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采用浸渍-焙烧法制备了具有可见光响应活性的硅藻土/g-C_3N_4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Rh B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-C_3N_4复合材料对Rh B有较高的催化活性,光催化降解的速率常数是纯g-C_3N_4的1.9倍。自由基捕获实验表明,·O_2~–是Rh B在硅藻土/g-C_3N_4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-C_3N_4之间静电作用有利于光生电子-空穴在g-C_3N_4表面的迁移,进而提高g-C_3N_4的光催化活性。
Diatomite / g-C_3N_4 composite photocatalytic materials with visible light-responsive activity were prepared by impregnation-roasting method. The phase composition, morphology and optical absorption properties were characterized by TG, XRD, FE-SEM, HR-TEM, FT-IR, XPS, UV-Vis-DRS and PL spectra. The photocatalytic degradation of Rh B was used as a probe reaction to evaluate the activity of the catalyst. The photocatalytic results showed that 2.32wt% diatomite / g-C_3N_4 composite had higher catalytic activity for RhB, and the rate constant of photocatalytic degradation was 1.9 times that of pure g-C_3N_4. Free radical trapping experiments show that · O 2 ~ - is the main active species of Rh B photocatalytic degradation on diatomite / g-C 3 N 4 composites. The main reason for the increase in photocatalytic activity is that the electrostatic interaction between diatomaceous earth and g-C_3N_4 favors the migration of photogenerated electron-hole on the surface of g-C_3N_4, which enhances the photocatalytic activity of g-C_3N_4.