TiO_2包覆上转换发光材料Pr^(3+)∶Y_2SiO_5的制备及其可见光催化性能的研究

Preparation of Pr^(3+)∶Y_2SiO_5/TiO_2 nanocomposites and its application in photocatalytic degradation of dyes under visible light irradiation

为了提高TiO2对可见光的利用率,通过溶胶-凝胶法制备了TiO2包覆上转换发光材料Pr3+∶Y2SiO5的复合材料,并借助XRD、TEM、紫外-可见吸收光谱等对制备的样品进行了表征和研究。同时,研究了不同条件下制备的复合粉体对罗丹明B光降解效率。结果表明,该方法制备出的Pr3+∶Y2SiO5/TiO2复合材料较纯TiO2和简单机械混合两种粉体在可见光下具有较强的光催化效果。验证了Pr3+∶Y2SiO5作为上转换发光材料,可吸收可见光发射紫外线,从而满足TiO2光催化降解的要求。文中最后对Pr3+∶Y2SiO5/TiO2复合材料的光催化机理进行了研究。

In order to enlarge the utilization ratio of the visible light, the Pr^3＋ ： Y2SiO5/TiO2 composite was prepared by sol-gel method. The as-synthesized samples were characterized by X-ray diffraction, transmission electron microscopy, and ultraviolet-visible absorption spectra. Meanwhile,the composite powder （prepared under different conditions） degradation of RhB was studied. All the results proved that the Pr^3＋： Y2SiO5/TiO2 had more excellent photocatalytic activities than pure TiO2, mixed powders （the mixture of Pr^3＋ ： Y2SiO5 powder and TiO2 powder）. Of which, as an upconversion luminescence agent, the Pr^3＋ ： Y2SiO5 can transform the visible light into ultraviolet light, satisfying the requirement of TiO2 for photocatalytic degradation. In addition, the photocatalytic mechanics of the degradation reaction was investigated.