Frontier orbital strategy on oxygen vacancy cluster-enriched Pt/CeO2 for enhanced CO preferential oxidation

Abstract

In the field of heterogeneous catalysis, rational design and development of highly efficient catalysts based on structure–activity relationships are increasingly important. This study predicted the structural features of Pt/CeO₂ catalysts exhibiting highly efficient CO preferential oxidation (CO-PROX) activity through density functional theory (DFT) calculations and successfully synthesized them experimentally. Frontier Orbital Theory predicts that electron-deficient Pt sites form O–Pt–O interfacial bonds with CeO₂, while their partially occupied 3d_yz orbital (HOMO) hybridizes with the CO 2p_z orbital to enhance CO adsorption. Concurrently, adjacent Ovc sites promote O₂ activation through LUMO localization and orbital hybridization with Ce, significantly lowering the O–O dissociation energy barrier. Using a novel scalable precursor combustion method, we successfully synthesized atomically dispersed Pt/CeO₂ catalysts with the aforementioned structural features. The optimized Pt/CeO₂-800 achieved near-complete CO conversion (96%) at the proton exchange membrane fuel cell (PEMFC) operating temperature (70 °C) and maintained 80 hour stability under industrially-relevant gas space-velocity conditions. In-situ DRIFTS and DFT calculations confirmed that the synergy between electron-deficient Pt sites and oxygen vacancy clusters drives the atomically dispersed Pt/CeO₂ catalyst to achieve highly efficient CO preferential oxidation. This work provides powerful guidance for the rational design approach combining theory and experiment for CO-PROX catalysts.