Investigation of alkali metals addition on the catalytic activity of CuFe2O4 for soot oxidation

Soot particle exhausted from diesel engines are causing severe health and environmental problems. Alkali metals (Li, Na, K, Cs) doped CuFe2O4 catalysts were synthesized to eliminate soot residue. XRD, Raman, SEM, H-2-TPR and temperature-programmed oxidation (TPO) were employed to investigate the effect of alkali metals addition on CuFe2O4. Density functional theory (DFT) calculations were used to explore the inner reaction mechanism. The results revealed that the doping of all alkali metals facilitated the formation of oxygen vacancies which are the main active sites for soot oxidation. The CuFe2O4 doped by K showed smallest crystal size and the most oxygen vacancies. Therefore, Cu0.9K0.1Fe2O4 catalyst performed best catalytic activity in soot oxidation with the T-ig of 308 ? and T-max of 389 ?.