INVESTIGADORES
AMADEO Norma Elvira
artículos
Título:
The influence of Mg on the carbon adsorption on Ni(100). A DFT study
Autor/es:
HERNAN MILBERG, ; ALFREDO JUAN; NORMA AMADEO; BEATRIZ IRIGOYEN
Revista:
JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL
Editorial:
ELSEVIER SCIENCE BV
Referencias:
Año: 2010 vol. 315 p. 171 - 177
ISSN:
1381-1169
Resumen:
In this work, we performed density functional theory (DFT) calculations to study carbon adsorption on
the Ni(1 0 0) surface and absorption in the bulk of nickel-based catalysts. The ideal catalyst surface was
modeled as a five-layer Ni(1 0 0) slab. We also studied the influence of magnesium, considered as an
atomic substitutional impurity, on carbon adsorption and migration into the bulk.
To study the effect of Mg on the structure of Ni-based catalysts, we replaced a Ni atom by a Mg atom,
on the surface and also in the bulk. Then, we relaxed the Mg and Ni positions. Our results showed that Ni
atoms were pushed away from Mg.Wealso performed energy calculations to evaluate carbon interactions
on different preferential sites of the Ni-slab, and also the effect of Mg atom on these deposition processes.
The calculations showed that carbon adsorption on the bare Ni(1 0 0) surface was more favorable than
deposition on this surface doped with magnesium. Our results also indicated that Mg could improve the
interaction of surface-adsorbed carbon with gas phase oxygen, leading to the formation of a CO precursor
species. In this way, magnesium promotes Ni-based catalysts hindering the surface from attaining a high
carbon coverage, and thus making difficult the formation of carbon agglomerates and carbon whiskers.
We also considered the effect of Ca in the CO interaction on the metal surface.
.