Abstract: A series of Cu-Mn catalyst samples with Ce additive supported on palygorskite (PG) were prepared by the wet impregnation method. The catalyst structure was characterized by X-ray diffraction, transmission electron microscopy (TEM), and temperature-pro- grammed reduction with H₂. The state of various active species and their reducibility were investigated and correlated with catalytic performance of the catalyst. The catalyst activity was examined using toluene as a model volatile organic compound. The effect of different active species, the amount of Ce additive, and catalyst calcination temperature on toluene conversion was investigated. The results demonstrated that the active species of the catalyst were loaded on the surface of PG in the form of CuO, Mn₂O₃, and CeO₂, and highly dispersed nanoparticles of the species were observed by TEM. The addition of Ce improved the growth of spinal CuMn₂O₄ and increased toluene conversion. When molar ratio of Ce/Cu was 0.3, the catalyst showed the highest activity. Toluene conversion reached 99% over the Cu-Mn-Ce/PG catalyst at 288 ^oC.

Key words: palygorskite, copper, manganese, cerium, catalytic oxidation, volatile organic compound, toluene