Enhancing selectivity of aromatics in direct conversion of syngas over K/FeMn and HZSM-5 bifunctional catalysts

Abstract

Mixed Fischer-Tropsch synthesis (FTS) catalysts and HZSM-5 (HZ5) have received attention as bifunctional catalysts that directly convert syngas into value-added aromatic monomers. However, both low selectivity of aromatics and severe deactivation remain challenges. Here we report a simple method for obtaining selective aromatics from syngas by tuning the distribution of hydrocarbon (HC) intermediates on K/FeMn. We prepared K/FeMn catalysts with a varying Mn/(Fe+Mn) wt% to demonstrate the effect of the HC distribution as intermediates of aromatization on HZ5. The C6-C10 distribution was increased by addition of up to 60 wt% of Mn promoter due to the improved dispersion of Fe7C3 and alkyl insertion of MnO. At 340 °C under 20 bar, 97.2% CO conversion and 39.8% aromatics selectivity were achieved by using a physically mixed catalyst of K/FeMn with Mn/(Fe+Mn) 60 wt% and HZ5 with an optimization of the FTS-derived C6-C10 olefin yield as efficient intermediates in Syngas to Aromatics (STA). © 2022 Elsevier B.V.