Preparation And Photocatalytic Performance Of Graphene Aerogel Catalyst Embedded With Ag@ZnO

Photocatalysis using solar energy is widely considered as an important method to solve environmental pollution,and the preparation of highly active and stable photocatalysts has been the been the main research direction in this field.ZnO is recognized as an excellent photocatalyst for its low cost,high stability,excellent photocatalytic activity and low toxicity,but its wide band gap and rapid charge complexation,to a large extent,limit its practical applications.Besides,the powder photocatalysts are prone to irreversible agglomeration,leading to active site loss and low reusability in practical use.Graphene aerogel has excellent adsorption performance and fast electron transfer efficiency,and its composites with photocatalyst can not only improve the degradation performance of composite catalytic materials,but also effectively solve the practical use problems of powder photocatalysts.Therefore,this paper adopts a simple thermal decomposition method.Ag nanoparticles were deposited on the surface of ZnO and combined with r GA to form ternary composite aerogel.The specific research work and main findings of this paper are as follows:1.Nano-Ag modified ZnO(Ag@ZnO)catalysts were fabricated by loading small-size Ag particles on the surface of lamellar flower-like ZnO with a simple thermal decomposition method.It was found that the Ag@ZnO catalyst had significantly improved photocatalytic performance compared with pure ZnO.When the Ag loading was 3%,the best photocatalytic degradation performance was achieved,and the good photocatalytic activity was still maintained after five cycles.The diffuse reflection and fluorescence spectroscopy characterization showed that the Ag nanoparticles in the composite catalyst as a co-catalyst inhibited the electron-hole complex and effectively enhanced the utilization of visible light,thus improving the photocatalytic performance.2.Ag@ZnO with the best photocatalytic performance,was used as the photocatalyst,and the reduced graphene oxide aerogel was prepared into a composite aerogel(r GA-Ag@ZnO)by hydrothermal assembly.r GA-Ag@ZnO has the three-dimensional spatial network structure of the aerogel,and the Ag@ZnO particles were encapsulated into the graphene lamellae with a more uniform overall distribution.With the increase of the content of Ag@ZnO,the specific surface area of the composite aerogel decreased and the porosity also decreased,because excessive Ag@ZnO particles filled into the pore graphene skeleton and destroyed the spatial network structure.3.rGA-Ag@ZnO has both excellent adsorption performance and the best photocatalytic degradation performance compared to pure ZnO and Ag@ZnO,The degradation rate is about2.49 times that of the Ag@ZnO material.Photochemical tests showed that the improved photocatalytic performance is due to the rapid electron migration and transport of graphene in the three-dimensional porous network,which promotes the separation of electron-hole and prolongs the lifetime of photogenerated electrons.The adsorption capacity of r GA-Ag@ZnO decreased with the increase of Ag@ZnO loading,and the composite aerogel showed the strongest degradation ability when the photocatalyst Ag@ZnO loading was 10 mg.The good photocatalytic performance could still be maintained after five cycles.