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

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.