磷掺杂的介孔石墨相氮化碳光催化降解染料

将三聚氰胺、三聚氰胺聚磷酸盐和SBA-15热共聚成功制备了磷掺杂的介孔石墨类氮化碳（P-mpg-C₃N₄），并通过场发射扫描电子显微镜（FESEM）、X射线衍射光谱（XRD）、傅里叶转换红外光谱（FT-IR）、X射线光电子能谱（XPS）、场发射扫描透射电镜能谱（EDS）和紫外可见光漫反射光谱（UV-vis-DRS）等方法对催化剂形貌结构和光学性能进行了表征.结果表明，磷元素成功地掺杂在氮化碳的结构上，呈均匀分布，相对于石墨相氮化碳（g-C₃N₄），其比表面积可达198.3m²/g，并因此提供大量的活性位点而提高光催化活性.P-mpg-C₃N₄对亮丽春红5R的光催化降解速率是g-C₃N₄的31.3倍，其光催化性能增强的机理是禁带宽度的减小，可见光吸收范围从440nm延伸到了460nm，其次，改性后的光催化剂能显著抑制光生电子空穴对的复合，从而有更多的活性点位以及活性物种能参与光催化反应过程.循环实验表明，经过5个循环降解后光催化性能仍保持在初始状态的91.67%，表明P-mpg-C₃N₄具有很好的光催化稳定性.

Study on the photocatalytic degradation of dyes by phosphorus doped mesoporous graphite carbon nitride

Phosphorus doped mesoporous graphite carbon nitride was successfully prepared by simple thermal copolymerization with melamine, melamine polyphosphate and SBA-15. Afterwards, its morphology and optical properties was characterized by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), scanning transmission electron microscopy (EDS) and ultraviolet-visible diffuse reflectance spectroscopy (UV-vis-DRS). The results showed that phosphorus element was successfully doped on the structure of carbon nitride, and distributed homogeneously on the structure of whole nanoporous material. Compared to g-C₃N₄, the specific surface area of P-mpg-C₃N₄ can reach 198.3m²/g. In this way, more active site was obtained for photocatalytic reaction. The photocatalytic degradation of brilliant ponceau 5R (BP-5R) in solution was studied under visible light irradiation. It was also found that the photocatalytic degradation rate of P-mpg-C₃N₄ is 31.3times that of g-C₃N₄. The relative mechanism was as following. On the one hand, the P-doping and fragmented mesoporous structure could effectively extend visible light absorption range from 440nm to 460nm. On the other hand, the separation of photo-generated electron-hole pairs had been promoted and the transfer of photo-generated electrons had been accelerated. In this way, more active species participation in photocatalytic reaction process. Besides, photocatalytic performance remained 91.67% of the original state after 5cycles, the results of these cyclic experiments reveal that synthesized photocatalyst had good photocatalytic stability.