不同碱源制备纳米Co3O4及气敏性能研究

Gas sensing performance of nano Co3O4 synthesized with different alkali sources

采用微波辅助法,将硝酸钴分别与尿素、氢氧化钠、氨水反应,制备了不同形貌的纳米Co3 O4,并用SEM、XRD等方法对合成材料的形貌和结构进行了表征。研究了由不同碱源制得Co3O4气敏材料的气敏性能。结果表明:随着碱源碱性的提高,其形貌由小球状向纳米片转变,其响应灵敏度增加,响应时间降低。用氢氧化钠作碱源,制备的纳米Co3 O4在240℃时对体积分数100×10^-6的苯胺表现出了良好的选择性,其响应灵敏度可达6.6,响应恢复时间分别为31 s和290 s。

Co3O4 nanomaterials were prepared by microwave-assisted reactions of cobalt nitrate salts with urea,sodium hydroxide and ammonia respectively.The structures and morphologies of the samples were characterized by XRD and SEM techniques.Meanwhile,the gas sensing performances of the as-synthesized samples were also investigated.The results show that the morphologies of samples were changed from nano sphere to nano sheet as the alkalinity of alkali source increases,which accompany with enhanced responses and reduced response time.Co3O4 prepared by sodium hydroxide as the alkali source shows excellent selectivity of 100×10^-6 aniline at 240℃,whose response value can reach 6.6 and response/recovery time is 31/290 s respectively.