不同形貌的ZnSn(OH)6的制备与气敏性能的应用

使用简易的流程,实验条件或设备,简单的制备方法制备出两种形貌的单分散ZnSn(OH)6(ZHS)微晶(MCs).利用X射线衍射(XRD),场发射电子显微镜(FESEM),透射电子显微镜(TEM),紫外可见吸收光谱(UV-Vis),比表面吸附(BET)等不同的测试手段对羟基锡酸锌(ZHS)微晶(MCs)的三维多级纳米结构(HAs)的形貌和结构进行了表征.通过控制所滴加氨水的浓度,反应体系中羟基锡酸锌的形貌可由立方形转变为球形.以羟基锡酸锌为气敏材料的传感器对甲醛有较好的气敏性.然而,和立方形羟基锡酸锌微晶相比,球形羟基锡酸锌微晶对甲醛表现出更高的灵敏度,更快的响应速度和良好的重现性.更重要的是,由于球形羟基锡酸锌微晶具有更多的氧空位缺陷,较小的带隙能和较大的活性表面积,球形羟基锡酸锌在600 nm左右表现出最优异的气敏性能.

Synthesis of shape-controlled ZnSn(OH)6 and gas sensing properties

Monodisperse ZnSn(OH)₆(ZHS) microcrystallites(MCs) with two morphologies have been prepared through a facile preparation method without complicated steps,advanced experimental conditions or equipments.The morphology and compositional characteristics of the 3D hierarchitectures(HAs) of ZHS MCs were investigated by various techniques such as XRD,FESEM,TEM,UV-vis spectra,BET.In the reaction system the morphology evolution from cube to sphere was controlled with adding different concentration of NH₄OH.The gas sensors based on ZHS exhibited a good gas sensitivity to HCHO.However,the gas sensors based on spherical ZHS MCs exhibited the higher sensitivity,shorter recovery time and good reproducibility to HCHO than those of cubic ZHS MCs.More importantly,it was found that spherical ZHS MCs with ~600 nm size had the best gas-sensing properties owing to more oxygen vacancy defects,less band gap energy,and larger active surface area.