| ZnO is a typical wide-bandgap,exciton-binding semiconductor material with excellent optical,electrical,mechanical and magnetic properties and is the most widely studied semiconductor material in recent years.In addition,ZnO materials also have a variety of morphologies,and their different shapes and sizes have different properties that can be applied in many fields.Among them,the hollow structure of ZnO microspheres due to its low density,large surface area and good stability and surface permeability,and its hollow part can accommodate a large number of guest molecules or large-size objects and other characteristics,which can have great potential applications in chemical,biological,optoelectronic and othfields.Therefore,the synthesis of monodisperse,size controllable ZnO hollow microspheres caused great attention of researchers.For now,most of the methods for preparing hollow microspheres have to go through some complicated physico-chemical processes.In addition,it is easy to produce by-products in the reaction process and the process is complicated and the preparation cost is high.Therefore,people are eager to make it through a simple process,low cost,green approach to prepare it.First of all,in this paper,a template carbon ball with good dispersibility and homogeneity was prepared by hydrothermal method.Then,as a template,ZnO hollow microspheres were prepared by chemical bath deposition(CBD)and impregnation method.ZnO hollow microspheres were successfully prepared by one-pot method using glucose,fructose and sucrose as carbon sources.According to the experimental fact and comprehensive analysis,ZnO hollow microspheres were finally selected by using starch as carbon source.The influences of the molar ratio of starch aqueous solution to zinc ion concentration and the heating rate on the morphology and structure of the product were analyzed.In addition,the formation mechanism of hollow microspheres is also analyzed.The crystal structure and morphology of the product were studied by XRD,SEM and TEM.The specific results are as follows:(1)In the process of preparing the carbon template by hydrothermal method using glucose,fructose,sucrose and starch as carbon sources,the experimental results show that under different experimental conditions,the carbon ball obtained with starch as carbon source has the best dispersibility and uniformity,and the diameter of carbon spheres is between 550 and 750 nm.(2)The preparation of ZnO hollow spheres by the chemical bath deposition method is an innovatively proposed method based on the related theoretical research of chemical bath deposition in this laboratory.However,after many experimental studies,after changing the experimental parameters,the ideal zinc oxide hollow micro sphere structure has not been obtained.(3)The carbon spheres prepared by hydrothermal method were used as templates to prepare ZnO hollow microspheres by impregnation method.The study found that hollow microspheres can be modified by changing the size of the template carbon spheres.The uniformity of the prepared ZnO hollow microspheres is better,but there is a certain agglomeration phenomenon.(4)ZnO hollow microspheres were successfully prepared by one-pot method using glucose,fructose,sucrose and starch as carbon sources.Among them,the structure of the spherical shell obtained from starch as the carbon source is the most complete,and the surface of the spherical shell has the smallest pores.Therefore,starch was selected as the carbon source to prepare ZnO hollow microspheres by one-pot method.The effects of molar ratio of starch aqueous solution and zinc ion concentration and heating rate on morphology and structure of hollow microspheres were studied.We found that when the concentration of starch aqueous solution remains unchanged,only changing the zinc ion concentration does not affect the particle size of the resulting microspheres,affecting the morphology and structure of the product.In addition,the growth mechanism of ZnO microspheres prepared by one-pot method was also analyzed. |
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