Synthesis And Photocatalytic Properties Of Fe Doped Ag-ZnO Nanocomposites

With the rapid growth of global economy,science and technology,the prevention of water pollution and discovery of new energy sources is urgently needed.From last decade,The extraordinary photocatalysis activity make ZnO draws more attentions.ZnO can degrade organic dyes which are difficult to decompose into CO₂ and H₂O in normal environment.In this study,Fe-doped Ag-ZnO nanocomposites were prepared by polymer network gel method.X-ray powder diffraction?XRD?,scanning electron microscopy?SEM?and transmission electron microscopy?TEM?characterization techniques were used to demonstrate the physical and chemical properties of synthesized nanoparticles.The optical properties of the sample were performed by means of photoluminescence spectroscopy?PL?and ultraviolet-visible absorption spectrum?UV-vis?.The photocatalytic activity was analyzed by combining the characterization results.In this work,the following objectives were achieved:1.Fe-doped Ag-ZnO nanopowders were successfully synthesized by one-step polymer-network gel method,where the XRD and SEM characterization show that Fe doping improves the dispersion of Ag nanoparticles and simultaneously reduce the grain size of ZnO.The XPS spectrum shows the increase of the Fe doping concentration,which lead to the coexistence of divalent and trivalent Fe,resulting in strong absorption in blue light frequency.Among all samples fabricated by normal synthesis method,Zn_0.96Fe_0.01Ag_0.03O exhibits the highest photocatalytic activity.2.Based on the previous research,the two-step polymer network gel method was used to obtain better photocatalytic activity Fe-doped Ag-ZnO nanopowders.XRD results show the grain size of the sample decreases by increasing the Fe doping concentration.TEM evidence the Ag-ZnO heterostructure formation among all samples.With the increase of Fe doping concentration,the bandgap shrink first and then increases.As observed from XPS,the Fe²⁺to Fe³⁺transition were enhanced by raising the Fe doping concentration,leading to the limitation of zinc interstitial?Zni?site in ZnO and weakening the blue emission?425 nm wavelength?.Zn_0.968Fe_0.002Ag_0.03O shows the best photocatalytic activity among all samples,indicating the optimal proportion of Fe²⁺and Fe³⁺can greatly improve the photocatalytic performance of Ag-ZnO.3.The microstructure and photocatalytic properties of ZnO samples were studied when the total percentage of Fe and Ag was kept at 3%.XRD and TEM results show that the heterojunction structure of Ag-ZnO are still exists.TEM result shows that the ZnO powder has a grain size distribution between 27.4 nm and 41 nm.PL founds that Ag loaded can increase the ultraviolet light intensity of ZnO,while a certain amount of Fe and Ag co-doping can reduce the luminous intensity of visible light.UV-vis reveals that the ZnO absorption intensity decreased with the increase of Fe doping concentration and decreases with Ag loaded.Zn_0.97Fe_0.005Ag_0.025O increases the absorption capacity of ZnO in the visible region due to the narrowest bandgap.The photocatalytic property of Zn_0.97Fe_0.005Ag_0.025O is the best when MB was degraded under the simulated sunlight.Based on the structural and optical analysis,the synergistic effect of?Fe,Ag?incorporation is suggested to improve the photocatalytic performance of ZnO.