Effect of Rare Earth Metal (RE = La, Pr, Nd, Y) Doping on Co–Ce Composite Oxide and Its Application in Catalytic Combustion of Chlorobenzene

Rare earth metal (RE = La, Pr, Nd, Y)-doped CoCeO x catalysts were prepared and evaluated for eliminating chlorobenzene (CB). Characterization results showed that the doped RE metal simultaneously acts as a structural and electronic assistant, which changes the coordination environment of Ce ions and enhances the interaction between Co and Ce species, thus improving the catalytic performance and chlorine resistance of CoCeO x . Besides, dynamic “redox gears” based on the Co/Ce redox couples were proposed. RE metal doping was found to promote the movement of “gears”, which led to increased surface active oxygen and oxygen mobility, accelerating the complete oxidation of CB and the rapid removal of deposited chlorine. CoCeYO x exhibited the best redox-promoting effect, with 90% CB conversion observed at 256 °C and reduced generation of dichlorobenzene. Moreover, the effect of gaseous oxygen on the CB oxidation process was also studied.