Chain-like ZSM-5 zeolite coupled with Cu-Fe3O4 for CO2 hydrogenation to light aromatics

Abstract

The capture and utilization of carbon dioxide (CO2) have attracted much attention in recent years; in particular, the direct hydrogenation of CO2 to light aromatics has been considered as a potential route to produce high value-added chemicals. However, it is still a big challenge to adjust the aromatic distribution and achieve a high selectivity to the targeted products. In this work, a bifunctional catalyst that combines the Cu-modified Fe3O4 and the chain-like ZSM-5 zeolite is used for the hydrogenation of CO2 to light aromatics. The catalyst components were characterized by XRD, SEM, TEM, ICP-AES, Py-IR and N2 adsorption-desorption; the effect of acid density and length-to-diameter ratio (b-axis/a-axis) of zeolite moiety on the selectivity and distribution of aromatic products was then investigated. The results indicate that the chain-like ZSM-5 zeolite moiety with high acid density and appropriate length-to-diameter ratio can promote the C–C coupling for CO2 hydrogenation and inhibit the formation of CH4, which can improve the selectivity to aromatics and the space time yield (STY) of toluene.