CO2 hydrogenation to light olefins over Cu-CeO2/SAPO-34 catalysts: Product distribution and optimization

Abstract The direct conversion of carbon dioxide into hydrocarbons is a very desirable but difficult approach for achieving lower value-added olefins with minimal CO selectivity. In this effort, we report the direct conversion of CO2 into light olefins on a Cu/CeO2 hybrid catalyst mixed with SAPO-34 zeolite. The samples are characterized by N2 sorption, XRD, TEM, SEM, NH3-TPD and H2 -TPR. The results showed that the acidity of modified zeolite had decreased. The response surface methodology has been used to optimize the operating parameters (temperature and space velocity (SV)) of process. A high olefin selectivity of 70.4% has been obtained on CuCe/SAPO-34 at H2/CO2 =3, 10 h, 382.46 °C, 17.33 L/g.h and 20 bar. The optimum operating conditions for multiple responses have also been achieved. The optimal values are T = 396.26 °C and SV = 5.80 L/g.h. Under these conditions, the predicted olefin and CO selectivity and CO2 conversion are 61.83%, 57.11% and 13.15%, respectively. Multiple optimization outputs are outstanding for obtaining the suitable operating conditions.