Photochemical Characteristics And The Rhodamine Degradation Property Of Graphene/BiVO₄/CdS

Common semiconductor materials,such as TiO₂,ZnS and ZnO,have wide bandgaps of about 3.0 eV and can only absorb 5%of the solar ultraviolet light,46%of the visible light can not respond to light energy utilization efficiency is very Low,thus developing a semiconductor material that responds to visible light.CdS is a narrow bandgap semiconductor material with a bandgap width of 2.4 eV at room temperature.It is an n-type semiconductor that responds to visible light and has excellent optical and electrical properties.Due to its poor structural stability,CdS can easily erode.Therefore,to improve the light stability of CdS material and reduce the dissolution of Cd?II?is a necessary step to the application of CdS in environmental protection.This article aims to explore ways to effectively improve CdS stability and photoelectric conversion efficiency.The main research contents and achievements are as follows:?1?the photoactivity and anticorrosion of CdS coated with grapheneCdS particles were deposited on the surface of FTO conductive glass by a simple one-step hydrothermal method.The diameter of the particles was about 200 nm.The GO and r-GO sheets were modified on the surface of CdS by dipping-lift film formation method.The photoelectric response and stability test results show that both GO and r-GO modification have improved the photoelectric and photocorrosion resistance of CdS,which are increased to 1.73 and 1.47 times that of pure CdS electrode respectively.However,in the absence of sacrificial agent,the photocorrosion of CdS was inevitably happened.In the presence of sacrificial agents,after 3600 s irradiation of simulate natural light,the average diameter of the CdS particles is 135.4 nm,and the electrode stability was obviously improved.?2?modification of BiVO₄/CdS composites by graphene.We combined CdS with BiVO₄ with higher valence band to improve the overall oxidizing ability of the material and maintain the photo-electric stability of the material in the absence of sacrificial agents.We have constructed two types of semiconductors,"Type II"and"Z",by using two deposition sequences.In the process of their preparation,doping and surface modification are two different methods of modification.The stability of the electrode and the dissolution of Cd?II?resulted in a composite electrode with 99%light stability at 1000 s without dissolution and no Cd?II?dissolution.?3?improvement of photocatalytic activity of graphene on BiVO₄/CdS compositesThe CdS-GO/BiVO₄-GO composite photocatalytic materials were prepared based on the visible light response degradation characteristics of CdS materials and the adsorption properties of GO.The TEM observations showed that the GO sheet was successfully combined with CdS and BiVO₄ to form a ternary composite.Taking RhB solution as the target pollutant,it was found that CdS-GO/BiVO₄-GO has good visible light photocatalytic degradation ability and the degradation rate is as high as 95.22%.