Selective Production of Aromatics Directly from Carbon Dioxide Hydrogenation

Conversion of carbon dioxide (CO2) to fuels and chemicals with the help of renewable hydrogen (H-2) is a very attractive approach to reduce CO2 emissions and replace dwindling fossil fuels. However, it is still a great challenge to synthesize aromatics directly from CO2 hydrogenation, because CO2 is thermodynamically very stable, and the aromatics are highly unsaturated products with complex structures. Here, we demonstrate that the combination of the sodium-modified spinel oxide ZnFeOx, which alone shows excellent performance for CO2 hydrogenation to olefins, and hierarchical nanocrystalline HZSM-5 aggregates can realize a highly efficient synthesis of aromatics directly from CO2 and H-2. The maximum of aromatics selectivity was up to 75.6% among all hydrocarbons at 41.2% CO2 conversion. Additionally, the selectivity toward CO and CH4 is usually less than 20% over this catalyst system. The suitable amount of the residual sodium, hierarchical pore structure, and appropriate density of Bronsted acid sites endow the composite catalyst with an outstanding aromatics yield and high catalytic stability.