Development of a green catalytic route to light olefins by Fischer-Tropsch synthesis with renewable hydrogen: Investigation of boron doped activated carbon supported iron catalyst

Abstract

Hydrogen economy will open the door to a low carbon future and Fischer–Tropsch Synthesis (FTS) is one of the sustainable and carbon neutral catalytic route to a variety of products such as light olefins, kerosene, gasoline etc. when CO and H2 come from catalytic reduction of air captured CO2 and water electrolysis using the surplus renewable electricity, respectively. The aim of this study is to discover the new catalysts towards the sustainable C2–C4 olefins. Activated carbon (AC) supported zinc titanates w/o boron doping have been prepared and investigated for olefins via FTS. AC was deliberately chosen due to its surface structure more prone to modification since boron (B) is known to increase the interaction between surface metal atoms and defects. The B-doped AC supported iron catalyst showed comparable catalytic stability as the original AC supported one. However, an only increase in light olefin selectivity was observed with B-doping treated at 800 C. On the other side, a higher CH4 and paraffin but lower olefin and C5+ selectivity was obtained at the lower thermal treatments. B-doping appeared to improve the catalytic stability but not to bring the expected catalytic activity and selectivity. The strong interaction between the surface metal sites and boron is believed to cause the restricted formation of active sites that leads less CO conversions.