Abstract:

A series of titanium dioxide (TiO₂) photocatalysts doped with H₃PW₁₂O₄₀ were synthesized by sol-gel method using tetrabutyltitanate [Ti(OC₄H₉)₄] and H₃PW₁₂O₄₀ as precursors. The as-prepared photocatalyst was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV-vis adsorption spectroscopy. The adsorption performances and photocatalytic activities of the prepared samples were estimated by measuring the adsorption and degradation rate of methyl blue (MB) in an aqueous solution. The results of MB adsorption showed that H₃PW₁₂O₄₀-doped TiO₂ exhibited higher adsorption performance than pure TiO₂ and the adsorption isotherm of MB on photocatalyst could be described better by Langmuir equation than Freundlich equation. The effects of catalyst dosage and H₃PW₁₂O₄₀-doped content on the photocatalytic degradation of MB were studied. It was shown that the H₃PW₁₂O₄₀-doped TiO₂ had a stronger absorption and could thus be used as an effective catalyst in photo-oxidation reactions. In addition, the possibility of cyclic usage of H₃PW₁₂O₄₀-doped TiO₂ was also confirmed. The photocatalytic activity of the photocatalyst remained was above 88% of that of the fresh sample after being used four times.

Key words: H₃PW₁₂O₄₀, titanium dioxide, methyl blue, adsorption, catalysis, photocatalytic activity, experimental validation

摘要：

以钛酸四丁酯和无水乙醇为原料,采用溶胶-凝胶法制备了磷钨酸掺杂二氧化钛(H₃PW₁₂O₄₀-TiO₂)光催化剂,并利用XRD、SEM、DRS等对掺杂前后二氧化钛的结构进行了表征。在光催化实验初期的暗反应之后,发现H₃PW₁₂O₄₀-TiO₂光催化剂的吸附效果很好。对H₃PW₁₂O₄₀-TiO₂光催化剂的吸附性能进行了研究,结果表明,相比于Freundlich方程,Langmuir方程能更好地描述其吸附平衡。H₃PW₁₂O₄₀-TiO₂光催化剂与纯TiO₂相比有更好的吸附性能,吸附时间为70 min的条件下H₃PW₁₂O₄₀-TiO₂对亚甲基蓝(MB)的脱色率可达90%以上。通过自行设计的光催化反应器考察了光催化剂用量、磷钨酸掺杂量等因素对光催化降解MB性能的影响。结果表明:H₃PW₁₂O₄₀-TiO₂在紫外和可见光区域有较强的吸收,对MB溶液具有更好的光催化降解效果,而且该复合材料有较高的循环回收利用率。

关键词: 磷钨酸, 二氧化钛, 亚甲基蓝, 吸附, 催化, 光催化活性, 实验验证