多孔纳晶TiO_2薄膜光催化剂的研制及其催化性能

Preparation of Nano-crystal TiO_2 Porous Thin Films and Their Photocatalytic Performance

采用sol gel法制备了纳米TiO2 溶胶 ,并在制备过程中加入丙烯酸对生成的纳米TiO2 胶体颗粒进行表面修饰 ,该有机包裹膜可有效抑制颗粒在反应、老化及热处理过程中发生团聚 .老化 2 4h后的溶胶加入聚乙二醇作为扩孔剂 ,以载玻片为底材 ,用涂敷法将溶胶负载于玻片表面上 ,经高温焙烧得到与底材结合紧密 ,且具有多孔结构的TiO2 薄膜催化剂 .XRD结果表明 ,薄膜催化剂的晶形为锐钛矿 .对纳晶TiO2 薄膜和粉体TiO2 催化剂光催化降解活性艳红X 3B的性能进行了比较 .在催化剂用量相同的情况下 ,TiO2 粉体催化剂的活性要高于TiO2 薄膜催化剂 ,但TiO2 薄膜催化剂对活性艳红X 3B同样显示出较高的光催化氧化活性 .

Nano-crystal TiO 2 sol was prepared by sol-gel technique with tetrabutyl titanate as precursor. The aggregation of nano-TiO 2 particles can be effectively suppressed by adding acrylic acid as surface modifier in the solution. Polyethylene glycol (PEG) with different relative molecular mass ( 1*!540, 6*!000, 10*!000, 20*!000) was used in preparation of nano-TiO 2 thin films,and the nano-TiO 2 thin films with micro-pore structure were obtained by adding PEG as dispersing agent. Furthermore, the porosity increases with the increase of relative molecular mass of PEG. The analysis of DTA-TG indicated that the volatilizing temperature of water and solvent in the samples is about 57 ℃, and that the decomposition and combustion temperatures of the organics in the sample are 213 ℃ and 220～350 ℃ respectively. XRD patterns of the samples annealed at different temperatures demonstrated that the phase transform temperature is ca 700 ℃ and the aggregation of nano-TiO 2 is obviously appeared at this temperature. The proper thermotreatment temperature for nano-TiO 2 as prepared is ca 600 ℃. The photocatalytic activity of nano-TiO 2 porous thin films and TiO 2 powder catalyst for degradation of X-3B was investigated. The experimental results indicated that the two kinds of photocatalysts, especially powder photocatalyst, have high photocatalytic activity in photocatalytic degradation of X-3B. Moreover, the photocatalytic activity of nano-TiO 2 thin films with PEG is higher than that of the film without PEG.