The Effect Of Ca Doping On The CO2 Hydrogenation Performance Of CaxZn10‐xFe20 Catalysts (x=0, 0.5, 1 and1.5)

Abstract

In this paper, CaxZn10-xFe20 catalysts were prepared by the co-precipitation method and applied to CO 2 hydrogenation. The experimental results show that the CO 2 conversion of the catalyst Ca1Zn9Fe20 at a Ca doping amount of 1 mmol can reach 57.91 %, which is 13.5 % more than the CO 2 conversion of the catalyst Zn10Fe20. Moreover, the catalyst Ca1Zn9Fe20 has the lowest selectivity for both CO and CH 4, with 7.40 % and 6.99 %, respectively. The catalysts were characterized by XRD, N 2 adsorption-desorption, CO 2 -TPD, H 2 -TPR, and XPS. The results demonstrate that the doping of Ca increases the basic sites on the catalyst surface and thus allows the catalyst to adsorb more CO 2 to promote the reaction. Besides, the Ca doping amount of 1 mmol can suppress the formation of graphitic carbon on the catalyst surface and prevent the excess graphitic carbon from covering the active site Fe 5 C 2 .

Development of Mg-Modified Fe-Based Catalysts for Low-Concentration CO2 Hydrogenation to Olefins

“…On one hand, they can promote the dispersal, reduction, and carburization of Fe species and improve the stability of the FeC x active phase. On the other hand, the electron transfer from promoters to Fe species weakens the C–O bonds and inhibits the H 2 dissociation, thus favoring the formation of olefins and long-chain hydrocarbons. − Moreover, it was also found that CO 2 on MgO surfaces can be activated into carbonate substances, and Mg x -H complexes have stronger electron-donating effects, which can promote the formation of *HCOO, a critical intermediate species in the CO 2 hydrogenation reaction . Thus, it is critical to regulate the adsorption of reactants and the electronic structure of active sites to realize the effective coupling of RWGS and FTS reactions.…”