Selective Hydrogenation of CO2 to Aromatics over Composite Catalyst Comprising NaZnFe and Polyethylene Glycol-Modified HZSM-5 with Intra- and Intercrystalline Mesoporous Structure

Abstract

CO2 hydrogenation to aromatics can significantly reduce emissions of the CO2 and provide a complementary route for the production of aromatics. Herein, we report a composite catalyst comprising Na- and Zn-promoted Fe catalyst (NaZnFe) and highly stable hierarchical nanocrystalline HZSM-5 modified by PEG for CO2 hydrogenation to aromatics. The subtle synergy between Na and Zn in NaZnFe promoted the formation and exposure of active iron species and the conversion of CO2 and intermediates. In addition, the PEG modification of HZSM-5 cannot only fabricate intracrystalline mesopores to improve mesoporosity but also provide appropriate acidity, endowing high aromatic selectivity and catalytic stability. Significantly, the high-efficiency diffusion on hierarchical HZSM-5 intensifies the synergistic effect in the catalytic system. The composite catalyst could suppress the total selectivity of CO and CH4 to less than 15% with an aromatic selectivity of up to 63.68% among all hydrocarbons and BTX selectivity in aromatics of up to 56.35% at a CO2 conversion of 42.08%.