Preparation Of ZnO Nanowire Array And Photo Electrochemical Performance

ZnO has excellent optical, mechanical and thermal performance and can be widelyapplied in solar cell, photocatalytic degradation of organic matter, transparent transistorsand UV emission and detecting device. It has become an effective way to employsemiconductor photocatalysis to degrade organic pollutants in water, therefore solvingthe environmental pollution humans are faced with. Nano-ZnO has low cost, variedmorphologies, and good adsorption properties. Nano-ZnO also has the features of arelatively large exciton binding energy and high electron mobility, making it easy toform a nanowire. Therefore, Nano-ZnO proves to be an effective semiconductorphotocatalyst to degrade organic pollutants. However, there still exist some problemswhen it comes to application. In order to improve the optical performance of Nano-ZnO,it should be modified to achieve higher quantum efficiency, inhibit compound carriers,expand its range of light response, enhancing its absorption in the visible or infraredband. This is the major approach as well as the focus of research. This research adoptsthe electrochemical deposition method to prepare ZnO nanowire structures. Technicssuch as SEM and XRD are applied to study the effect of impurity ions and itsmechanism in the electrolyte of nano ZnO morphology. This research also attempts touse methods of vulcanization and coating to modify the performance of ZnO nanowire.And the degradation of methyl orange reagents is for the characterization study of thecatalytic properties of ZnO photoelectric.During the preparation of ZnO nanowires through electrochemical depositionmethod, different concentrations of Pb2+ions are added to the electrolyte. The resultsindicate that Trace (10-6) of Pb2+in the electrolyte can not only improve their orientation,but also significantly increase ZnO nanowires density, while producing only a few flaws;When Pb2+content continues to grow, more impurities and defects will be introduced,thus having a greater impact on its performance; Add15%concentration of Li+in theelectrolyte, there will be a large area of lodging, uneven thickness, surface full ofdefects and velvet-like attachments; When different concentrations of Mg2+are added tothe electrolyte, petal-like clusters of ZnO nanowires are formed, and the center has thepattern of a two-dimensional periodic petal. This trend becomes increasingly apparentwith increase of Mg2+concentration.To study the effects of sulfide on the catalytic properties of ZnO nanowires, purenano-ZnO is put in the Na2S solution under the constant temperature of60°C.Thereaction respectively lasts0.5/1/2/3/5/10h. The SEM and XRD patterns show thatduring the process fine lines and cracks are produced because of dissolution. With theincrease of curing time, ZnO nanowires even break, exposing the new plane. Under the illumination of xenon lamp (to simulate natural lighting conditions), ZnO nanowireswith different curing time will serve as catalysts for the degradation of methyl orangesolution. The results demonstrate that the catalytic degradation rate improves with thevulcanization of Nano-ZnO. Within a certain time range, the longer the curing time, thebetter the photocatalytic performance.Then the ZnO nanowires work as the cathode and deposited Mg(OH)2on itssurface. Through successive chemical bath deposition method, the ZnO nanowires arecoated PbS. Results suggest that the performance of Mg(OH)2-deposited ZnO becomesbetter, and that the photocatalytic properties of PbS-coated nano-ZnO are higher thanbefore the modification, and that the higher the degree of modification, the better thephotocatalytic performance.