Influence of Ceria-Zirconia Solid Solution on Performance of Noble Metal Monolithic Oxidation Catalyst

CeXZr1-XO2 solid solution was prepared by co-precipitation method,while powder and monolith honeycomb catalysts were prepared by impregnating carriers with certain CeXZr1-XO2 aqueous solution.The crystalline structures of CeXZr1-XO2 and Ce0.5Zr0.5O2/Al2O3 were characterized by XRD,and the adsorbability was examined by TPD-C3H6.The results showed that the solid solution was obtained in CeO2-ZrO2 composite oxides,the addition of CeO2-ZrO2 to γ-Al2O3 improved the adsorptive power of CeXZr1-XO2/Al2O3 to C3H6.The behavior of these catalysts was examined by propene oxidation in a fixed-bed microreactor under excess oxygen.It was found that when the adding amount of CeXZr1-XO2 was equal,Pt/Ce0.6Zr0.4O2/Al2O3/cordierite showed the best activity,which was still lower than that of Pt/Al2O3/cordierite.So the addition of ceria-zirconia solid solution restrained the catalytic activity in the presence of excessive oxygen,when the amount of noble metal such as platinum was quite low.The more the ceria-zirconia solid solution was loaded,the worse was the performance of the catalysts as oxidative catalyst.