In situ EXAFS and FTIR studies of the promotion behavior of Pt-Nb2O5/Al2O3 catalysts during the preferential oxidation of CO

S. Guerrero, J. T. Miller, A. J. Kropf, E. E. Wolf*

*Autor correspondiente de este trabajo

Resultado de la investigación: Contribución a una revistaArtículorevisión exhaustiva

35 Citas (Scopus)

Resumen

The promotional effect of Nb to Pt/Al2O3 supported catalysts during the preferential oxidation of CO (PROX) was studied using various spectroscopic techniques. Addition of small amounts of Nb (<5%) stabilizes 40% of the loaded platinum as Pt2+, which remains oxidized even after reduction treatments. This Nb-promoted catalyst is very active and selective for the PROX reaction. On Pt/Nb2O5 and at high Nb loading for the Pt/Nb/Al2O3 catalysts, the selectivity to CO2 decreases and the selectivity for H2 oxidation increases opposite to the selectivity observed at low Nb loadings. The increase CO2 selectivity due to Nb promotion is ascribed to the inhibition of CO at low temperature which decreases hydrogen oxidation. Operando FTIR results indicate the presence of adsorbed CO as well as carbonates, bicarbonates and formates during the PROX reaction. An IR band at 968 cm-1 indicates the presence of Nb{double bond, long}O moieties at low Nb loadings. At higher Nb loadings, IR suggests the formation of three-dimensional Nb2O5 aggregates. The surface of the Nb containing catalysts is complex containing reduced and oxidized Pt which is modified by NbOx species either surrounding the Pt crystallites or decorating them.

Idioma originalInglés
Páginas (desde-hasta)102-110
Número de páginas9
PublicaciónJournal of Catalysis
Volumen262
N.º1
DOI
EstadoPublicada - 15 feb. 2009
Publicado de forma externa

Huella

Profundice en los temas de investigación de 'In situ EXAFS and FTIR studies of the promotion behavior of Pt-Nb2O5/Al2O3 catalysts during the preferential oxidation of CO'. En conjunto forman una huella única.

Citar esto