Structure characterization and catalytic performance of high surface area Ce_xTi_1-xO₂ catalysts in HCl oxidation

A series of Ce_xTi_1-xO₂ catalysts were prepared by ammonia co-precipitation method. The physiochemical properties of the catalysts were characterized by XRD, Raman, N₂ adsorption-desorption and H₂-TPR. The cataly- tic performances of the samples for the gas-phase HCl oxidation to recycle Cl₂ were investigated. The results of XRD and Raman showed that mixed oxides were more dispersed than pure CeO₂ and TiO₂, even existed as the amorphous structures, leading to the special surface areas of mixed oxides much higher than that of pure CeO₂ and TiO₂. Ce_0.1Ti_0.9O₂ possessed a surface area as high as 170.5 m²·g^-1. Meanwhile, the results of H₂-TPR showed that the reducibility of the mixed oxides was greatly improved by the interaction of CeO₂ and TiO₂. Mixed oxides showed higher activities than pure CeO₂ and TiO₂. The STY (space time yield) of Cl₂ over Ce_0.1Ti_0.9O₂ reached to 0.90 g_Cl2·g_cat^-1·h^-1 at 430 ℃. The long-term stability test showed Ce_0.1Ti_0.9O₂ can maintain its activity at 0.76 g_Cl2·g_cat^-1·h^-1 after 60 h on stream.