Study On Support And Composite Modification Of Silver Carbonate Photocatalytic Materials

Solar photocatalytic materials can not only hydrolyze water to produce hydrogen,but also convert greenhouse gas carbon dioxide into clean renewable energy.Photocatalytic materials can also use light-generated electrons or holes in the conduction band valence band to lighten organic pollutants in water into small molecules such as non-toxic water and carbon dioxide.In recent years,due to the increasing pollution of water bodies,the application of photocatalysis technology in the treatment of organic pollutants in water bodies is green and environmentally friendly,so it has been more and more paid attention by scientific researchers.Among the many photocatalytic materials,silver carbonate photocatalytic materials have attracted wide attention from researchers due to their narrow band gap and good photocatalytic degradation effect under visible light irradiation.On the one hand,Photo-generated electrons are easy to recombine with photo-generated holes,when silver carbonate photocatalytic materials are exposed to visible light.On the other hand,silver carbonate is slightly soluble in aqueous solution,which is easily reduced to metallic silver by photo-generated holes,resulting in a decrease in photocatalytic activity and stability.Moreover,there is the problem of difficulty in powder recovery after the reaction of the silver carbonate photocatalytic material.In order to improve the above disadvantages of a single silver carbonate photocatalytic material,the main research contents of this master thesis are as follows:Firstly,the combination of graphene oxide silver carbonate photocatalytic material can effectively facilitate the separation of photo-generated electrons and holes,thereby suppressing the occurrence of photocorrosion and improving the activity of silver carbonate photocatalytic material.We facile fabricate a ternary composite photocatalytic material of silver carbonate,silver bromide and graphene oxide by a simple one-pot co-precipitation method.The photocatalytic activity of graphene oxide silver carbonate and silver bromide ternary composite photocatalytic materials for the degradation of rhodamine B?Rh B?and phenol under visible light.The optimized composite photocatalytic material of silver carbonate,silver bromide and graphene oxide has the highest photocatalytic activity,whose the apparent reaction rate constant is 107 and 5.63 times higher than that of pure silver bromide and silver carbonate,respectively.The excellent photocatalytic properties of the photocatalytic composites of silver carbonate,silver bromide and GO are mainly attributed to their heterogeneous structure and strong light absorption capacity,which can promote the effective separation of photogenerated electron-holes.Free radical capture experiments confirm that h⁺and·O₂^-are the main active substances that degrade organic pollutants.We believe that this ternary composite photocatalyst has a good application prospect in the purification of organic pollutants in wastewater.Secondly,the silver carbonate-based photocatalyst also has the disadvantages that it is difficult to separate,recycle and reuse the powder after the photocatalytic reaction.Photocatalytic materials fixed loading technology is one of the effective ways to solve the above problems.The compounding of silver carbonate titanium dioxide carbon cloth not only facilitates recovery and reuse of powder materials,but also stimulates the transfer of photo-generated electrons of silver carbonate,thereby improving the activity of the composite photocatalytic material.We prepared a composite photocatalytic material with silver carbonate,titanium dioxide and carbon cloth.Compared with carbon cloth silver carbonate and carbon cloth titanium dioxide,silver carbonate,titanium dioxide and carbon cloth composite photocatalytic materials exhibit higher photocatalytic activity for photodegradation of rhodamine B.This is because silver carbonate,titanium dioxide and carbon cloth composite photocatalytic material not only facilitates the photocatalytic material to respond under visible light,but also improves the efficiency of photo-generated electron and hole separation.This study provides new ideas for the modification of photocatalysts with fixed loading technology.Thirdly,in the above,titanium dioxide is used to grow on carbon cloth.Due to the large size of titanium dioxide,silver carbonate cannot grow well on carbon cloth titanium dioxide,thereby affecting the photocatalytic activity of the composite photocatalytic material.The molybdenum sulfide's flower-like structure can allow silver carbonate to be well supported on it.In this part,the molybdenum disulfide synthesized by hydrothermal method has a flower-like structure with good photoelectric performance and catalytic performanc.Combining it with silver carbonate material is also beneficial to the separation of photo-generated electrons and holes,which is beneficial to improving the activity of the composite photocatalytic material.In this experiment,we successfully prepared carbon cloth-supported molybdenum disulfide silver carbonate composite photocatalytic materials.Through photodegradation experiments of rhodamine B under visible light irradiation,it was concluded that carbon cloth supported molybdenum disulfide and silver carbonate have high photocatalytic activity and good recyclability.In addition,the carbon fibers in molybdenum disulfide provide high-speed charge transfer channels for photo-generated electrons,thereby reducing the recombination rate of photo-generated electron-hole pairs in silver carbonate materials and improving the composite photocatalytic activity.This can provide a new method for the application of photocatalyst powder recovery and the application of carbon cloth-supported composite photocatalytic materials in sewage treatment.