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.