Preparation of Ce0.5Zr0.5O2–Al2O3 with high-temperature sintering resistance and its supported Pd-only three-way catalyst

Abstract

In this study, three Ce0.5Zr0.5O2–Al2O3 composites were synthesized using co-precipitation method with different precursor mixing ways. Differences in structural, textural, reduction properties and catalytic performance, in combination with the aging behaviors of the supports and catalysts, were systematically explored. For CZA4, Al(NO3)3·9H2O was mixed with Ce(NO3)3·6H2O and ZrOCO3 separately before being precipitated; it could inhibit the phase separation and crystalline growth as well as exhibit resistance against sintering. Besides, CZA4 exhibited the higher surface Ce3+ species and Ce surface content, which was more beneficial to improve the redox performance. In addition, the as-prepared Pd/CZA4 and Pd/CZA4a also presented superior redox performance and Pd dispersion. What is more, the increase of Pd–Ce interface may be caused by the high Ce content on the surface, consequently, enhancing reduction in Pd–Ce interaction and dispersion of precious metal. Due to a series of properties after aging for CZA4a, thus the Pd–CZA4a revealed good TWCs performance.