纳米线堆积的铁硅球体催化剂用于费托合成

摘要

以共沉淀法所制的工业铁硅球体催化剂(indus-FS)为原料,用改进的有机胺蒸气相传输转化法,得到了负载高分散铁的交织氧化硅纳米线球体催化剂(NW-FS),并用于费托合成反应.在所制纳米线催化剂中,原料催化剂中氧化硅在氧化铁诱导下成功地转变成纳米线交织微球载体,而氧化铁组分则高度分散在氧化硅纳米线上.用扫描电镜、透射电镜、X射线衍射、低温氮吸附、X射线光电子能谱和程序升温还原等方法对所得纳米线催化剂进行了表征.在费托合成中,纳米线铁硅催化剂由于其特殊的堆积结构所导致的低的扩散阻力和高的铁活性组分分散度,提高了低碳烯烃尤其是乙烯的选择性.纳米线铁硅催化剂上低碳产物(C2-C4)的烯烷比为3.3,高于母体工业催化剂的1.9.%A catalyst consisting of SiO2 nanowires and highly dispersed Fe2O3 (denoted NW-FS) was synthe-sized in situ by iron-assisted amine-vapor-transport treatment. NW-FS was prepared by the direct transformation of an industrial spherical Fe2O3/SiO2 catalyst (denoted indus-FS). NW-FS was char-acterized by scanning electron microscopy, X-ray diffraction, transmission electron microscopy, N2-sorption measurements, X-ray photoelectron spectroscopy, and temperature-programmed re-duction. NW-FS exhibited a high selectivity for light olefins, especially for ethene in the Fischer-Tropsch synthesis. This was because of the highly dispersed Fe2O3 and low diffusion resistance of its open structure. The C2-C4 olefin/paraffin ratio was 3.3, which was higher than that of indus-FS at 1.9.