Intermediate Product Regulation in Tandem Solid Catalysts with Multimodal Porosity for High-Yield Synthetic Fuel Production.

Abstract

Tandem catalysis is an attractive strategy to intensify chemical technologies. However, simultaneous control over the individual and concerted catalyst performances poses a challenge. We demonstrate that enhanced pore transport within a Co/Al2 O3 Fischer-Tropsch (FT) catalyst with hierarchical porosity enables its tandem integration with a Pt/ZSM-5 zeolitic hydrotreating catalyst in a spatially distant fashion that allows for catalyst-specific temperature adjustment. Nevertheless, this system resembles the case of close active-site proximity by mitigating secondary reactions of primary FT α-olefin products. This approach enables the combination of in situ dewaxing with a minimum production of gaseous hydrocarbons (18 wt %) and an up to twofold higher (50 wt %) selectivity to middle distillates compared to tandem pairs based on benchmark mesoporous FT catalysts. An overall 80 % selectivity to liquid hydrocarbons from syngas is attained in one step, attesting to the potential of this strategy for increasing the carbon efficiency in intensified gas-to-liquid technologies.