The effect of rare earth modification on ceria–zirconia solid solution and its application in Pd-only three-way catalyst

The influence of rare earth elements (La, Nd, Pr, Sm and Y) addition to Ce0.2Zr0.8O2 and its supported Pd-only three-way catalysts has been investigated by X-ray diffraction (XRD), N2 adsorption/desorption, X-ray photoelectron spectroscopy (XPS) and H2 temperature programmed reduction (H2-TPR) techniques, and that the dynamic oxygen storage capacity (DOSC) has also been evaluated under transient conditions. Special attention was given to the information of structural modification and the effect of doping on the three-way catalytic performance. The phase for all the ceria–zirconia-rare earth ternary solid solution is single tetragonal, irrespective of the treatment temperature applied. The presence of La, Nd and Pr results in enhanced thermal stability, improved reducibility and increased strong metal–support interaction, leading to the relatively higher three-way catalytic activity for all the target pollutants over the corresponding catalysts. The air/fuel operation window is also enlarged due to the increased dynamic oxygen storage capacity.

Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (81 K)Download as PowerPoint slideHighlights► The effect of rare earth doping on Ce0.2Zr0.8O2 solid solution is investigated. ► The doping effect on the supported Pd-only three-way catalyst is also studied. ► The addition of La, Nd and Pr results in improved textural/structural properties. ► The addition of La, Nd and Pr leads to improved three-way catalytic performance.