Microstructure Regulation Of Zinc Sulfide Based Photocatalytic Materials

The global crisis caused by environmental pollution and energy shortage has become a problem to be solved urgently.Great hopes are placed on the semiconductor photocatalysis technology due to the direct use of solar energy for pollution control and clean energy conversion.As a wide band gap semiconductor with direct bandgap,ZnS has attracted much attention owing to its higher photogenerated carrier yield and negative conduction potential.However,a relatively wide band gap restricts ZnS on the effective use of solar light,which has high photogenerate carrier yield but low separation efficiency,resulting in low light quantum efficiency.Therefore,microstructure regulation of ZnS based semiconductor photocatalyst is carried out in order to effectively narrow the band gap and improve the separation efficiency of photogenerated carrier.The ZnS based materials with high photocatalytic activity are constructed.and it can provide effective data support for the popularization and application of photocatalytic technology.In this study,ZnS based photocatalytic materials have been researched by means of controlling its microstructures and combining with grapheme in order to expand the spectral response range and improve the utilization rate of photogenerated carriers.The main research contents and results are as follows:(1)Zinc source(zinc chloride,zinc acetate,zinc citrate)and sulfur source(sodium sulfide,thiourea,2-mere apto acetic acid)were used as raw materials to synthesize flake,spherical and broccoli zinc sulfide using microwave hydrothermal method.And their photocatalytic performances were evaluated by degrading the organic compound RhB.The photocatalytic efficiency of degrading 10 mg · L-1 RhB reaches 100.0%in 150 min.The increase of active sites and size effect are the main factors to improve the photocatalytic performance.(2)Graphene oxide(GO)was prepared using improved Hummers method,and RGO/ZnS photocatalytic materials were prepared via in-situ hydrothermal reduction.In addition,effects of the amount of graphene oxide on photocatalytic performance of composites were investigated.The results show that the content of graphene has a great influence on the micromorphology of the product.When the content of graphene is 0.2%,the product is nano-agglomerate granular,and when the content of graphene is 1.00%the product is the microsphere composed of nano flake ZnS.The addition of graphene regulates the band gap of RGO/ZnS and increases its absorption in the visible light region.Compared with pure zinc sulfide,the photocatalytic efficiency of RGO0.2/ZnS is 41.2%higher than that of pure zinc sulfide.The effective adsorption of graphene and the excellent carrier mobility are the main reasons for the improvement of photocatalytic performance.