Effect of Cs promoter on the activity of Pd/ZnO catalyst for selective oxidation of CO in H2-rich gas

The selective oxidation of CO in H2-rich gas has been investigated with various supported Pd catalysts and alkali metal modified Pd/ZnO catalysts. The supported Pd catalysts, such as Pd/Ga2O3, Pd/SiO2, Pd/CeO2, Pd/In2O3, Pd/Al2O3 and Pd/ZnO, exhibit poor activity and selectivity for the oxidation of CO, with which oxidation of H2 occurs predominantly. However, upon the addition of alkali metals such as Cs and Rb, the catalytic performance of Pd/ZnO catalyst is significantly improved.