Direct conversion of carbon dioxide into liquid fuels and chemicals by coupling green hydrogen at high temperature

Abstract

The chemical conversion of CO2 into hydrocarbon fuels and chemicals using green hydrogen not only utilizes abundant CO2 as a carbon feedstock but also enables the storage of hydrogen. Herein, we investigate the direct hydrogenation of CO2 to gasoline and olefins over a series of bifunctional iron-zeolite tandem catalysts operated at high temperatures (> 300 ℃). This process may efficiently utilize CO2 discharged from industrial combustion and green H2 produced by solid oxide electrolytic cells (SOEC). The optimized FeMnK+H-ZSM-5 catalyst offers a 70% selectivity of C5−C11 range hydrocarbons together with a 17% selectivity of C2−C4 lower olefins at 320 °C. The CO2 conversion levels and the aromatics contents could be greatly enhanced as the temperature increases from 320 ℃ to 400 ℃. The hydrocarbon distribution is mainly determined by the micropore size of the zeolites. The dynamic evolution of bifunctional catalysts and its impact on bifunctional catalysis was systematically investigated.