Pt-embedded-CeO2 hollow spheres for enhancing CO oxidation performance

Abstract

Exploring high-performance catalysts has always been a general concern for promoting extended heterocatalysis reactions. Here, Pt embedded highly-porous CeO₂ hollow sphere (Pt/CeO₂ HS) composites are developed by a one-pot template-free solvothermal method. Evolution mechanism studies unravel that the Pt/CeO₂ HS composites are derived from a self-assembly–reduction–Ostwald ripening process, where Pt nanoparticles (Pt NPs) are embedded into ceria mesoporous hollow spheres. The as-developed embedment strategy is more facile, sustainable and cost-effective than conventional deposition approaches, ensuring the precise control of the location, distribution, and uniformity of Pt NPs throughout the outer shell of hollow spherical CeO₂. Importantly, the Pt NP embedding process could be determined to play a key role in creating oxygen vacancies and activating surface chemisorbed oxygen. Besides that, the aggregation of Pt NPs can be efficiently inhibited in the Pt/CeO₂ HS composites, and more active sites should be involved in catalytic reactions. All these advantages contribute to the strikingly improved performance as well as excellent stability of the Pt/CeO₂ HS composites toward CO oxidation reaction compared with mesoporous CeO₂ nanospheres (CeO₂ NS) and Pt/CeO₂ NS reference catalysts. These findings present a decent protocol for desgining noble metal/oxide hollow structural composites in heterogeneous catalysis.