Oxidation of soot promoted by Fe-based spinel catalysts

Diesel engine has attracted much attention because of its good power performance, fuel economy, reliability and durability, but the exhaust gas containing soot has a great impact on the environment and human health. Catalyzed diesel particulate filter (CDPF) that reduces the activation energy of soot oxidation and combustion by catalysts are used to eliminate soot. In this paper, MFe2O4 spinel (M=Cu, Ni and Co) was synthesized by sol-gel method to catalyze the combustion of soot. The Characterization results of MFe2O4 showed that CuFe2O4 possessed the smallest average grain size (65.6nm) and the best redox performance. The activity test of the catalyst shows that the activity order of the catalyst is CuFe2O4 (330 °C > CoFe2O4 (411 °C > NiFe2O4 (464 °C). DFT results showed that carbon is more easily adsorbed on the oxygen-terminal surface of CuFe2O4 and reacts with oxygen vacancies, resulting in the promotion of soot oxidation by the diffusion of oxygen from the inside to the surface. It also proves that CuFe2O4 has the best catalytic effect on soot.