Ceria supported platinum catalyst for CO oxidation reaction: Importance of metallic active species - Commemorating the 100th anniversary of the birth of Academician Guangxian Xu

Ceria supported platinum catalyst has now been widely studied due to its excellent activity for CO oxidation. However, the electron state of active metal center is still an open question. In this work, a ceria nanorod support was prepared and platinum (Pt) with 0.9 ate was deposited using an impregnation method to obtain Pt/CeO2 catalyst. With the help of light-off experiment and temperature programmed reduction under CO (CO-TPR) test, the conclusion is proposed that the process of hydrogen reduction can enhance the activity of CO oxidation reaction for the generation of optimal active Pt site. An innovative near-situ X-ray absorption fine structure (XAFS) technique was used to investigate the chemical state of central Pt atom during the reaction process, clearly demonstrating that the high oxidized state of Pt does harm to the activity for CO oxidation while the relatively reductive Pt exhibits high activity, and the different oxidized state and chemical environment of Pt during every process has been identified. Furthermore, the activity of our Pt/CeO2 catalyst is superior to that of most of the previous reports about CO catalytic oxidation by Pt based catalyst. Moreover, the optimal active species (Pt-O-4) have been identified after hydrogen reduction, which could be a possible key strategy to control the oxidation of Pt. (C) 2021 Published by Elsevier B.V. on behalf of Chinese Society of Rare Earths.

Automated summary

Pt/CeO2 catalyst prepared in this study showed enhanced activity for CO oxidation after hydrogen reduction. Different oxidation states of Pt were found to affect the catalytic activity, with Pt-O-4 identified as the optimal active species.