Direct hydrogenation of carbon dioxide (CO2) to value-added chemicals is a promising strategy to relive the greenhouse effect and replace the diminishing fossil fuels, but the huge CO2 inertness and C–C coupling barrier usually bring about numerous difficulties and count against catalytic performance. Here, a highly active and more economical composite catalyst composed of Cu-promoted Fe2O3 (nCu-Fe2O3) and HZSM-5 was developed for the selective conversion of CO2 to aromatics with 56.61% selectivity at a single pass. An extremely low CO selectivity of 3.51 at 57.30% CO2 conversion outperforming the previously reported conversion was achieved because of the beneficial synergism between Cu and Fe and the distinctive CO reduction prior to reaction which is favorable to the formation of oxygen vacancies for CO2 adsorption and iron carbide for Fischer–Tropsch synthesis (FTS). Additionally, through integrating HZSM-5 synthesized by the phase-transfer method (HZSM-5-pt) with nCu-Fe2O3, the distribution of benzene, toluene, and xylene in aromatics can be noteworthily increased to 54.18% and aromatics selectivity can be increased to 61.94%, without depression of catalyst activity. More significantly, a “H recycling” mechanism was found between oxide and zeolite, which plays a crucial role in “the disposal of H” within dehydrogenative aromatization, facilitating the formation of aromatics. In summary, nCu-Fe2O3/HZSM-5 demonstrates a prospective industrial application in aromatics production from CO2.

A composite catalyst of a metal oxide and a zeolite has been widely adopted for the direct conversion of syngas to aromatics (STAs). However, its stability along with higher conversion and selectivity remains a bigger challenge to overcome. Herein, we present an efficient STA catalyst composed of a Na-modified Fe−Mn oxide and an HZSM-5 zeolite; however, a gradual decline was observed in the aromatization activity of the zeolite, which was significantly ascribed to the influence of elemental migration from the Fe-based catalyst to the zeolite. Further investigation revealed that the migrated metal oxides could block pore channels; meanwhile, abundant Na diminished Lewis acid sites by donating electrons to the zeolite during the reaction, which adversely affected the catalytic performance. Therefore, on synthesizing a well-designed catalyst in optimized promoter contents and integrating it with high-acidity nano-HZSM-5 in proper proximity, a higher CO conversion greater than 95% and an overall aromatic selectivity exceeding 53% were achieved with extended stability of 120 h. This work reveals a particular dimension for the microscopic interaction between the metal oxide and the zeolite in the composite catalyst, providing a promising perception of catalyst design for the synthesis of aromatics from syngas.

Tailoring the crystal lattice and multiple phase interfaces via the feasible accommodation of Cu–Co into the host (Fe) structure, expedited the surface oxygen vacancies that modulated the reduction/chemisorption behavior of active Fe species.