On the promoting effect of the addition of CexZr1−xO2 to palladium based alumina catalysts for methanol deep oxidation

• Pd/Al2O3 and Pd/Al2O3-50 wt% CexZr1−xO2 were studied in deep oxidation of methanol.
• The Pd/Al–Ce0.3Zr0.7O2 catalyst exhibits the highest activity.
• A strong interaction between noble metal and Al–Ce0.3Zr0.7O2 is found.
• The high redox property and more active sites at low temperature are crucial.
• Textural property, activated surface oxygen and basicity also affect the activity.

A series of Al2O3-50 wt% CexZr1−xO2 (x = 0.1, 0.3, 0.5, 0.7 and 0.9) mixed oxides and pure alumina as supports were prepared by conversional coprecipitation. The corresponding Pd catalysts were investigated in deep oxidation of methanol and characterized by BET, H2-TPR, O2-TPD, CO2-TPD and CH3OH-TPSR techniques. The catalytic tests reveal that Pd/Al–Ce0.3Zr0.7O2 exhibits the best catalytic activity. It is mainly attributed to a strong interaction between noble metal and support in the Pd/Al–Ce0.3Zr0.7O2 catalyst, resulting in more reducible species and active sites at low temperature. Additionally, the relatively better textural property, more activated surface oxygen and more strong basic sites are favorable to the deep methanol oxidation.

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