Investigation on properties of a novel ceria–zirconia–praseodymia solid solution and its application in Pd-only three-way catalyst for gasoline engine emission control

Different contents of praseodymia were introduced to modify Ce0.2Zr0.8O2 (CZ) and the supported Pd-only three-way catalysts before and after aging were also prepared. The influence of praseodymia doping on the structural/textural properties of CZ and the effect on the three-way catalytic activity were investigated. Structural and textural characterizations reveal that the addition of praseodymia results in the formation of Ce–Zr–Pr ternary solid solution (CZP) with higher specific surface area, better thermal stability and larger oxygen storage capacity (OSC) than that of CZ. It is more credible that Zr is replaced by Pr during the formation of CZP. The modified Pd-only three-way catalysts present relatively higher catalytic activity to the main target pollutants in gasoline engine exhaust and exhibit wider air/fuel operation window due to the improved properties of CZP.

This figure displays the CO2 response peaks over Pd/CZ, Pd/CZP5, Pd/CZa and Pd/CZP5a derived from the dynamic oxygen storage capacity (DOSC) testing. The results show that the addition of Pr into Ce0.2Zr0.8O2 (CZ) leads to enhanced DOSC of its supported Pd-only three-way catalyst no matter before and after aging.Figure optionsDownload as PowerPoint slideHighlights
► The effect of Pr doping on Ce0.2Zr0.8O2 solid solution is investigated.
► The doping effect on the supported Pd-only three-way catalyst is also studied.
► The Pr doping results in enhanced oxygen storage capacity and thermal stability.
► The Pr doping results in improved three-way catalytic activity.
► The Pr doping leads to relatively wide air/fuel operation window.