Effect of iron doping into CeO2-ZrO2 on the properties and catalytic behaviour of Pd-only three-way catalyst for automotive emission control.

Ce(0.67)Zr(0.33)O(2) doped with iron oxide was prepared and the corresponding Pd-only three-way catalysts were examined and characterized. Pd/CZFe(1%) catalyst exhibits the best catalytic performance for CO, HC, NO and NO(2) elimination and the widest operation window. The doping of iron oxide with 1% loading suggests the formation of more homogeneous Ce-Zr-Fe-O ternary solid solution, which seems to facilitate the reduction of Ce(4+)→Ce(3+) or the formation of oxygen vacancy and to promote the interaction between Ce-Zr and Fe. Moreover, the Ce redox behaviour for surface reduction suggests depending not only on the formation of homogeneous Ce-Zr-Fe-O but also on the surface property of the sample. The increase in the concentration of oxygen vacancies under all atmospheres for CZFe(1%) sample also results in the enhancement of oxygen storage complete capacity.