Characterization and Activity of Pd-Ir Catalysts in CO and C3H6 Oxidation Under Stoichiometric Conditions

摘要

Bimetallic Pd-Ir catalysts based on halogen free precursors supported on alumina and La-stabilized alumina were prepared and characterized. The influence of iridium co-metal loading on activity of supported palladium catalysts in CO and C3H6 oxidation was studied. In addition, the effect of thermal aging on the catalytic activity was discussed. The powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy combined with energy dispersive X-ray spectroscopy, thermogravimetric analysis were used for characterization of the catalysts. The catalytic activity of prepared catalysts was determined based on conversion of CO and C3H6 under stoichiometric condition. The activity tests showed that bimetallic catalyst with Pd:Ir molar ratio of 1.00:0.18 on both support materials has the lowest light-off temperature difference between the fresh and aged catalysts in CO and C3H6 oxidation. However, high Ir loading improved the activity of the catalysts only, if La-stabilized aluminum oxide was used as a support material. Lanthanum oxide promoted the activity of the fresh catalysts in CO and C3H6 oxidation. Overall, Ir is a promising co-metal candidate for Pd-based catalyst for improving CO and C3H6 oxidation activity of the catalyst under stoichiometric conditions.