Ag-P改性g-C_(3)N_(4)的可见光催化活性研究

Study on visible light catalytic activity of Ag-P modified g-C_(3)N_(4)

以三聚氰胺、磷酸氢二铵和硝酸银为原料,采用热聚合法合成了Ag-P改性的复合可见光催化剂Ag-P/g-C_(3)N_(4),采用X射线衍射(XRD)、傅里叶变换红外光谱(FT-IR)、荧光光谱(PL)等对Ag-P/g-C_(3)N_(4)催化剂进行了表征与分析。通过Ag-P/g-C_(3)N_(4)存在下亚甲基蓝(MB)的可见光降解实验,系统研究了该类催化剂的可见光催化活性。结果表明,Ag-P复合改性没有明显改变g-C_(3)N_(4)的晶型结构,但是显著抑制了光生电子和空穴的复合,提高了其可见光催化降解活性。经过120 min可见光照射后,Ag(2%)-P/g-C_(3)N_(4)的速率常数达到0.00816 min^(-1),是原始g-C_(3)N_(4)的2.1倍,是P/g-C_(3)N_(4)的1.7倍。同时,探索了Ag-P/g-C_(3)N_(4)的可见光催化降解反应机制和循环使用稳定性。

Ag-P/g-C_(3)N_(4),a composite visible light catalyst modified by Ag-P,was synthesized via the thermal polymerization among melamine,diammonium hydrogen phosphate and silver nitrate.The yielded catalyst was characterized and analyzed by X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FT-IR)and photoluminescence spectroscopy(PL).The visible light catalytic activity was systematically measured in visible light-triggered degradation experiments of methylene blue The results showed that the modification of Ag-P composite did not significantly change the crystal structure of g-C_(3)N_(4),but greatly inhibited the recombination of photogenerated electrons and holes,thus improving its visible light catalytic activity.After 120 min of visible light irradiation,the rate constant of degradation catalyzed by Ag(2%)-P/g-C_(3)N_(4)reached 0.00816 min^(-1),which was 2.1 times that by the original g-C_(3)N_(4)and 1.7 times that by P/g-C_(3)N_(4).In addition,the visible light catalytic degradation mechanism and recycling stability of Ag-P/g-C_(3)N_(4)were explored.