Catalysts of 3D ordered macroporous ZrO2-supported core–shell Pt@CeO2−x nanoparticles: effect of the optimized Pt–CeO2 interface on improving the catalytic activity and stability of soot oxidation

Abstract

We successfully synthesized 3D ordered macroporous (OM) Pt@CeO_2−x/ZrO₂ catalysts by a co-precipitation method. This series of catalysts have a well-defined 3D-OM structure. We investigated the activity of the 3D-OM Pt@CeO_2−x/ZrO₂ catalysts with different shell thicknesses, and systematically studied the adsorption and desorption of NO on the 3D-OM Pt@CeO_2−x/ZrO₂via in situ DRIFTS. The 3D-OM support enhances the contact efficiency between the solid reactant and catalyst, while the Pt@CeO_2−x core–shell nanoparticles with strong Pt–CeO_2−x interaction lead to a larger number of active species. With increasing the Ce/Pt molar ratio, the thickness of the shell becomes larger and the activity of Pt@CeO_2−x/ZrO₂ becomes lower. Among the as-prepared core–shell catalysts tested, the 3D-OM Pt_1.0@CeO_2−x/ZrO₂-1 catalyst with the proper thickness of CeO_2−x nanolayer shell showed the highest catalytic activity for soot combustion.