Oxide supported Pt-based heterogeneous catalysts accelerate many critical reactions for chemical conversion. Utilizing all individual Pt atoms as a reaction site is a promising route for sustainable use of earth unabundant and expansive Pt. However, thermodynamic vulnerability of Pt single-atoms (SAs) under the reaction conditions questions the practical value of Pt-SAs. Moreover, whether the inherent catalytic nature of Pt-SAs is superior to that of the larger Pt clusters of nanoparticles is under debate. In this study, we address above critical controversies by comparatively studying the catalytic activity and stability of Pt-SAs supported on a conventional TiO2 or a precisely designed CeOx/TiO2 hybrid-oxide support toward environmentally relevant CO oxidation reaction. By utilizing the heterogeneous interface formed between TiO2 supporting particles and CeOx clusters formed on the surface of TiO2, we preferentially synthesized Pt-SAs pinned at the CeOx-TiO2 interfaces on CeOx-TiO2 hybrid-oxide supports. The strong electronic coupling between the Pt-SAs and the Ce ions at the CeOx-TiO2 interfaces promoted the catalytic activity toward CO oxidation of Pt-SAs and improved the long-term stability under the CO oxidation conditions. The CO oxidation activity of Pt-SAs stabilized at the CeOx-TiO2 was improved by 13.5 times at 200 °C compared with the Pt-SAs on TiO2. The results present how to easily improve the activity and stability of Pt-SAs using simple interface control method. Our study delivers comprehensive understating about the catalytic nature as well as a novel strategy toward applications of Pt-SAs, enabling sustainable use of Pt in heterogeneous catalysts.

Interface-confined Pt-single atoms with high activity toward CO oxidation and excellent stability: Pt/CeOx-TiO2

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.