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

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The catalytic purification of soot particles is dependent on the SO 2 tolerance and activity of the catalysts in practical application. Herein, we have elaborately fabricated the nanocatalysts of three-dimensionally ordered macroporous (3DOM) Al 2 O 3 -supported binary Pt–cobalt oxide nanoparticles (NPs) using the method of gas bubbling-assisted membrane precipitation (GBMP), abbreviated as Pt–CoO x /3DOM-Al 2 O 3 . Three-dimensionally ordered macroporous Al 2 O 3 support can not only improve the contact performance between the soot and active sites but also possess surface acidity to improve the SO 2 tolerance. Supported binary Pt–CoO x NPs over 3DOM-Al 2 O 3 have high-efficient properties for activating NO and O 2 . The Pt–CoO x /3DOM-Al 2 O 3 catalyst exhibits super catalytic performance and SO 2 tolerance during the removal of soot particles, whose values of turnover frequency (TOF) and T 50 are 0.29 h –1 and 368 °C, respectively. The catalytic and SO 2 -tolerant mechanisms of the Pt–CoO x /3DOM-Al 2 O 3 catalyst for soot purification are systematically studied by in situ diffuse reflectance infrared Fourier transform (DRIFT) spectra. The synergistic effect of binary Pt–CoO x NPs plays a vital role in the oxidation of NO to NO 2 as a key step during catalytic soot removal, and the surface acidity of 3DOM-Al 2 O 3 can not only inhibit the adsorption of SO 2 but also enhance the decomposition of surface hydrosulfate species. This work provides a novel strategy to the development of high-efficient catalysts for SO 2 -tolerant catalytic removal of soot particles in both fundamental research and practical applications.