Insights into the Diffusion Behaviors of Water over Hydrophilic/Hydrophobic Catalysts During the Conversion of Syngas to High‐Quality Gasoline

Abstract

Although considerable efforts towards directly converting syngas to liquid fuels through Fischer–Tropsch synthesis have been made, developing catalysts with low CO2 selectivity for the synthesis of high‐quality gasoline remains a big challenge. Herein, we designed a bifunctional catalyst composed of hydrophobic FeNa@Si‐c and HZSM‐5 zeolite, which exhibited a low CO2 selectivity of 14.3 % at 49.8 % CO conversion, with a high selectivity of 62.5 % for gasoline in total products. Molecular dynamic simulations and model experiments revealed that the diffusion of water molecules through hydrophilic catalyst was bidirectional, while the diffusion through hydrophobic catalyst was unidirectional, which were crucial to tune the water‐gas shift reaction and control CO2 formation. This work provides a new fundamental understanding about the function of hydrophobic modification of catalysts in syngas conversion.

Role of H2O in Catalytic Conversion of C1 Molecules

“…Furthermore, operando two-dimensional MRI spectroscopy indicates that H 2 O in the reactor accumulates on the surface of the pores of the catalyst, forming a water-rich local environment that influences the catalytic performance. Recently, Xu et al 96 reported the enhanced selectivity toward liquid hydrocarbons in FTS on a bifunctional catalyst composed of a hydrophobic Fe-based catalyst and HZSM-5 zeolite. Molecular dynamic simulations coupled with experiments indicate different diffusion behaviors of H 2 O on the catalyst surfaces with different hydrophilicity/hydrophobicity.…”

Exploring Greener Pathways and Catalytic Systems for Ethylene Carbonate Production

“…82 (c) Probing catalyst hydrophobicity: investigating the diffusion behavior of water away from a hydrophobic catalyst's surface. 93 (d) Mass transfer enhancement with continuous CO 2 flow and water removal: continuous water stripping using an atmospheric CO 2 flow for polycarbonate synthesis. 77 low cost, have a high capacity for CO 2 loading and low capacity for water, be stable at temperatures of around 180 °C, and be safe for industrial use.…”

“…74 There may be further scope to improve the system performance by increasing the hydrophobicity of the surface, to promote diffusion of water away from the catalyst. 93 Research is needed to develop advanced catalyst preparation techniques, supported by fundamental mechanistic investigations, for a highly efficient EC synthesis. The use of 3D-printed catalysts appears to have great potential in this application from retrievability considerations and prevention of water adsorption, 82 although further research is needed to investigate suitable catalyst configurations for high mass transfer and energy efficiency.…”

“…The research to date has identified ceria as a highly prospective catalytic material, with the potential for performance optimization through the control of nanocrystalline morphology and surface chemistry . There may be further scope to improve the system performance by increasing the hydrophobicity of the surface, to promote diffusion of water away from the catalyst . Research is needed to develop advanced catalyst preparation techniques, supported by fundamental mechanistic investigations, for a highly efficient EC synthesis.…”

“…(b) Exploration of additive manufacturing techniques: utilizing a 3D-printed catalyst made from graphene-supported CeZrLa mixed oxides for the CO 2 to propylene carbonate reaction 82. (c) Probing catalyst hydrophobicity: investigating the diffusion behavior of water away from a hydrophobic catalyst's surface 93. (d) Mass transfer enhancement with continuous CO 2 flow and water removal: continuous water stripping using an atmospheric CO 2 flow for polycarbonate synthesis 77.…”