a: calculated from N2adsorption-desorption data b: calculated from Hg
intrusion data
c: d(Co) = 0.75
d(Co3O4) d: D (%) =
96/d(Co)
All catalysts presented similar reduction behavior according to the
reduction profiles of the catalysts studied by H2-TPR,
as seen in Figure 1S(c) (see Supporting Information). The reduction
peaks at 200°C-300°C, 250°C-500°C, 550°C-900°C were usually contributed
to the reduction of Co3O4 to CoO, CoO to
metallic Co31,32,37 and the reduction of amorphous
Co/silica phase, individually, Co/S50 and Co/S150 had relatively larger
area of the second reduction peak which was mainly caused by the larger
crystallites size of these two catalysts. Besides, the quite weak
reduction peaks (at 250°C-500°C) of all catalysts indicated a good
reducibility and a weak interaction between active phase and supports.
4.2 Reaction performance assessment over hierarchical catalyst
After 24 h of reaction with the steady state achieved, the performances
of the prepared FTS catalysts are collected as in Table 3S (see
Supporting Information) and Figure 3. The large catalyst pellets (10-20
mesh) of FTS, commonly recognized to bear severe internal diffusion
limitations, were employed to investigate the mass transfer enhancement
with the meso-macropore structure.