111) surface to D2 at 380 K produces the ND species. Comparison with the results of density functional theory calculations based on small Pt clusters indicates that NH occupies three-fold hollow sites with the molecular axis perpendicular to the surface.
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Colección:
01-internacional
Base de datos:
MEDLINE
Idioma:
En
Revista:
J Phys Chem B
Asunto de la revista:
QUIMICA
Año:
2005
Tipo del documento:
Article
País de afiliación:
Estados Unidos
Pais de publicación:
Estados Unidos