[Synthesis, spectral analysis and photocatalysis of Ag/K4Nb6,O17 heterojunction catalysts].

K4Nb6O17 photocatalyst was successfully synthesized by low-temperature hydrothermal method with layer structure.Considering that a large number of hydroxyl(Nb—OH) and oxygen species(NbO,Nb—O-) exist on the surface of K4Nb6O17 synthesized by hydrothermal method,Ag(en)+2 precursors were employed to synthesize Ag/K4Nb6O17 heterostructure photo-catalysts with highly dispersed Ag.Photocatalytic performance evaluation results show that the photodegradation rate of MO for K4Nb6O17 was remarkably improved when a small amont of Ag was loaded.The best loading dose of Ag is 0.5 at%.Based on various characterizations results of XRD,FTIR,UV-Vis DRS,XRF and TEM,the photocatalytic mechanism of Ag/K4Nb6O17 heterostructure catalysts was illuminated in detail and the conclusions were drawn as follows:(1) K4Nb6O17 nanocrystals serve as electron and hole sources for degradation of an organic dye;(2) Ag nanoparticles on the surface of K4Nb6O17 nanocrystals act as a sink for the electrons,promote interfacial charge-transfer kinetics between the metal and semiconductor,improve the separation of photogenerated electron-hole pairs,and thus enhance the photocatalytic activity of Ag/K4Nb6O17 photocatalyst.