Optimized Pt-MnOx interface in Pt-MnOx/3DOM-Al2O3 catalysts for enhancing catalytic soot combustion

The catalysts of three-dimensionally ordered macroporous (3DOM) Al₂O₃-supported core-shell structured Pt@MnO_x nanoparticles (3DOM-Pt@MnO_x/Al₂O₃) were successfully prepared by the gas bubbling-assisted membrane reduction-precipitation (GBMR/P) method. Pt@MnO_x core-shell nanoparticles (NPs) are highly dispersed on the inner surface of 3DOM-Al₂O₃ support. Pt@MnO_x/3DOM-Al₂O₃ catalysts, which combine both advantages of high-efficiency soot-catalyst contact by 3DOM-Al₂O₃ structure and the abundant active sites by the optimized Pt-MnO_x interface, exhibit high catalytic activities for soot combustion, and the catalytic activities are strongly dependent on the thickness of MnO_x shell. Among the catalysts, 3DOM-Pt@MnO_x/Al₂O₃-1 catalyst with optimized Pt-MnO_x interface shows the highest catalytic activity for soot combustion, i.e., its values of T₅₀ and S_CO2^m are 351 °C and 98.6%, respectively. The highest density of Pt-MnO_x active sites for adsorption-activation of gaseous O₂ is responsible for enhancing catalytic activity for soot combustion. Pt@MnO_x/3DOM-Al₂O₃ catalysts are promising to practical applications for the emission reduction of soot particles.