We are involved in complete removal of VOC (volatile organic compounds) by the use of thermally generated holes in oxide semiconductors. In the present investigation, we have studied VOC decomposition characteristics of Cr₂O_3+x (0<x<1) in a fluidized bed system, as well as in a honeycomb-like cartridge system which includes 15 mesh disks coated with Cr₂O₃ powders. In both systems, Cr₂O_3+x is found to exhibit an excellent decomposition characteristic which even exceeds that of the TiO₂ system, although the specific surface of Cr₂O_3+x (3m²/g) is only 1/100 of powdered TiO₂ (298m²/g).