Resumo

PADILLA, J.M. et al. Toluene combustion on Pd and Pt catalysts supported on γ-Al₂O₃ and γ-Al₂O₃-Ce. Rev. Mex. Ing. Quím [online]. 2013, vol.12, n.1, pp.73-83. ISSN 1665-2738.

This work reports the study of the catalytic oxidation of toluene (1400 ppm) on Pd and Pt catalysts supported over alumina promoted with 1 and 10 wt% Ce. Catalysts were characterized by: physical adsorption N₂ (BET), XRD, UV-VIS, FTIR of adsorbed pyridine, FTIR od the CO adsorption, XPS and TPO. The results showed a decrease in the number of acid sites with the loading of Ce in the catalyst. It was observed higher dispersion on Pd than on Pt catalysts. For Pt catalysts only Pt⁰ species was detected while in palladium catalysts Pd⁰ and Pd²⁺ species were observed. For both series of catalysts total combustion was reached on the catalysts containing 1% of Ce, Pt/ACe1, and Pd/ACe1 catalysts, at 300^oC. For Pd catalysts the maximum in activity depended on the redox optimal ratio (Ce³⁺/ Ce⁴⁺, Pd⁰/ Pd²⁺) ant the activation time for the calalyst was important. The catalytic combustion of toluene on Pt was favored on reduced surface through a process of demethylation. The depot of carbon on catalyst decreased with Ce contents due to redox properties of the cerium oxide.

Palavras-chave : Pd/γ-Al₂O₃-Ce, Pt/γ-Al₂O₃-Ce; toluene combustion; XPS of Pd and Pt; depot of carbon; redox species.

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