Highly efficient ZnCeZrOx/SAPO-34 catalyst for the direct conversion of CO2 into light olefins under mild reaction conditions

Abstract

Currently, restricting the formation of CO and paraffin by-products at mild reaction conditions, and avoiding the waste of carbon resources remain challenging for CO2 hydrogenation into light olefins. Herein, we constructed a bifunctional catalyst consisting of Zn0.3Ce0.2Zr1.8O4 solid solution and SAPO-34 zeolite. The catalyst shows excellent performance with a high C2= – C4= selectivity of 90.1% and an O/P ratio of 60.1 at a CO2 conversion of 6.0% at 280 ºC and 0.5 MPa, while the selectivity of CO is only 7.9%. Various characterization and designed experiment results demonstrate that incorporating appropriate amounts of Ce in Zn0.3ZrOx generates more oxygen vacancies that improve CO2 activation to form formate and methoxy intermediates at low temperature and pressure. This promotes the evolution of these intermediates into light olefins over the SAPO-34 zeolite, enhancing the overall capacity of the bifunctional Zn0.3Ce0.2Zr1.8O4/SAPO-34 composited catalyst in CO2 hydrogenation under mild conditions.