2D TiO2/Ag3PO4异质结复合催化剂的制备及其光催化性能研究

采用溶剂热法制备了二维TiO₂纳米片（2D TiO₂），然后通过原位生长法在其表面沉积Ag₃PO₄，得到2D TiO₂/Ag₃PO₄异质结复合光催化材料。通过透射电子显微镜（TEM）、扫描电子显微镜（SEM）、X射线衍射（XRD）、紫外可见分光光谱法（UV-Vis）、X射线光电子能谱（XPS）、N₂吸附-脱附法（BET）等手段对催化材料进行了表征，评价了2D TiO₂/Ag₃PO₄在可见光下催化降解罗丹明B （RhB）的性能，并结合荧光和电化学测试结果，提出了2D TiO₂/Ag₃PO₄的可见光催化机理。结果表明，2D TiO₂/Ag₃PO₄的吸附-光催化降解性能随着Ag₃PO₄含量的增加而提高；少量H₂O₂可以极大地提高2D TiO₂/Ag₃PO₄的光催化活性；光催化降解RhB过程中的主要活性物质是·OH和·O^-₂，异质结的存在使2D TiO₂/Ag₃PO₄具有比2D TiO₂更优异的光催化活性、电荷分离能力和更快的光电子转移速率。

Preparation and photocatalytic performance of 2D TiO2/Ag3 PO4 heterojunction composite catalyst

Heterostructured 2D TiO₂/Ag₃PO₄ photocatalysts have been synthesized by in situ growth of Ag₃PO₄ on the surface of two-dimensional TiO₂ nanosheets (2D TiO₂) prepared by a solvothermal method. The 2D TiO₂/Ag₃PO₄ photocatalyst was characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), ultraviolet-visible spectroscopy (UV-Vis), X-ray photoelectron spectroscopy (XPS), and N₂ adsorption-desorption measurements (BET). The photocatalytic degradation performance of the 2D TiO₂/Ag₃PO₄ photocatalyst was evaluated using rhodamine B (RhB) as a probe material. The results indicated that the adsorption-photocatalytic degradation performance of 2D TiO₂/Ag₃PO₄ was enhanced by increasing the content of Ag₃PO₄, and that a small amount of H₂O₂ can greatly improve the photocatalytic activity of 2D TiO₂/Ag₃PO₄. Capture experiments of active substances indicated that ·OH and ·O^-₂ free radicals are the main active oxidizing species involved in the RhB photoreaction process. Based on the results of fluorescence and electrochemical tests, a mechanism for the visible light photocatalytic degradation of RhB using 2D TiO₂/Ag₃PO₄ has been proposed. As a result of the formation of heterojunctions between 2D TiO₂ and Ag₃PO₄, 2D TiO₂/Ag₃PO₄ had better photocatalytic activity, more efficient photocarrier separation and higher transfer efficiency than 2D TiO₂ under visible light irradiation.