Artículo
Toward an Understanding of Selective Alkyne Hydrogenation on Ceria: On the Impact of O Vacancies on H 2 Interaction with CeO 2 (111)
Werner, Kristin; Weng, Xuefei; Calaza, Florencia Carolina
; Sterrer, Martin; Kropp, Thomas; Paier, Joachim; Sauer, Joachim; Wilde, Markus; Fukutani, Katsuyuki; Shaikhutdinov, Shamil; Freund, Hans-Joachim
Fecha de publicación:
11/2017
Editorial:
American Chemical Society
Revista:
Journal of the American Chemical Society
ISSN:
0002-7863
Idioma:
Inglés
Tipo de recurso:
Artículo publicado
Clasificación temática:
Resumen
Ceria (CeO2) has recently been found to be a promising catalyst in the selective hydrogenation of alkynes to alkenes. This reaction occurs primarily on highly dispersed metal catalysts, but rarely on oxide surfaces. The origin of the outstanding activity and selectivity observed on CeO2 remains unclear. In this work, we show that one key aspect of the hydrogenation reaction—the interaction of hydrogen with the oxide—depends strongly on the presence of O vacancies within CeO2. Through infrared reflection absorption spectroscopy on well-ordered CeO2(111) thin films and density functional theory (DFT) calculations, we show that the preferred heterolytic dissociation of molecular hydrogen on CeO2(111) requires H2 pressures in the mbar regime. Hydrogen depth profiling with nuclear reaction analysis indicates that H species stay on the surface of stoichiometric CeO2(111) films, whereas H incorporates as a volatile species into the volume of partially reduced CeO2–x(111) thin films (x ∼ 1.8–1.9). Complementary DFT calculations demonstrate that oxygen vacancies facilitate H incorporation below the surface and that they are the key to the stabilization of hydridic H species in the volume of reduced ceria.
Palabras clave:
Ceria
,
Hydrogenation
,
Hydride
,
Heterolytic
Archivos asociados
Licencia
Identificadores
Colecciones
Articulos(INTEC)
Articulos de INST.DE DES.TECNOL.PARA LA IND.QUIMICA (I)
Articulos de INST.DE DES.TECNOL.PARA LA IND.QUIMICA (I)
Citación
Wilde, Markus; Shaikhutdinov, Shamil; Sauer, Joachim; Werner, Kristin; Sterrer, Martin; Weng, Xuefei; et al.; Toward an Understanding of Selective Alkyne Hydrogenation on Ceria: On the Impact of O Vacancies on H 2 Interaction with CeO 2 (111); American Chemical Society; Journal of the American Chemical Society; 139; 48; 11-2017; 17608-17616
Compartir
Altmétricas