Evolution of Pd chemical states and effects of C3H6 and H2O on the CO oxidation over Pd/CeO2 catalyst

• Published in: Applied surface science 2022-10, Vol.599, p.153897, Article 153897
• Main Authors: Wang, Mingzhi, Ma, Peijie, Wu, Zhuangzhuang, Chu, Shasha, Zheng, Yanping, Zhou, Zhaohui, Weng, Weizheng
• Format: Article
• Language: English
• Subjects: Ce1−xPdxO2−δ; CO oxidation; Pd-CeO2 interface; PdO; Redox property
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2022.153897

[Display omitted] •Pd/CeO2 catalysts dominated with either PdO or Ce1−xPdxO2−δ species were prepared.•Evolution of Pd species under CO and CO + C3H6 oxidation conditions was investigated.•Chemical states of the two Pd species under CO oxidation condition are different.•Redox properties of Pd species play a key role in determining its catalytic behavior.•Inhibition effect of C3H6 on CO oxidation can be alleviated by adding H2O. Determination of dynamic changes of the supported Pd catalysts under the reaction conditions of CO/Hydrocarbons (HCs) oxidation is of great importance to the development of high performance catalysts for vehicle exhaust purification. Here we found that Pd/CeO2 catalysts dominated with either PdO or Ce1−xPdxO2−δ species, obtained by modulating the interaction between the Pd precursors and the CeO2 support during the preparation, show different dynamic properties under the conditions of CO oxidation and also different deactivation behaviors when C3H6 is coexisting. Under the CO oxidation condition, the PdO species can be easily reduced to metallic Pd, whereas the Ce1−xPdxO2−δ species remain mainly as ionic Pd2+. In situ IR characterization revealed that the chemical states of Pd species on CeO2 during CO oxidation were related to their redox properties, which also dramatically affect the role of C3H6 and H2O in the reactions.