Converting CO₂ from a detrimental greenhouse gas into value-added liquid fuels not only contributes to mitigating CO₂ emissions, but also reduces dependence on petrochemicals. However, since CO₂ is a fully oxidized, thermodynamically stable and chemically inert molecule, the activation of CO₂ and its hydrogenation to hydrocarbons or other alcohols are challenging tasks. Most research to date, not surprisingly, is focusing on selective hydrogenation of CO₂ to short-chain products, while few studies on long-chain hydrocarbons, such as gasoline-range (C₅–C₁₁) hydrocarbons. The key to this process is to search for a high efficient catalyst.

CO₂ Hydrogenation to Gasoline-range Hydrocarbons Over Na–Fe₃O₄/Zeolite Multifunctional Catalyst (Image by WEI Jian)

The research team led by Dr. SUN Jian and Prof. GE Qingjie in Dalian Institute of Chemical Physics has succeeded in preparing a high efficient, stable, and multifunctional Na–Fe₃O₄/HZSM-5 catalyst for the direct production of gasoline from CO₂ hydrogenation. This catalyst exhibited 78% selectivity to C₅–C₁₁ as well as low CH₄ and CO selectivity under industrial relevant conditions. And gasoline fraction are mainly isoparaffins and aromatics thus favouring the octane number. Moreover, the multifunctional catalyst exhibited a remarkable stability for 1,000 h on stream, which definitely has the potential to be a promising industrial catalyst for CO₂ utilization to liquid fuels.

In-depth characterizations indicate that this catalyst enables RWGS over Fe₃O₄ sites, olefin synthesis over Fe₅C₂ sites and oligomerization/aromatization/isomerization over zeolite acid sites. The concerted action of the active sites calls for precise control of their structures and proximity. This study paves a new path for the synthesis of liquid fuels by utilizing CO₂ and H₂. Furthermore, it provides an important approach for dealing with the intermittency of renewable sources (sun, wind and so on) by storing energy in liquid fuels.

This work was recently published on Nature Communications (DOI: 10.1038/ncomms15174). This work was financially supported by the National Natural Science Foundation of China, and the Hundred-Talent Program of DICP, Chinese Academy of Sciences.