The effects of CeO2 on the activity and stability of Pt supported catalysts for methane reforming, as addressed by in situ temperature resolved XAFS and TEM analysis

Autor: J.C.S. Araújo, Fabio B. Noronha, Daniela Zanchet, José Maria C. Bueno, A.P. Ferreira, Eduardo Falabella Souza-Aguiar, J.W.C. Liberatori
Rok vydání: 2009
Předmět:
Zdroj: Journal of Catalysis. 263:335-344
ISSN: 0021-9517
Popis: The effects of Ce as a promoter on the activity and stability of Pt/Al 2 O 3 and Pt/CeO 2 –Al 2 O 3 catalysts for autothermal reforming and partial oxidation of methane (POM) were investigated. The Pt/CeO 2 –Al 2 O 3 catalyst exhibited higher activity and stability than the Pt/Al 2 O 3 catalyst. Analysis by in situ X-ray absorption spectroscopy under POM conditions reveals that Pt is reduced by heating the catalysts to about 730 K. The overall first-shell coordination numbers suggest changes in Pt cluster morphology with increasing temperature. Transmission electron microscopy showed strong Pt agglomeration with time on stream for the Pt/Al 2 O 3 catalyst. The higher stability of the Pt/CeO 2 –Al 2 O 3 catalyst was attributed to a combination of different properties: (i) hindrance of carbon deposition on the Pt surface for a reactor fed with low H 2 O/CH 4 ratio; (ii) interaction of Pt O Ce species in the presence of oxygen, inhibiting vapor and diffusion transport of PtO 2 and mainly, (iii) thermal stability of the support, which prevents the loss of surface area, and consequently the sintering of the Pt.
Databáze: OpenAIRE
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