Research On Ag₃PO₄ Core-shell Structure Photocatalytic Performance

TiO₂ and CdS as an example of wide band gap and a narrow band gap photocatalysts,respectively,were widely studied.However,TiO₂ can only use a small amount of sunlight in the ultraviolet region of sunlight,while CdS increases the utilization of sunlight but has a high electron-hole recombination rate and serious photo-corrosion.Ag₃PO₄ has the advantages of high quantum efficiency and high activity,but its instability limits the practical application.Many methods are reported to mitigate the photo-corrosion by doping and modification about Ag₃PO₄.In recent years,the conductive compounds have been gradually introduced into the field of photocatalysis because of their good charge-transporting properties.Among them,7,7,8,8-tetracyanoquinodimethane?TCNQ?and polythiophene?P3HT?all have excellent ability and stability to conduct electrons or holes.The composite photocatalyst Ag₃PO₄@TCNQ,Ag₃PO₄@P3HT with core-shell structure was synthesized by simple method,and the SEM,TEM and FT-IR were used to detect the existence of P3 HT in the composite catalyst and confirm the structure of composite catalyst.The photocatalytic activity of the samples was studied by degradation of organic pollutants phenol and BPA under visible light irradiation.The degradation rate of Ag₃PO₄@TCNQ?0.3 wt.%?to degradation phenol achieved almost 100%in 12 min,which was about 23%higher than that of pure Ag₃PO₄.In addition,TCNQ wrapped on Ag₃PO₄ surface,as the core's protective layer,can effectively improve its stability.After five cycles,the degradation rate still reached 90%,but monomer stability retained only 43%.TCNQ,as a good electron acceptor,can transfer electrons from Ag₃PO₄ surface well,reduce the reduction of Ag⁺,greatly improving photocatalytic activity and stability.When the compound amount of P3 HT was 0.07 wt.%,the photocatalytic activity was the highest,and the degradation of phenol increased by about 23%compared with Ag₃PO₄,the degradation of BPA increased by about 25%.Using the conductive compound with a good transport elect rons as a composite catalyst shell,it exhibits higher photocatalytic activity for the degradation of phenol and BPA.It can effectively separate e^-/h⁺and inhibit the recombination of photogenerated e^-/h⁺pairs,which is the reason for the increase of photocatalytic activity and stability.