Morphology controllable synthesis of Pd/CeO2–ZrO2 catalysts and its structure-activity relationship in three-way catalytic performance

• Published in: Progress in natural science 2021-10, Vol.31 (5), p.656-663
• Main Authors: Wan, Jie, Yang, Xue, Wang, Ting, Liu, Yanjun, Zhou, Yuanyuan, Wu, Gongde, Zhou, Renxian
• Format: Article
• Language: English
• Subjects: CeO2–ZrO2; Morphology; Palladium; Structure-activity relationship; Three-way catalysts
• ISSN: 1002-0071
• DOI: 10.1016/j.pnsc.2021.08.002

CeO2–ZrO2 mixed oxides with controlled morphologies (i.e., nanorod, nano-polyhedral and disordered shape) were synthesized through either hydrothermal or coprecipitation method, and the corresponding supported Pd/CeO2–ZrO2 catalysts were also prepared by conventional impregnation. The obtained catalysts were subjected to systematic structural/physio-chemical characterizations as well as three-way catalytic performance evaluations. The results showed that CeO2–ZrO2 mixed oxides presented different exposed crystal planes: namely disordered CZ-di mainly exposed (111) crystal planes, nanorod CZ-ro mainly exposed (111) crystal planes and few (100) crystal planes, while nano-polyhedral CZ-po exposed both (111) and (100) crystal planes. Clear structure-activity relationship could be demonstrated between the TWC (Three-way catalysts) performance of Pd/CeO2–ZrO2 and such different microstructures, as (100) and (111) crystal planes exposed by CZ-ro and CZ-po were beneficial for the surface oxygen vacancies formation, thus increasing the Pd-support interaction and effectively decreasing the light-off temperature of HC and NO elimination. On the other hand, the disordered CZ-di retained more lattice oxygen content, leading to better catalytic activity of CO elimination for the corresponding Pd/CZ-di catalyst. Pd/CeO2–ZrO2 with different morphologies presents different exposed crystal planes, and clear structure-activity relationship can be demonstrated between TWC performance and morphology control induced microstructures. [Display omitted] •Morphology controlled CeO2–ZrO2 nano-oxides were synthesized.•Different exposed crystal planes modulated via morphology control.•Structure-activity relationship induced by morphology control demonstrated.•Exposed (100) plane of CZ-po promotes surface VO formation for better HC and NO activity.•Lattice oxygen content retained on disordered CZ-di and favors CO activity.