Enhanced Soot Oxidation Activity of a CuO-Doped CeO₂ Catalyst via Acid Etching

Copper oxides tend to agglomerate on the surface of CeO2, with a high amount of Cu. In this study, a CeO2 catalyst with a high CuO doping amount was treated with nitric acid to improve its catalytic performance for soot oxidation. The effect of acid etching on the structural properties of the CuO-doped CeO2 catalyst were elucidated. The characterization results indicated that aggregated CuO particles formed over CuCe. The acid etching resulted in a remarkable increase in the surface area of CuCe. Additionally, acid etching promoted the formation of surface-adsorbed oxygen species and oxygen vacancy, and reduced the content of CuOx species with weak interaction with CeO2. The soot temperature-programmed oxidation results show the acid etching of CuCe catalyst could reduce the T-50 from 443 to 383 degrees C. The isothermal reaction results also suggest that acid etching of CuCe leads to an increase in reaction rate from 16.2 to 46.0 mu mol min(-1) g(-1).