SO2-Tolerant Catalytic Removal of Soot Particles over 3D Ordered Macroporous Al2O3-Supported Binary Pt-Co Oxide Catalysts.

The catalytic purification of soot particles is dependent on the SO2 tolerance and activity of the catalysts in practical application. Herein, we have elaborately fabricated the nanocatalysts of three-dimensionally ordered macroporous (3DOM) Al2O3-supported binary Pt-cobalt oxide nanoparticles (NPs) using the method of gas bubbling-assisted membrane precipitation (GBMP), abbreviated as Pt-CoOx/3DOM-Al2O3. Three-dimensionally ordered macroporous Al2O3 support can not only improve the contact performance between the soot and active sites but also possess surface acidity to improve the SO2 tolerance. Supported binary Pt-CoOx NPs over 3DOM-Al2O3 have high-efficient properties for activating NO and O2. The Pt-CoOx/3DOM-Al2O3 catalyst exhibits super catalytic performance and SO2 tolerance during the removal of soot particles, whose values of turnover frequency (TOF) and T50 are 0.29 h-1 and 368 °C, respectively. The catalytic and SO2-tolerant mechanisms of the Pt-CoOx/3DOM-Al2O3 catalyst for soot purification are systematically studied by in situ diffuse reflectance infrared Fourier transform (DRIFT) spectra. The synergistic effect of binary Pt-CoOx NPs plays a vital role in the oxidation of NO to NO2 as a key step during catalytic soot removal, and the surface acidity of 3DOM-Al2O3 can not only inhibit the adsorption of SO2 but also enhance the decomposition of surface hydrosulfate species. This work provides a novel strategy to the development of high-efficient catalysts for SO2-tolerant catalytic removal of soot particles in both fundamental research and practical applications.