Preparation Of Zinc-based Nanomaterials By Lyotropic Liquid Crystal Template Method

Zinc-based II-VI compound semiconductors are an important class of direct wide band gap semiconductors,and zinc oxide and zinc sulfide are representative of them.Compared with other important wide bandgap semiconductors,it has large exciton binding energy and excellent permeability in visible to far infrared.It is widely used in photocatalysis,photoresistors,sensors and other fields.The template method is a simple and efficient method for preparing zinc-based compounds.In many templates,lyotropic liquid crystals are used as a soft template.Because the template structure is controllable and easy to remove,the shape and shape of the particles can be changed by changing the template.Appearance and specific surface area have become an influential research direction for the preparation of nanomaterials.In this paper,the lyotropic liquid crystal template of SDS/C5H11OH/H2O ternary system was constructed by using layered lyotropic liquid crystal as template to prepare zinc-based compounds.The influence of the proportion of each component on the lyotropic liquid crystal phase was investigated.According to the POM diagram,when SDS:C5H11OH=5:5,the mass of water accounts for 50%of the total mass,the typical cross pattern texture of the lamellar liquid crystal appears,and the distribution is very uniform,and the cubic liquid crystal phase is excluded by XRD.Interference,so the ratio is chosen to construct a lyotropic liquid crystal template.The lyotropic liquid crystal system was constructed by using different concentrations of zinc nitrate solution and precipitant instead of water.The effect of the concentration of nitric acid solution and the type of precipitant on the lyotropic liquid crystal phase was investigated.The interference of cubic liquid crystal was excluded,and the concentration of zinc nitrate solution was determined to be 0.5 mol/L,ammonia water is used as a precipitant to construct a lyotropic liquid crystal,and this is used as a template to prepare nano ZnO.The nano-ZnO is a hexagonal wurtzite structure with high purity and a specific surface area of 29.79 m2/g,which is significantly larger than the specific surface area of the template-free ZnO(12.37 m2/g),and the forbidden band width is 3.22 eV,compared with The template-free ZnO(3.37eV)was significantly reduced,and the methylene blue in the solution was degraded under ultraviolet light irradiation.The degradation rate reached 89%after irradiation for 150 minutes,which was obviously better than that of the template-free ZnO particles.The lyotropic liquid crystal was formed by replacing the water with 0.5 mol/L zinc nitrate solution,and the sodium sulfide solution was added dropwise to the lyotropic liquid crystal to prepare nano-ZnS particles.By characterizing and analyzing,the obtained nano-ZnS was spherical particles with higher purity and specific surface area.It is 32.79m2/g and the forbidden band width is 3.1eV.Compared with the non-template ZnS,the specific surface area is obviously increased,and the forbidden band width is obviously reduced.After 150min irradiation under ultraviolet light,the photocatalytic degradation rate of methylene blue reaches 90%,with strong photocatalytic performance.