Boosting liquid hydrocarbons selectivity from CO2 hydrogenation by facilely tailoring surface acid properties of zeolite via a modified Fischer-Tropsch synthesis

Abstract

Catalytic conversion of greenhouse CO2 into valuable chemicals or fuels is highly attractive in terms of sustainable development. The chemical inertness of CO2 molecules and high kinetic barriers for C–C propagation hinder its efficient utilization. Here we report a bifunctional catalyst composed of K-Fe/C and zeolite that efficiently produced liquid fuels via simply tuning the microenvironment properties of ZSM-5 zeolite. The catalysts are characterized by Brunauer-Emmett-Teller (BET), transmission electron microscopy (TEM), X-ray diffractometer (XRD), temperature programmed desorption (NH3-TPD), X-ray photoelectron spectroscopy (XPS). K-Fe/C catalyst is mainly responsible for the formation of olefins, while ZSM-5 catalyst is mainly responsible for olefin secondary reaction, such as aromatization, isomerization, and cracking reaction. Surface acid properties of ZSM-5 can be well regulated through different ion-exchange strategies (NH4+, K+, Na+, Mg2+, Cu2+, Cs2+, La3+, Ce2+, Mn2+), in which the strong surface acid properties of ZSM-5 are eliminated with the utilization of K+-ion exchange strategy and then it presents a high C5+ selectivity by suppressing the light saturated hydrocarbons formation. This work provides new insights or facile catalyst treatment for the efficient production of liquid fuels from CO2 hydrogenation via tuning surface microenvironment properties of ZSM-5 zeolite.