磷钨酸掺杂二氧化钛光催化剂的吸附性能及光催化活性

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.%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.