Metal-organic framework-derived CeO2 nanosheets confining ultrasmall Pd nanoclusters catalysts with high catalytic activity. (18th November 2021)

• Record Type: Journal Article
• Authors: Ye, Jingrui; Cheng, Dang-guo; Chen, Fengqiu; Zhan, Xiaoli
• Is Part Of: International journal of hydrogen energy. Volume 46:Number 80(2021)
• Page Start: 39892
• Page End: 39902
• Publication Date: 2021-11-18
• Subjects: Confinement -- MOF derivates -- Pd/CeO2 catalysts -- Pd clusters; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2021.09.254
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: An in-situ assembly method was successfully constructed to encapsulate Pd clusters within CeMOF matrix. This method involved the protection of nanoclusters with PVP and the assembly of CeMOF around Pd nanoclusters under mild condition. The small size and high dispersion resulting from physical confinement effect were inherited in the derivates as CeO2 nanosheets confining Pd nanoclusters catalysts. The relative position of Pd and Ce was regulated via varying pyrolysis parameter, which determined the confinement state of Pd clusters. A critical state was found where Pd clusters were maintained at high dispersion and possessed unlimited accessibility for CO. The specific confining structure and low surface concentration depressed the oxygen supply, resulting in the formation of substoichiometric PdOx, which interacted with CeO2 and formed Pd–Ce–O(s) clusters. With the improved dispersion and high content of Pd–Ce–O(s) clusters, the catalyst converted 100% CO at 63 °C with a Pd loading of 1.07%. The reaction followed Mars-van Krevelen mechanism, in which CO adsorbed on Pd–Ce–O(s) clusters and reacted with the highly active oxygen species. Highlights: Pd clusters were successfully confined within Ce-based MOF matrix. The MOF-derived Pd–CeO2 exhibits high catalytic performance for CO oxidation. The formation and reaction mechanism of Pd–Ce–O(s) clusters were investigated.