Oxygen mobility and microstructure properties-redox performance relationship of Rh/(Ce,Zr,La)O catalysts.

Rh/(Ce,Zr,La)O (CZL) catalysts with different Ce/Zr molar ratios of 1:0, 8:1, 4:1, 2:1, 1:1, 1:2, 1:4, 1:8 and 0:1 were prepared. The relationship of microstructure, dynamic oxygen mobility and the redox properties with catalytic activity for HC, CO and NO eliminations were investigated. The results demonstrate that CZL mixed oxide with Ce/Zr ratio of 1:1 exhibits the largest OSC values as 904.3 umol·g and structural defects. The increase of oxygen vacancies and structural defects would promote the interaction between Rh species and CZL mixed oxides, which further promotes the stabilization of RhO particles and enhances the oxygen storage/release ability. Rh/CZLx catalysts with Ce/Zr molar ratio of 1:1-1:4 exhibit better catalytic activity and wider dynamic operation window due to their higher DOSC.