Highly effective conversion of CO2 into light olefins abundant in ethene

Abstract

•Cr2O3(SG)/H-SAPO-34 shows a C2=−C4= selectivity of 95.7% in CO2 hydrogenation •Ethene accounts for more than 74% of light olefins with an E/P ratio reaching 3.1 •Ethanol is formed through the reaction of H3CO∗ with CO2 and H∗ on Cr2O3(SG) •Ethanol is converted into ethene on SAPO-34 and leads to high C2=−C4= selectivity Conversion of CO2 into light olefins is an effective strategy for sustainable utilization of fossil energy and biomass. However, highly selective production of specific olefin, such as ethene, from CO2 hydrogenation is a challenge. Thus, a new catalyst consisting of Cr2O3(SG) oxide and H-SAPO-34 zeolite is fabricated. It shows C2=−C4= selectivity in hydrocarbons as high as 95.7% at 370°C and 0.5 MPa. More interestingly, around 74% of light olefins are ethene, with an ethene/propene (E/P) ratio of 3.1, which is three times that of previously reported results. This catalytic performance is well maintained for at least 600 h. In situ spectroscopy, DFT calculation, and MD simulation results reveal that ethanol, in addition to methanol, is produced on Cr2O3(SG) through successive hydrogenations of CH3COO∗ intermediate, which is generated through the reaction of H3CO∗ with CO2 and H∗. The ethanol is quickly converted into ethene on H-SAPO-34 and is responsible for the primary light olefin distribution. Conversion of CO2 into light olefins is an effective strategy for sustainable utilization of fossil energy and biomass. However, highly selective production of specific olefin, such as ethene, from CO2 hydrogenation is a challenge. Thus, a new catalyst consisting of Cr2O3(SG) oxide and H-SAPO-34 zeolite is fabricated. It shows C2=−C4= selectivity in hydrocarbons as high as 95.7% at 370°C and 0.5 MPa. More interestingly, around 74% of light olefins are ethene, with an ethene/propene (E/P) ratio of 3.1, which is three times that of previously reported results. This catalytic performance is well maintained for at least 600 h. In situ spectroscopy, DFT calculation, and MD simulation results reveal that ethanol, in addition to methanol, is produced on Cr2O3(SG) through successive hydrogenations of CH3COO∗ intermediate, which is generated through the reaction of H3CO∗ with CO2 and H∗. The ethanol is quickly converted into ethene on H-SAPO-34 and is responsible for the primary light olefin distribution.