Preparation And Photocatalyst Activity Of TiO₂ Composite Catalyst

As the wide application of indoor decoration materials and chemical commodities ,the problem of indoor air pollution has become more and more serious.benzene is a commonly detected volatile organic compounds (VOCs) in the door. In view of that the photocatalytic degradation efficiencies of benzene only by TiO₂ is low,this paper prepared TiC>2 supported on sorbents. the supported catalysts on sorbents have better adsorptivity, so the activity in gas-phase photocatalytic reaction of benzene is higher than that of unsupported TiO₂.The main conclusions are as below:(1) The TiO₂ -loaded adsorbents such as activated carbon, zeolite, bentonite ,diatomite were prepared .and the photocatalytic degradation of benzene in gas phase was studied.then the efficiency of photocatalytic was compared with that of naked TiO₂. The experiment results indicated that the suitable adsorbent supports make a high concentration environment of organic substances of target around the loaded TiO₂ by adsorption , and then the rate of photooxidation is enhanced. It could be inferred from the comparison that TiO₂/actived carbon have the most powerful purification ability,in turn is TiO₂/ zeolite, TiO₂/ bentonite and TiO₂/ diatomite.(2) Though the TiO₂/actived carbon have the most powerful purification ability,the adsorbents have so high adsorbabilities that the diffusion of adsorbed substances were hindered.and it also affected the adsorption of intermediate reaction product? The catalytic efficiency decreased quickly after used over several times. So this paper selected zeolite as supports which have moderate adsorblity.It was showed that when the TiO₂ content was 50%, the pH was kept around 3.0 , TiO₂ behaved a much higher activity after being sinterd at 200°C for 2 hours.And the catalytic activity is comparative steady.A processing rate of 81% still could beobtained.(3) The rate of photocatalytic degradation of benzene can be expressed in first-order kinetics model. By the TiCVzeolite The apparent rate constant of reaction is almost three times than that by naked TiC>2. It showed that the adsorbent play a important role in the inhancement of the catalytic efficiency.