Cascade Catalysis for the Selective Synthesis of Multi-Branched Alkanes From Syngas

Co-based composite catalysts with assorted zeolite have been extensively utilized to improve gasoline octane numbers by isomerization enhancement in Fischer-Tropsch synthesis products. Nevertheless, their catalytic potential remains constrained due to insufficient secondary isomerization activity. Herein, we propose a three-stage catalyst system, denoted as (Co/SiO 2 + 0.5Pt/SiO 2 ) + ZSM-5 + Beta, designed to synergistically promote multi-branched alkane formation. Elaborate experimental results confirm the formation of straight-chain hydrocarbons on Co/SiO 2 , while the 0.5Pt/SiO 2 component elevates intermediate olefin concentrations from 11.0% to 12.5%. The subsequent zeolite cascade enables precision isomerization: ZSM-5 (10-membered ring channels) preferentially generates mono-branched alkanes, whereas Beta zeolite (12-membered ring channels) drives secondary branching through advanced isomerization. This catalyst configuration achieves a significant increase in multi-branched alkane selectivity within isomerized products. The demonstrated cascade mechanism establishes a framework for direct syngas-to-branched hydrocarbon conversion, suggesting generalizable principles for cascade catalyst design in selective hydrocarbon upgrading. Graphical