Synthesis And Physical Properties Of Ag/Cu₂O Composite Nanostructures By Laser Chemical Method

Cuprous oxide?Cu₂O?is an important p-type direct bandgap semiconductor with a band gap of 2.17 eV.It has high absorption coefficient in the visible light region,and has been attracting increasing attention in the recent years due to its important applications in the field of photocatalysis,photovoltaic solar cells,and photoelectricity sensing.The combination of localized surface plasmon resonance?LSPR?characteristics of metal nanostructures with Cu₂O,not only can promote electron transfer by schottky barriers and suppress the recombination of carriers,but also can create novel synergistic interactions.The conventional synthesis methods of metal and oxide composite nanomaterials have the problems of operational complexity,time-consuming,and environmental pollution.In contrast,laser chemical methods have the advantages of operational simplity,short period,and environmental friendliness.In this paper,a variety of morphologies of Cu₂O nanostructures and Ag NW/Cu₂O core-shell structures were synthesized via laser chemical method.We discussed the morphology evolution of Cu₂O nanostructures with the change of photo-chemical reaction rate,and explored the enhancement of the photochemical reaction by the LSPR field enhancement effect of the Ag NWs.The main results are as follows:1.Cu₂O nanoparticles were synthesized via irradiating the copper acetate solution with the ultraviolet pulse laser.We controlled the size of the Cu₂O nanoparticles by adjusting the irradiation energy densities.According to the infrared spectra,we demonstrated that electron transfer from ligand to metal ions in copper acetate molecule after irradiation is the reason for the reduction of copper acetate to Cu₂O.2.After the ethylene glycol was added to copper acetate solution,we found that the morphology of the Cu₂O changed from nanoparticles to flowers,tripods,and finally returned to nanoparticles by increasing the irradiation energy density.By observing the evolution of Cu₂O nanostructures by increasing the irradiation time,we investigated the growth process of the Cu₂O nanostructures,and found that the morphology of the Cu₂O nanostructures was related to the molecular structure and the selective adsorption of the ethylene glycol.3.We utilized the LSPR field enhancement effect of the Ag NWs to promote the photochemical reaction rate of our laser chemical method.We achieved a rapid and dense deposition of Cu₂O nanoparticles on the Ag NW surfaces,and synthesized Ag NW/Cu₂O core-shell structures.The SEM was used to demonstrate the inhibitory effect of surfactant?PVP?on the agglomeration of Cu₂O particles,and the layered growth of Cu₂O along the Ag nanowires was achieved.Then,a dense and uniform Ag NW/Cu₂O core-shell structure was obtained.With the increase of laser irradiation time,the shell thickness of the Ag NW/Cu₂O core-shell structure increased.We obtained Ag NW/Cu₂O core-shell flower structure by adding ethylene glycol.Finally,the photocatalytic performance of the Ag NW/Cu₂O core-shell structures was preliminarily verified.