Study On Visible-light Driven Photocatalyst Of Silver Bromide Modified By Metal Ions

The silver bromide?AgBr?nanoparticles were prepared by the static diffusion and ion exchange method with silver nitrate and sodium bromide as the main raw materials.The effects of the reactant concentration and the mixed mode,the dropping reaction time on the mean size of the silver bromide nanoparticles were investigated.The results show that the as-prepared silver bromide nanoparticles possess face centered cubic structure and the mean particle size is from 52.0 nm to 70.0 nm.The specific surface area of silver bromide nanoparticles is 5.8 times of the common silver bromide particles.The experiment results of photocatalytic degradation of methyl orange show that the as-prepared silver bromide nanoparticles possess excellent visible-light photocatalytic activity and stability for photodegradation of methyl orange compared with the common silver bromide particles,and the photocatalytic activity of the as-prepared silver bromide nanoparticles is 4.5 times to the common silver bromide particles.The silver bromide/superabsorbent acrylic polymer?AgBr/SAP?composite materials were prepared by in-situ ion exchange method with SAP as the template agent.Then H of-COOH on the molecular chainof SAP were exchanged with Fe³⁺and compounded by AgBr/SAP to obtain Fe³⁺/AgBr/SAP photocatalyst.The as-prepared Fe³⁺/AgBr/SAP photocatalyst were characterized by XRD,XPS,SEM,UV-vis DRS,element mapping and PL.The results show that the presence of Fe³⁺on the surface of the composite particles can obviously improve the absorbance of visible light and the electron-hole pair separation efficiency.The results of photocatalytic experiment show that the as-prepared Fe³⁺/AgBr/SAP photocatalyst possesses excellent visible-light photocatalytic activity and stability due to the modification of Fe³⁺on the surface of AgBr/SAP composite particles.The AgBr/TiO₂ mesopore materials were prepared by sol-gel,low temperature water bath and in-situ precipitation.Then the PVC/AgBr/TiO₂ composites were obtained by solvent evaporation method.Afterward,the PVC/AgBr/TiO₂ composites were heated at higher temperatures to form CPVC/AgBr/TiO₂ composite materials.The as-prepared composite materials were characterized by XRD,XPS,SEM,TEM,BET,UV-vis DRS,EIS,and PL.The results show that AgBr in the composite materials possess face centered cubic structure and TiO₂ possess typical anatase phase.The absorbance of visible light and the electron-hole pair separation efficiency of CPVC/AgBr/TiO₂ composite materials were significantly improved.The photocatalytic activities of AgBr/TiO₂ and CPVC/AgBr/TiO₂ composite materials are 6.6 and 13.0 times to pure TiO₂,respectively.Forethemore,The visible-light photocatalytic mechanism of the CPVC/AgBr/TiO₂ composite materials has been discussed.