中空管状g-C3N4/Ag3PO4复合催化剂的制备及其可见光催化性能

采用化学沉淀法制备中空管状 g-C₃N₄/Ag₃PO₄复合催化剂。通过 X射线衍射(XRD)、扫描电子显微镜(SEM)、紫外可见漫反射光谱(UV-Vis DRS)和荧光光谱对其结构、形貌和光学性能进行了表征。结果表明：Ag₃PO₄纳米颗粒均匀地分散在中空管状g-C₃N₄表面，两者紧密结合形成异质结。研究复合催化剂在可见光照射下降解盐酸四环素(TC)的光催化活性。结果显示：复合催化剂在80 min内对TC的降解率为98%，其降解反应速率常数是纯相Ag₃PO₄的3倍。经过5次循环实验后复合催化剂对于TC的降解率仍保持87%，具有优良的循环稳定性。捕获实验表明空穴(h⁺)和超氧负离子(·O₂^ˉ)是光催化反应过程中的主要活性物种。根据能带理论，提出了复合催化剂异质结的Z型光催化机理。

Preparation and Visible Light Photocatalytic Activity of Hollow Tubular g-C3N4/Ag3PO4 Composite Catalyst

Hollow tubular g-C₃N₄/Ag₃PO₄ composite catalyst was prepared by chemical precipitation method. The structure, morphology, and optical properties of the composite catalyst were characterized by X - ray diffraction (XRD), scanning electron microscopy (SEM), UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS), and fluorescence emission spectroscopy. The results showed that Ag₃PO₄ nanoparticles can be uniformly dispersed on the surface of hollow tubular g-C₃N₄, and closely combined to form a heterojunction. The photocatalytic activity of the composite catalyst under visible light irradiation was studied by the degradation of tetracycline hydrochloride (TC). The results showed that the degradation rate of TC over the hollow tubular g-C₃N₄/Ag₃PO₄ composite catalyst was 98% within 80 min, and its degradation reaction rate constant was three times that of pure Ag₃PO₄. After five cycles, the degradation rate of TC by the composite catalyst maintained 87%, indicating excellent stability. The capture experiment showed that hole (h⁺ ) and superoxide anion (·O₂^- ) were the main active species in the photocatalytic reaction. Based on the energy band theory, the Z- scheme photocatalytic mechanism of g-C₃N₄/Ag₃PO₄ composite catalyst heterojunction was proposed.