Selective Production of Aromatics Directly from Carbon Dioxide Hydrogenation over nNa–Cu–Fe2O3/HZSM-5

Abstract

Na and Cu additives have been widely studied for their promotional efficiency of Fe-based catalysts directly converting CO2 to valuable hydrocarbons. Selective hydrogenation of CO2 toward aromatics, however, is still a huge challenge. Herein, we fabricated a bifunctional catalyst comprising Fe2O3 promoted by Na and Cu and hierarchical nanocrystalline HZSM-5, and then the catalytic performance and reaction conditions of CO2 hydrogenation were investigated by coupling nNa–Cu–Fe2O3 catalysts with HZSM-5. The maximum aromatic selectivity achieved 57.74% (including CO) at 33.26% CO2 conversion, and the proportion of aromatics in liquid products reached up to 94.81%. Moreover, the selectivity of light aromatics achieved 30.36%. The subtle synergy between Na and Cu in Fe2O3 contributed to the activation of iron species and the conversion of intermediates. In addition, the enhanced mesoporous and appropriate acidity over HZSM-5 was attributed to the post-treatment modification which facilitated the high aromatic selectivity and outstanding catalytic stability. Significantly, fast diffusion pulled off the synergistic effect on the tandem reaction owing to the presence of hierarchical HZSM-5.