Effect of Cerium Oxide and Zirconium Oxide to Activity of Catalysts

Abstract

In this work, the activities of platinum over alumina promoted with cerium oxide and zirconium oxide were investigated. Each support contained various weight percents of cerium oxide and zirconium oxide to alumina was prepared by sol gel method. The weight percent of cerium oxide to zirconium oxide was kept constant at 60 to 40. Specific surface areas of each support were measured. It was found that the addition of 20%CeO2-ZrO2 in alumina support offered the highest specific surface area of 215 m2/g. Furthermore, crystalline phase and size of mixed oxide were determined by XRD. XRD results also showed that Ce2Zr2O7 was formed in the support. The amount of cerium oxide, zirconium oxide and alumina had a strong effect to their crystalline size in the final form. Then, each support was impregnated with 1%Pt loading and tested its activity to CO oxidation reaction. The results showed that T1/2 of each catalyst was 210oC, 139oC, 145oC, 150oC and 261oC for a 1%Pt/ Al2O3, a 1%Pt/20%CeO2-ZrO2/Al2O3, a 1%Pt/40%CeO2-ZrO2/Al2O3a 1%Pt/60%CeO2-ZrO2/Al2O3 and a 1%Pt/CeO2-ZrO2, respectively. The enhancement of activity of platinum over alumina catalyst resulted from an oxygen storage property of cerium oxide together with zirconium oxide. Finally, the 1%Pt/40%CeO2-ZrO2/Al2O3 has showed the best activity to CO oxidation.