纳米α-Fe_2O_3的热解法制备及催化性能

以Fe(NO_3)_3·9H_2O为主要原料,采用醇盐液热解法结合超临界流体干燥技术制备纳米α- Fe_2O_3微粉。用XRD,TEM对样品进行表征,重点考察热解法制备工艺对α-Fe_2O_3晶态、形貌和尺寸的影响,并通过CO与NO的反应来测试其催化活性,探讨其在汽车尾气净化催化中的应用。结果显示,用醇盐液热解法结合超临界流体干燥技术制备出疏松且分散度较好的红色纳米α-Fe_2O_3粉；该方法制备工艺简单,操作方便,能有效地防止纳米材料制备过程中的硬团聚现象；纳米α-Fe_2O_3对汽车尾气中的主要有害成分NO_(?)有较好的催化净化效果,在500～600 K这一温度范围,NO转化率趋近100%。

Preparation of nanometer a-Fe2O3 by heat decomposition method and its catalytic performance

The nanosizedα-Fe_2O_3 particles are prepared by heat decomposition and supercritical fluid drying technology with pure Fe (NO_3)_3·9H_2O as main materials,and characterized by XRD and TEM.The key purpose is to investigate the effects of preparation conditions on crystal shape,appearance and size ofα-Fe_2O_3,then through the chemical reaction of CO and NO to check the catalytic activity and to discuss its use in catalysis of purification of automobile exhaust.The results show as follows:(1)the method which is sim- ple and convenient is effective in producing red and distributed nanos- izedα-Fe_2O_3 particles;(2)supercritieaI fluid drying technique can ef- fectively resolve the problem of conglomeration when the nanosized -Fe_2O_3 particles is prepared;(3)The nanometerα-Fe_2O_3 particles have certain catalytic activity,it can be used as a kind of catalyst to purify automobile exhaust such as NO_x.The transformation rate of NO is higher at 500——600 K.