A facile synthesis of SiO₂@Co/mSiO₂ egg-shell nanoreactors for Fischer-Tropsch reaction

Recently, a convenient melt-infiltration method, using a hydrated metal salt with porous support, was developed to prepare various metal/metal-oxide nanocatalysts. Until now, millimeter-scale, bead-shaped, cobalt egg-shell catalysts have been used to enhance the rate of reactant diffusion and catalyst performance. In the present work, new SiO₂@Co/mSiO₂ egg-shell nanoreactors (∼300 nm) were synthesized with controlled Co content of 10 and 20 wt%. This was accomplished using a selective melt-infiltration process with porous silica shells around solid-silica cores. The SiO₂@Co(10 wt%)/mSiO₂ egg-shell catalyst that bears small cobalt nanoparticles of ∼2 nm was successfully employed for the industrially valuable Fischer-Tropsch synthesis reaction, showing the high activity of ∼ 8.0×10^-5 mol_CO ·g^-1 _Co · s^-1.