硅藻土/g-C3N4复合材料的制备及其可见光增强活性

采用浸渍-焙烧法制备了具有可见光响应活性的硅藻土/g-C₃N₄复合光催化材料。利用TG、XRD、FE-SEM、HR-TEM、FT-IR、XPS、UV-Vis-DRS 和 PL谱等手段对其物相组成、形貌和光吸收特性进行表征。以RhB的光催化降解为探针反应评价催化剂的活性。光催化结果表明, 2.32wt%硅藻土/g-C₃N₄复合材料对RhB有较高的催化活性, 光催化降解的速率常数是纯g-C₃N₄的1.9倍。自由基捕获实验表明, ·O₂^-是RhB在硅藻土/g-C₃N₄复合材料上光催化降解的主要活性物种。光催化活性提高的主要原因在于硅藻土和g-C₃N₄之间静电作用有利于光生电子-空穴在g-C₃N₄表面的迁移, 进而提高g-C₃N₄的光催化活性。

Synthesis of Diatomite/g-C3N4 Composite with Enhanced Visible-light-responsive Photocatalytic Activity

Novel visible-light-responsive diatomite/g-C₃N₄ composite was successfully synthesized via a facile impregnation-calcination method. The sample was characterized by TG, XRD, FE-SEM, HR-TEM, FT-IR, XPS, UV-Vis-DRS, and PL spectra. The photocatalytic activities of samples were evaluated by degradation of RhB under visible light irradiation. Experimental results indicated that 2.32wt% diatomite/g-C₃N₄ composite exhibits high efficiency for the degradation of RhB. The photoreaction kinetics constant value is about 1.9 times as high as that of g-C₃N₄ under visible light irradiation. The radical trap experiments indicate that ·O₂^- serves as the main active species for the photodegradation of RhB over 2.32wt% diatomite/g-C₃N₄ under visible light irradiation. The enhanced photoactivity is mainly attributed to the electrostatic interaction between g-C₃N₄ and negatively charged diatomite, synergistic effect lead to the efficient migration of the photogenerated electrons and holes of g-C₃N₄.