Enhanced Fischer-Tropsch synthesis performance on fe + ZSM5 bifunctional catalysts

Abstract

Fischer-Tropsch synthesis (FTS) is viewed as an effective method for producing clean fuels. Catalysts with high activity and selectivity, especially the latter, are the key to improving the catalytic performance. Herein, we report the preparation of an excellent bifunctional Fe + ZSM5 catalyst by employing novel hierarchical porous Fe₂O₃ cage particles as FTS sites and porous ZSM5 as catalytic cracking sites. The selectivity for gasoline fuels (C₅-C₁₁) selectivity over the Fe + ZSM5(33) catalyst is as high as 65.1 wt%, which is greater than that of traditional outstanding than the traditionally zeolite-supported and physically mixed bifunctional catalysts. The enhanced catalytic performance can be attributed to the weak acid content governing the catalytic cracking. ZSM5 zeolite with a suitable weak acid content and desorption temperature can facilitate the cracking of C₁₂₊ hydrocarbons, thereby facilitating the C₅-C₁₁ selectivity and inhibiting the deactivation of active sites resulting from the aggregation of C₁₂₊ hydrocarbons. Fe + ZSM5(27) with an suitable weak acid content provides a higher CO conversion of 93.6% combined with an excellent C₅-C₁₁ selectivity of 62.7 wt%. This finding provides a promising strategy for designing bifunctional catalysts with controllable product distribution.