Control of diesel particulate emission based on Ag/CeOx/FeOy catalysts supported on cordierite

• Ceria-based nanomaterials for soot combustion.
• Ce4+/Ce3+ redox couple formed facilitates oxygen transport.
• CeOx/FeOy mixed oxides-supported Ag catalysts are excellent system for diesel soot combustion.
• The strong Ag–CeOx/FeOy interaction can improve the redox property of them.
• Active oxygen species present in the catalyst can migrate through the metal–oxide interface.

In this study, we propose that ceria-based catalysts are capable to diminish the temperature at which the soot combustion occurs to values within the operation range of diesel engines exhaust gases. We investigated how the addition of 5 wt.% silver nanoparticles (Ag NPs) loading the CeOx/FeOy (1.5 ⩽ x ⩽ 2 and 1 ⩽ y ⩽ 1.5) catalyst affects the combustion temperature of the soot. The sol–gel methodology was used to synthesize catalysts based on ceria–iron oxide (CeOx/FeOy) modified with Ag NPs, which were obtained by reverse microemulsion synthesis, and then deposited on cordierite support. Morphological and structural properties of the nanostructured Ag-modified CeOx/FeOy catalysts were evaluated by BET, XRD, OSC, SEM, TEM, and Raman spectroscopy. Catalytic tests show that addition of Ag NPs to the CeOx/FeOy catalysts leads to a significant reduction of about 300 °C in the soot oxidation temperature. This is due to the synergistic effect between the oxide and metal phases, which leads to a higher surface oxygen mobility. As a result, we obtained catalysts with improved redox ability that exhibit high performances in diesel soot oxidation at lower temperatures, which is a highly interesting prospect for the improvement of currently used particulate filters.

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