高比表面积介孔TiO2的制备及负载钴基催化剂费-托合成反应性能研究

以钛酸四丁酯和异丙醇钛为钛源,CTAB和Brij56为表面活性剂,采用水热合成法制备出2种高比表面积介孔二氧化钛载体TiO2-B和TiO2-C.以商业P25(TiO2-P)为参比载体,采用满孔浸渍法制备了钴基费-托合成催化剂,利用氮气物理吸附-脱附、透射电子显微镜(TEM)、扫描电子显微镜(SEM)、原位X射线粉末衍射(in-situ XRD)和H2-程序升温还原(H2-TPR)等表征手段研究了TiO2载体结构对钴基催化剂结构和费-托合成反应性能的影响.结果表明:合成的TiO2-B和TiO2-C载体具有高的比表面积和丰富的介孔结构,负载的钴基催化剂上钴物种均以Co3O4形式存在并高度分散在载体上;与TiO2-P相比,TiO2-B负载的催化剂具有更高的催化反应活性和C5+选择性,以及低的CH4选择性.

Preparation of mesoporous TiO2 with high surface area and study on the performance of Fischer-Tropsch synthesis of supported cobalt catalyst

Two kinds of mesoporous TiO2 carriers with high surface area, TiO2-B and TiO2-C, were prepared by hydrothermal method with tetrabutyl titanate and titanium isopropanol as titanium source and CTAB and Brij56 as surfactant. Commercial P25(TiO2-P) was used as reference support. Cobalt catalysts were prepared by means of incipient wetness impregnation method. The catalysts were characterized by N2 adsorption-desorption, in-situ X-ray diffraction(in-situ XRD) and hydrogen temperature programmed reduction(H2-TPR) technique. The results show that TiO2-B and TiO2-C have high surface area and stable mesoporous structure. Cobalt existed as Co3O4 crystalline phase on the support in all calcined catalysts. TiO2-B supported cobalt catalyst had higher catalytic activity, lower CH4 product selectivity and higher C5+ product selectivity in comparison to TiO2-P.