Mesoporous H‐ZSM‐5 (mesoH‐ZSM‐5) was used as a carrier for a series of bifunctional Co‐based catalysts for Fischer–Tropsch synthesis with ZrO2 and/or Ru added as promoters. The reducibility of the catalysts was studied in detail by using temperature‐programmed reduction and X‐ray absorption spectroscopy. A comparison of the catalytic performance of Co/mesoH‐ZSM‐5 and Co/SiO2 (a conventional catalyst), after 140 h on stream, reveals that the former is two times more active and three times more selective to the C5–C11 fraction with a large content of unsaturated hydrocarbons, which is next to α‐olefins. The acid‐catalyzed conversion of n‐hexane and 1‐hexene, as model reactions, demonstrates that the improvement in the selectivity toward gasoline range hydrocarbons is due to the acid‐catalyzed reactions of the Fischer–Tropsch α‐olefins over the acidic zeolite. The formation of methane over the zeolite‐supported Co catalysts originates from direct CO hydrogenation and hydrocarbon hydrogenolysis on coordinatively unsaturated Co sites, which are stabilized as a consequence of a strong metal–zeolite interaction. Although the addition of either ZrO2 or Ru increases the catalyst reducibility considerably, it does not affect the product selectivity significantly.

Wax on, wax off: Bifunctional cobalt-based catalysts on zeolite supports are applied for the valorization of biosyngas through Fischer-Tropsch chemistry. By using these catalysts, waxes can be hydrocracked to shorter-chain hydrocarbons, increasing the selectivity towards the C5 -C11 (gasoline) fraction. The zeolite topology and the amount and strength of acid sites are key parameters to maximize the performance of these bifunctional catalysts, steering Fischer-Tropsch product selectivity towards liquid hydrocarbons.

Looking out for gasThe cover picture shows the complexity behind the direct formation of gasoline from syngas mixtures over bifunctional zeolite Fischer-Tropsch catalysts. In their Full Paper on p. 142 ff., S. Sartipi, J. Gascon et al., by combining a thorough catalytic performance evaluation with in-depth characterization techniques, unravel the origins of the high selectivity to gasoline range hydrocarbons and the effect of the zeolitic support on the cobalt active phase.