Abstract

SIRI, G. J.; BERTOLINI, G. R.  and  FERRETTI, O. A.. Preferential oxidation of CO in presence of H₂ behavior OF PtSn/γ -Al₂O₃ catalysts modified by K or Ba. Lat. Am. appl. res. [online]. 2007, vol.37, n.4, pp.275-281. ISSN 0327-0793.

The behavior of catalysts based on Pt/γ-Al₂O₃ is analyzed in the CO oxidation reaction. Experiments were performed in the temperature range between 50°C and 250°C with a feed H₂ rich, and a concentration of 1% CO and 0.6% O₂ Catalysts studied were: monometallic Pt/γ-Al₂O₃, bimetallic PtSn/γ-Al₂O₃ with a ratio Sn/Pt=1.6 at/at and two catalysts prepared by modification of the last one with K or Ba. The catalyst that showed maximum activity and selectivity levels is the PtSnK/γ-Al₂O₃. The tin addition increases the activity which allows the reaction to occur at lower temperatures due to the decrease in the CO-Pt interaction. The addition of K or Ba produces a subsequent improvement with respect to the CO oxidation temperature, which leads to a selectivity increase. The selectivity of the CO oxidation passes through a maximum value as a function of the temperature. This maximum is explained by the importance acquired by the reverse of water gas shift reaction at temperatures near 200ºC.

Keywords : Preferential Oxidation; Hydrogen Purification; PtSn/γ -Al₂O₃.

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