Preparation And Photocatalytic Activity Of Non-metallic Iodine And Ce-doped Titanium Dioxide

TiO2 photocatalytic technology has been widely applied in the treatment of refractory pollutants because of its non-toxicity, mild reaction conditions and good selectivity etc. However, the wide band gap (Eg=3.2eV), makes it absorb only UV light ofλ<387nm. And the easy recombination of photoinduced electrons and holes result in a low efficiency of photocatalysis and seriously limit the practical application of TiO2. In order to improve the photocatalytic activity, the photocatalysts such as I-TiO2,I-TiO2/Bentonite, I-Ce-TiO2 and I-Ce-TiO2/Bentonite are prepared and characterized by various techniques, such as XRD, XPS, FT-IR and UV-Vis DRS. Their photocatalytic activities of dye sulforhodamine (SRB) degradation are studied.The results show that:(1)The photocatalysts such as I-TiO2 and I-TiO2/Bentonite with different iodine content, TiO2 and TiO2/Bentonite are prepared by hydrothermal method. The catalyst Ti:I=1:1 has a low photocatalytic activity under UV and visible light. The photocatalytic activity of other catalysts is better under UV light and visible light irradiation. Under the visible light, the photocatalytic activity of I-TiO2of Ti:I=6:1 is better than other I-TiO2. And the activity of TiO2/Bentonite is better because of its good adsorption.(2)The photocatalysts such as I-Ce-TiO2 and I-Ce-TiO2/Bentonite with different iodine and cerium content are prepared by hydrothermal and sol-gel method. The results show that the optimal photocatalytic activities of I-Ce-TiO2 and I-Ce-TiO2/Bentonite prepared by hydrothermal method are Ti:I:Ce=7:1:1 and Ti:I:Ce=5:1:1 under visible light. the optimal photocatalytic activities of I-Ce-TiO2 and I-Ce-TiO2/Bentonite prepared by sol-gel method are Ti:I:Ce=100:1:1 and Ti:I:Ce=100:3:3. The photocatalytic activity of I-TiO2,Ce-TiO2 and I-Ce-TiO2 prepared by hydrothermal method is I-TiO2>I-Ce-TiO2> Ce-TiO2.(3)In order to study the effect of calcination temperature on photocatalytic activity, the photocatalysts such as I-Ce-TiO2 and I-Ce-TiO2/Bentonite (Ti:I:Ce=7:1:1) are prepared at different calcination temperature between 300℃to 700℃by hydrothermal method. The results show the photocatalytic activities of I-Ce-TiO2å'ŒI-Ce-TiO2/Bentonite decrease with the increase of calcination temperature under visible light.