Enhancing the Carbon Monoxide Oxidation Performance through Surface Defect Enrichment of Ceria-Based Supports for Platinum Catalyst.

Abstract

Effective synthesis and application of single-atom catalysts on supports lacking enough defects remain a significant challenge in environmental catalysis. Herein, we present a universal defect-enrichment strategy to increase the surface defects of CeO₂-based supports through H₂ reduction pretreatment. The Pt catalysts supported by defective CeO₂-based supports, including CeO₂, CeZrO_x, and CeO₂/Al₂O₃ (CA), exhibit much higher Pt dispersion and CO oxidation activity upon reduction activation compared to their counterpart catalysts without defect enrichment. Specifically, Pt is present as embedded single atoms on the CA support with enriched surface defects (CA-HD) based on which the highly active catalyst showing embedded Pt clusters (Pt_C) with the bottom layer of Pt atoms substituting the Ce cations in the CeO₂ surface lattice can be obtained through reduction activation. Embedded Pt_C can better facilitate CO adsorption and promote O₂ activation at Pt_C-CeO₂ interfaces, thereby contributing to the superior low-temperature CO oxidation activity of the Pt/CA-HD catalyst after activation.