【摘要】 过渡金属氧化物四氧化三钴(Co3O4)在CO氧化反应中展示了较好的低温活性.Co3O4催化剂用于富氢气氛下CO选择氧化反应已引起了人们极大的关注,具有潜在的应用前景.采用液相沉淀-热解氧化方法制备了2种不同形貌的纳米Co3O4.用X射线衍射(XRD)、扫描电子显微镜(SEM)等技术考察了包括沉淀剂种类、老化时间、焙烧温度等合成条件对生成Co3O4形貌、晶粒尺度的影响.制备的Co3O4的外形与沉淀前驱物外形直接相关.焙烧温度越高,Co3O4的颗粒越大.研究了制得的Co3O4在富氢气氛下CO选择氧化反应中的催化性能.对比以上方法制备的Co3O4的催化性能发现,催化剂的粒径和比表面积与催化剂的活性存在关联.使用尿素沉淀法并经250~300℃空气热解氧化制得的Co3O4具有较好的催化活性.更多还原

【Abstract】 The unsupported Co3O4 catalyst showed excellent low temperature CO oxidation activity.Its application for carbon monoxide preferential oxidation has attracted a great attention since it exhibited a potential prospect for industrial application.In this report,Co3O4 nanoparticles with two different kinds of morphologies were prepared by liquid-precipitation & air-oxidation pyrolysis method.In order to investigate the impact of preparation conditions(such as precipitating agents,aging time and calcination temperature) on the morphology and crystal size of Co3O4 nanoparticles,we used XRD,SEM to characterize the prepared Co3O4.Morphologies of Co3O4 are consistent with the morphology of their precipitation precursors.The higher the calcination temperature was,the larger the crystal size became.Catalytic preferential oxidation of carbon monoxide over Co3O4 nanoparticles in H2-rich gas was performed.We compared the catalytic performance of Co3O4 synthesized by above methods,found that size and surface area of the catalyst had correlation with its catalytic activity.The Co3O4 obtained by urea-precipitation & air-oxidation method calcination at 250～300℃ exhibits the best activity.更多还原