以二水合醋酸锌及氯金酸为主要原料,通过微波水热法快速合成ZnO及Au-ZnO.使用X射线衍射、扫描电子显微镜和透射电子显微镜对样品的组成及结构进行表征.研究发现,制备的材料具有中空微球结构,直径约为4μm.以制得微球构筑旁热式气敏元件,并采用静态配气法测试了不同掺金量的气敏元件对乙醇、甲醇、丙酮和氨气等气体的敏感性能.分析结果表明,小粒径的Au纳米粒子负载在ZnO表面,提高了表面的粗糙度和比表面积,除此之外,Au活化了乙醇分子,促进了乙醇和氧离子在表面的化学反应,导致Au负载的ZnO对乙醇具有灵敏度高、检测下限低、选择性好、响应和恢复迅速等优点.
ZnO and Au-ZnO hollow microspheres are synthesized with zinc acetate dihydrate and chloruronic acid by microwave-assisted hydrothermal method.The composition and structure of the samples are characterized by X-ray diffraction (XRD),scanning electron microscopy (SEM) and transmission electron microscopy (TEM).The results show that the prepared material has a hollow-microsphere structure with the diameter of about 4 μm.The microspheres are used to construct the directly-heated type gas sensor.The sensing properties of the gas sensors with different Au content are tested by static gas distribution method toward ethanol,methanol,acetone and ammonia,etc.The results show that the small Au nanoparticles loaded on the surface of ZnO increase surface roughness and specific surface area.Moreover,Au additives activate ethanol molecules and promote the chemical reaction of ethanol and oxygen icons on the surface.Therefore,Au-ZnO hollow microspheres exhibit high sensitivity,low limit of detection,good selectivity,rapid response and fast recovery.