Low-temperature oxidation of methane on Pd-Sn/ZrO2 catalysts

• Sn oxide species adsorb O2 acting as an oxygen reservoir.
• Pd particle size increases with calcination temperature and Sn content.
• The presence of Sn on Pd based catalysts promotes the methane oxidation reaction.
• The Sn effects on Pd-Sn-containing catalysts decrease in solids calcined at 1100 °C.

Pd/ZrO2, Pd-Sn/ZrO2 and Sn/ZrO2 were prepared by incipient wetness using Pd(NO3)2·XH2O and SnC4H4O6·XH2O as precursors, dried and calcined in static air at 500 °C, 800 °C or 1100 °C. The influence of Sn species in the oxygen storage capacity of the catalysts, distribution of Pd particle sizes and CH4 oxidation reaction were investigated. Pd particle size was larger on Sn-containing catalysts and showed lower mobility than those in the absence of Sn. Sn oxide species act as an oxygen reservoir that are easily transferred to Pd surfaces promoting the oxidation reaction of methane. For Pd-Sn-containing solids calcined at 1100 °C, the contribution of Sn in the CH4 oxidation reaction is negligible.

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