Fe-Co-K/ZrO2 Catalytic Performance of CO2 Hydrogenation to Light Olefins

In recent years, with the consumption of fossil resources and the large amount of CO2 emissions, the energy crisis and the greenhouse question become deeply serious. The direct synthesis of olefins by CO2 hydrogenation with iron-based catalysts is one of the best ways to achieve CO2 reduction. In this study, zirconia (ZrO2)-supported iron-cobalt catalyst (Fe-Co/ZrO2) and ZrO2-supported iron-cobalt-potassium catalyst (Fe-Co-K/ZrO2) were prepared by impregnation method, which were used for CO2 hydrogenation to light olefins (C-2(=)-C-4(=)), and the effect of K on the catalytic activity were investigated emphatically. At the condition of 300 degrees C and 1.5 MPa, the activity test show that addition of K increases the CO2 conversion from 40.8% to 44.8%, improves the selectivity of light olefins from 0.23% to 68.5%, and raises the stability of catalytic performance. The characterization results show that introduction of K improves electron cloud density of the iron species, enhances adsorption strength of the Fe to CO2, promotes the formation of iron carbide, and facilitates direct dissociation of CO2 after adsorption on Fe species, thus boosts the performance of CO2 hydrogenation to light olefins.

Automated summary

This study prepared different catalysts for CO2 hydrogenation to light olefins, showing that the addition of K can enhance CO2 conversion, improve the selectivity of light olefins, and increase the stability of catalytic performance. The characterization results indicate that the introduction of K improves the catalytic activity by enhancing electron cloud density of the iron species and promoting the formation of iron carbide.