Catalytic hydrolysis of CCl2F2 in the presence of water vapor and air was studied over a series of metal sulfates. TiOSO4 displayed the highest activity among these sulfates, over which the conversion of CCl2F2 reached 100% at 310 degreesC. Supporting TiOSO4 on nanosized anatase TiO2 further increased its activity. CCl2F2 decomposed completely on the supported catalysts at 260-265 degreesC. The effects of TiOSO4 loading, calcination temperature, and properties of support on activity of the supported catalysts were investigated. The activity of this type of catalyst correlates well with its specific surface area and the amount of medium-strong acid sites on the surface. No deactivation of the catalyst was observed during 360 h on stream at 260 degreesC. CO was not detected in the effluent gas and the selectivity to CCIF3 in the product remained lower than 0.5%.