热分解碱式碳酸锌制备特定晶粒尺寸纳米氧化锌及机理研究

摘要

以硝酸锌和碳酸氢铵为原料,采用热分解碱式碳酸锌工艺制备纳米氧化锌.通过煅烧产物的XRD分析,确定了前驱体最佳热分解温度,得出了煅烧温度、时间与平均晶粒尺寸的关系.通过对不同煅烧温度产物的透射电镜微观形貌观察、分析,阐述了热分解纳米氧化锌的形成机理.实验结果表明,前驱体最佳热分解温度为200℃;在200～600℃的煅烧温度下可形成晶粒尺寸为8.4～29.3 nm的纳米氧化锌;纳米氧化锌平均晶粒尺寸与煅烧温度为指数函数关系,而与煅烧时间为幂函数关系;纳米氧化锌在热分解过程中,首先形成纳米孔,随后孔和孔连通形成纳米孔道,最后形成表面圆滑的棒状纳米氧化锌.%Nanometer zinc oxide was prepared by thermal decomposition of basic zinc carbonate with zinc nitrate and ammonium bicarbonate as raw materials.Through analysis of XRD spectrum of calcined product,the optimum temperature of decoposition was determined and function relationship of calcination temperature,time,and average grain size was obtained.The mechanism of thermal decomposition of nanometer zinc oxide was concluded through observation and analysis by TEM at different calcining temperatures.Results showed that the best thermal decomposition temperature of the precursor was 200 ℃;The average grain size of zinc oxide was in range of 8.4～29.3 nm at 200～600 ℃;There was a index function relation and power function relationship between average grain size of zinc oxide to calcining temperature and calcination time,respectively;During the process of thermal decomposing of basic zinc carbonate to zinc oxide,firstly nano pore formed,then holes connected to form nano channels,finally rod-like nanometer ZnO particles with smooth surface was got.