微波辅助溶剂热合成In-Si共改性TiO_2的增强光催化性能

利用微波辅助溶剂热法合成了In-Si共改性的TiO2光催化剂.粉末X射线衍射(XRD)、激光拉曼(Raman)光谱、N2吸脱附(BET)、X射线光电子能谱(XPS)、光致发光(PL)光谱和紫外-可见漫反射光谱(UV-Vis DRS)等实验表明,尽管掺杂和改性后TiO2结晶度略有降低,但不影响光催化剂锐钛相的形成.Si掺杂入TiO2晶格使颗粒变小,比表面积变大.In不能进入TiO2晶格,在TiO2表面形成了In2O3.罗丹明B(RhB)降解实验显示,In-Si共改性TiO2表现出很高的紫外和可见光催化活性,Si:In:Ti的摩尔比为0.03:0.02:1的样品(IST-2)光催化活性最高,紫外光下3 min即可将RhB降解完全,可见光下120 min RhB降解率为97%,这是由材料的高表面积,In2O3-TiO2复合半导体之间高效电荷转移及染料敏化等共同作用所致.对于苯酚,光催化降解则相对缓慢,700 min内尚不能降解完全.

Microwave-Assisted Solvothermal Synthesis of In-Si Co-Modified TiO2 Photocatalysts with Enhanced Photocatalytic Activity

In-Si co-modified TiO₂ photocatalysts were synthesized via a microwave-assisted solvothermal method. The obtained materials were characterized by X-ray diffraction (XRD), Raman spectroscopy, N₂ addesorption (BET), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL) spectroscopy, and UVVis diffuse reflectance spectroscopy (UV-Vis DRS). The photocatalysts all exist in an anatase phase, despite the fact that the crystallinity slightly decreased upon modification of the TiO₂ photocatalysts. Si-modification resulted in smaller nanoparticles and larger specific surface areas. In-modification led to the formation of In₂O₃ on the surface of TiO₂, such that In cannot enter the TiO₂ lattice, contributing to efficient charge transfer between the coupled semiconductors In₂O₃ and TiO₂. Degradation of Rhodamine B (RhB) showed that In-Si co-modified TiO₂ photocatalysts can exhibit high photocatalytic activity under both ultraviolet and visible light. The highest activity was obtained for In-Si co-modified TiO₂ with an Si:In:Ti molar ratio of 0.03:0.02:1 (IST-2), with which RhB was completely degraded within 3 min under ultraviolet light and where 97% of RhB was degraded after 120 min under visible light. The improved photocatalytic activity of In- Si co-modified TiO₂ may be ascribed to synergistic effects between large surface area, efficient electron transmission at the In₂O₃-TiO₂ interface, and the dye sensation effect of RhB. Photodegradation for colorless phenol occurred at a much slower rate than that for RhB, and the phenol did not completely degrade within 700 min.