Surface Lattice-Embedded Pt Single-Atom Catalyst on Ceria-Zirconia with Superior Catalytic Performance for Propane Oxidation

Abstract

Tuning the metal-support interaction and coordination environment of single-atom catalysts can help achieve satisfactory catalytic performance for targeted reactions. Herein, via the facile control of calcination temperatures for Pt catalysts on pre-stabilized Ce_0.9Zr_0.1O₂ (CZO) support, Pt single atoms (Pt₁) with different strengths of Pt-CeO₂ interaction and coordination environment were successfully constructed. With the increase in calcination temperature from 350 to 750 °C, a stronger Pt-CeO₂ interaction and higher Pt-O-Ce coordination number were achieved due to the reaction between PtO_<i>x</i> and surface Ce³⁺ species as well as the migration of Pt₁ into the surface lattice of CZO. The Pt/CZO catalyst calcined at 750 °C (Pt/CZO-750) exhibited a surprisingly higher C₃H₈ oxidation activity than that calcined at 550 °C (Pt/CZO-550). Through systematic characterizations and reaction mechanism study, it was revealed that the higher concentration of surface Ce³⁺ species/oxygen vacancies and the stronger Pt-CeO₂ interaction on Pt/CZO-750 could better facilitate the activation of oxygen to oxidize C₃H₈ into reactive carbonate/carboxyl species and further promote the transformation of these intermediates into gaseous CO₂. The Pt/CZO-750 catalyst can be a potential candidate for the catalytic removal of hydrocarbons from vehicle exhaust.