Study On Preparation,characterization And Properties Of Novel Photocatalysts With Excellent Visible Light Photocatalytic Properties

Visible light-responsive photocatalytic technology holds great potential in water treatment to enhance purification efficiency,as well as to augment water supply through the safe usage of unconventional water sources.This thesis is aimed at the existence problem in photocatalytic technology,such as low photocatalytic efficiency and low solar utilization rate.The target is to develop the novel composite photocatalyst with visible light response.The details are summarized briefly as follows:1.This chapter summarizes the recent progress in the design and fabrication of visible light-responsive photocatalysts via various synthetic strategies,including the modification of traditional photocatalysts by doping,dye sensitization,or by forming a heterostructure,coupled with p-conjugated architecture,as well as the great efforts made within the exploration of novel visible light-responsive photocatalysts.Background information on the fundamentals of heterogeneous photocatalysis,the pathways of visible light-responsive photocatalysis,and the unique features of visible light-responsive photocatalysts are presented.The photocatalytic properties of the resulting visible light-responsive photocatalysts are also covered in relation to the water treatment,i.e.,regarding the photocatalytic degradation of organic compounds and inorganic pollutants,as well as photocatalytic disinfection.Finally,this review concludes with a summary and perspectives on the current challenges faced and new directions in this emerging area of research.2.A new environmental-friendly non-metallic g-C3N4/SiC composite photocatalyst was prepared by high temperature calcination.The structures of composite photocatalyst were characterized,and the photocatalytical activity was investigated by degradation of malachite green(MG)under visible light irradiation.Results showed that the composite catalyst for the degradation of MG possessed high efficiency.Its high photocatalytic efficiency is due to g-C3N4 in situ growth on the surface of SiC,formation of clusters of structure,which can fully contact betweenphotocatalyst and pollutant.It can be able to further enhance the visible light absorption,promote the excitation light to produce carrier,and effectively inhibit electron-hole recombination,and improve the separation efficiency,thus enhance the photocatalytic performance of the photocatalyst.3.A series of Ag base plasma photocatalysts were prepared by the light reduction and the hydrothermal method in acidic and alkaline conditions,respectively.Structures were characterized and the photocatalytic performance was tested by the degradation of methylene blue.It found that the visible light photocatalytic activity improved to different extent.Especially,the photocatalysts prepared by light reduction method under the condition of alkaline have the highest photocatalytic activity.The advantages of this kind of photocatalyst is a combination of a variety of components,including visible light activity,adsorption,electron transfer and separation ability.