Syngas production by partial oxidation of methane over Pt/CeZrO2/Al2O3 catalysts

In this study, we evaluated the effect of ceria-zirconia content on the performance of Pt/ x% CeZrO2/Al2O3 (x = 0-40 wt.%) during partial oxidation of methane. X-ray diffraction results indicated that, for samples containing 10 and 20 wt.% of CeZrO2, there was the formation of a homogeneous solid solution between ceria and zirconia. On the other hand, for Pt/30% CeZrO2/Al2O3, there was the formation of a ceria rich phase and a zirconia rich phase whereas a ceria rich phase and an isolated zirconia phase were detected for Pt/40% CeZrO2/Al2O3. Catalytic tests showed that Pt/Al2O3 exhibited a significant deactivation, while Pt/10% CeZrO2/Al2O3 and Pt/20% CeZrO2/Al2O3 practically did not loose their activity after 24 h. A deactivation was detected for Pt/30% CeZrO2/Al2O3 and Pt/40% CeZrO2/Al2O3. The higher stability of the Pt/10% CeZrO2/Al2O3 and Pt/20% CeZrO2/Al2O3 catalysts was attributed to the high reducibility and consequently the high oxygen mobility of the homogeneous solid solution formed, which promoted the mechanism of carbon removal from the metallic particle. (C) 2011 Elsevier B.V. All rights reserved.