Complete oxidation of methane and carbon monoxide on supported palladium and platinum catalysts

Abstract

Palladium and platinum supported by CeO₂, ZrO₂ and AI₂O₃ have been prepared by conventional impregnation method. The effect of support on catalytic activity on oxidation of CO and methane has been studied. The activity of the supported Pd catalyst is much higher than that of the supported Pt catalyst. The catalytic activity depends on the nature of the support; the sequence for supported Pd and Pt catalyst being CeO₂ > ZrO₂ > Al₂O₃. For both CO and methane oxidation, Pd/CeO₂ shows highest activity with a light-off temperature at 45° and 310°C respectively, with no apparent decay. This is mostly due to the superoxide species over CeO₂ Pd/ZrO₂, Pd/AI₂O₃ and Pt/CeO₂ catalysts exhibit apparent deactivation. The heat-stability of Pd/CeO₂ is inferior to Pd/AI₂O₃ catalyst, but the oxidation activity of Pd/CeO₂), catalyst for CO and methane is higher than that of Pd/Al₂O₃, after calcination at 1200°C for 4h.