Effects of supports on catalytic performances of Fe-based catalysts for CO2 hydrogenation to light olefins
The selection of suitable support is crucial for the rational design of novel and efficient Fe-based catalysts for CO2 hydrogenation to light olefins(ethylene,propylene and butene).Supports were synthesized by hydrothermal method,and impregnated with K and Fe to prepare a series of Fe-based catalysts(K-Fe/ZrO2,K-Fe/ZnO,K-Fe/TiO2 and K-Fe/Al2O3).The effects of these supports on the catalytic performance of CO2 hydrogenation were investigated.The catalysts were characterized by XRD,N2 absorption/desorption,Raman,CO-TPD,CO2-TPD,in suit Raman and water droplet contact angle tests,and the induction effects of supports on the generation of Fe active species were studied.The results show that under reaction conditions of temperature of 320℃,pressure of 2.0 MPa,feed gas V(CO2):V(H2):V(Ar)=1:3:3 and gas hourly space velocity of 10000 mL/(g·h),K-Fe/ZrO2 exhibites superior selectivity of light olefins(42.4%)and CO2 conversion rate(36.2%).Compared to other catalysts,K-Fe/ZrO2 has a suitable adsorption capacity for CO and CO2,which is beneficial for CO2 activation and carbon deposition.It also inhibits the secondary hydrogenation of olefins while obtaining more FexCy active species.Additionally,K-Fe/ZrO2 exhibites strong hydrophobicity due to carbon deposition during the reaction process,further reducing the degree of water oxidation of FexCy and improving the selectivity of light olefins.
CO2 hydrogenationlight olefinssupportdynamic evolutionFe-based catalysts
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