Metal-support interaction in supported Pt single-atom catalyst promotes lattice oxygen activation to achieve complete oxidation of acetone at low concentrations

Abstract

A precious metal catalyst with loaded Pt single atoms was prepared and used for the complete oxidation of C₃H₆O. Detailed results show that the T₁₀₀ of the 1.5Pt SA/γ-Al₂O₃ catalyst in the oxidation process of acetone is 250°C, the TOF of Pt is 1.09 × 10^-2 s^-1, and the catalyst exhibits good stability. Characterization reveals that the high dispersion of Pt single atoms and strong interaction with the carrier improve the redox properties of the catalyst, enhancing the adsorption and dissociation capability of gaseous oxygen. DFT calculations show that after the introduction of Pt, the oxygen vacancy formation energy on the catalyst surface is reduced to 1.2 eV, and PDOS calculations prove that electrons on Pt atoms can be quickly transferred to O atoms, increasing the number of electrons on the σ_p* bond and promoting the escape of lattice oxygen. In addition, in situ DRIFTS and adsorption experiments indicate that the C₃H₆O oxidation process follows the Mars-van Krevelen reaction mechanism, and CH₂=C(CH₃)=O_(ads), O*(O₂^-), formate, acetate, and carbonate are considered as the main intermediate species and/or transients in the reaction process. Particularly, the activation rate of O₂ and the cleavage of the -C-C- bond are the main rate-determining steps in the oxidation of C₃H₆O. This work will further enhance the study of the oxidation mechanism of oxygenated volatile organic pollutants over loaded noble metal catalysts.