The evolution of Pt with different initial sizes during propane oxidation over Pt–CeO2 catalysts†

Abstract

Pt-based catalysts are widely used in catalytic combustion of hydrocarbons and play an important role in emission control. However, developing a Pt catalyst for efficient conversion of hydrocarbons at low temperatures remains challenging. Herein, the structure–performance relationship between Pt size and C₃H₈ oxidation activity was studied over Pt–CeO₂ catalysts. The samples with different Pt initial states of single atoms and nanoparticles were obtained by different reduction treatments. No obvious differences were found between the two catalysts in the performances of C₃H₈ oxidation. The Pt states were found to be dynamically changing during C₃H₈ oxidation, and the evolution behaviors were closely related to the Pt initial states; Pt single atoms continuously sintered into clusters and then transformed into Pt nanoparticles with elevated reaction temperatures, while initial Pt nanoparticles firstly dispersed into small clusters and then re-sintered into nanoparticles. It is concluded that the different adsorption properties of C₃H₈ and O₂ on Pt species with different sizes are responsible for their different evolution behaviors during C₃H₈ oxidation based on DFT analyses.