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 Ce0.9Zr0.1O2 (CZO) support, the Pt single atoms (Pt1) with different strength of Pt-CeO2 interaction and coordination environment were successfully constructed (Pt/CZO-X, X = the calcination temperature in oC). With the increase of calcination temperature from 350 to 750 oC, stronger Pt-CeO2 interaction and higher Pt-O-Ce coordination number were achieved due to the reaction between PtOx and surface Ce3+ species as well as the migration of Pt1 into the surface lattice of CZO (Fig. 1a-f). Pt/CZO catalyst calcined at 750 oC (Pt/CZO-750) was found to exhibit a surprisingly higher C3H8 oxidation activity than that calcined at 550 oC (Pt/CZO-550) (Fig. 1g). Pt/CZO-750 also exhibited much better H2O resistance than Pt/CZO-550 (Fig. 1h). 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, well explaining the higher C3H8 oxidation activity on Pt/CZO-750 comparing to Pt/CZO-550. This work provides a new concept for fine-tuning the surface structure of Pt1-CeO2 based catalysts, achieving high efficiency in hydrocarbons oxidation for emission control applications.

Pt single atom catalyst embedded in ceria-zirconia surface lattice with improved activity for propane oxidation

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