Co_3O_4纳米棒的制备及其对气相甲苯的催化氧化

Fabrication of Co_3O_4 Nanorods and Its Catalytic Oxidation of Gaseous Toluene

采用低温水热法制备棒状纳米结构的Co3O4,通过加入少量的表面活性剂(聚乙烯吡咯烷酮简称PVP),在95℃下低温反应,并调控制备过程的老化时间、溶液的pH这2个因素合成了棒状Co3O4纳米结构.X射线衍射(XRD)、透射电镜(TEM)表明制得的是呈立方晶体的Co3O4纳米棒,氢气程序升温还原(H2-TPR)、N2吸附脱附等表征手段表明老化时间和pH会影响Co3 O4纳米棒的尺寸、孔隙结构,进而影响其比表面积大小.采用气相甲苯作为目标物,运用气相色谱(GC)对Co3 O4的催化性能进行研究.结果表明在该实验中,调控老化时间和pH制得的Co3O4纳米棒只影响其低温降解效果,在温度低于260℃,活性最好的是pH=9,老化时间为12 h的催化剂;当温度高于260℃后,其降解曲线基本一致.

Co3O4 nanorods were fabricated by the low-temperature hydrothermal method.The Co3O4 nanorods were formed through adding a small amount of surfactants（Polyvinylpyrrolidone,referred to as PVP） and reacting at 95℃.Controlling the reaction time of preparation and pH of the solution can affect the properties of Co3O4 nanorods.X-ray diffraction（XRD）,transmission electron microscopy（TEM） proved the as-prepared samples were Co3O4 nanorods in cubic phase.Hydrogen temperature programmed reduction（H2-TPR） and nitrogen adsorption-desorption experiment results showed that the size and pore structure of Co3O4 nanorods could be affected by different reaction time and pH,and led to the difference in specific surface area.The catalytic properties of Co3O4 nanorods were examined by degradation of gaseous toluene.The results showed that conversion of toluene was affected under low temperature by Co3O4 nanorods,which were prepared by different reaction time and pH.When the temperature was below 260℃,the catalyst prepared in alkaline condition had the highest activity.However,when the temperature was higher than 260℃,the conversion of toluene was hot significantly different.