Washcoating of cordierite honeycomb with ceria-copper mixed oxides for catalytic diesel soot combustion

• Ceria-based nanomaterials for soot combustion.
• A simple sol–gel method was adopted to prepare the Ce0.6Cu0.4O2 mixed oxides.
• Ce4+/Ce3+ redox couple formed facilitates oxygen transport.
• Ce0.6Cu0.4O2 has higher oxygen storage capacity.
• Cordierite supports modified with Ce0.6Cu0.4O2 can reduce soot emission during diesel burning in a stationary diesel motor.

Cordierite honeycomb monoliths coated with ceria-copper catalyst were synthesized, characterized, and used in catalytic soot oxidation. First, Ce0.6Cu0.4O2 was obtained by the sol–gel method and deposited on cordierite. The resulting material was employed to capture and oxidize soot. The coating process generated highly dispersed active species and enriched the coating surface with ceria and copper. XRD, H2-TPR, OSC, Raman spectroscopy, and SEM and TEM microscopies helped to confirm the structural and morphological properties of the material and formation of the mixed oxides. Compared with the uncatalyzed reaction, thermogravimetry analysis (TGA/DTA) of the soot oxidation in the presence of the catalysts showed that the soot oxidation temperature decreased. Raman spectroscopy studies revealed an increased number of oxygen vacancies in the Ce0.6Cu0.4O2 deposited on cordierite as compared with pure CeO2 deposited on cordierite. The coated monolithic catalyst exhibited desirable catalytic performance the soot removal rate exceeded 73% according to dynamic tests conducted in a stationary engine.