Cobalt-supported carbon and alumina co-pillared montmorillonite for Fischer–Tropsch synthesis

Abstract

The natural Na-type montmorillonite (Na-MMT) was co-pillared by aluminium polycation and cetyltrimethylammonium bromide (CTAB), and then carbonized in an argon atmosphere to obtain carbon and alumina modified MMT (C-Al-MMT). 20wt.% cobalt was loaded on C-Al-MMT via the impregnation method by using Co(NO3)2·6H2O as a precursor. The materials were characterized by XRD, H2-TPR, H2-TPD, NH3-TPD, O2 titration, TEM, and N2 adsorption–desorption at low temperature. From the composition of different C-Al-MMT, a competitive exchange between CTAB and aluminium polycation during the co-pillaring process was clearly found, leading to a significant change of the textural properties of C-Al-MMT with increasing the content of carbon. Moreover, the introduction of carbon clearly decreased interactions between cobalt and the support, leading to an increased extent of reduction of cobalt. As a result, an active Co/C-Al-MMT catalyst for FT synthesis was obtained by optimizing the content of carbon.