CO OXIDATION OVER PD/SNO2 CATALYST

Oxidation of CO over the surface of SnO2 and Pd/SnO2 catalysts has been investigated with a view to understand the role of Pd metal particles which are known to improve the catalytic activity. The reaction occurs through the incorporation of lattice oxygen and an oxidized surface of the catalyst facilitates the CO oxidation. For Pd/SnO2 Significant CO oxidation occurs even at room temperature as monitored by CO pulse injection technique. Disproportionation of CO into CO2 and carbon has been observed in the region 350 K less-than-or-equal-to T less-than-or-equal-to 425 K. From Sn-119 Mossbauer investigations the existence of Sn2+ species in the support matrix has been observed and its extent is affected by Pd incorporation. The effect of oxygen and/or hydrogen pretreatment of Pd/SnO2 catalyst at different temperatures on its catalytic activity has been discussed.