Study of K/Mn‐MgO Supported Fe Catalysts with Fe(CO)₅ and Fe(NO₃)₃ as Precursors for CO Hydrogenation to Light Alkenes

Abstract

Two K/Mn-MgO supported catalysts were prepared by Fe(CO) 5 and Fe(NO 3 ) 3 as precursor respectively. The obtained Fe-K/Mn-MgO catalysts were tested for CO hydrogenation to light alkenes and characterized by X-ray powder diffraction (XRD), X-ray photoelectron spectra (XPS), H 2 temperature-programmed reduction (H 2 -TPR), H 2 , CO and CO 2 temperature-programmed desorption (H 2 , CO/CO 2 -TPD) and transmission electron microscope (TEM). The results indicated that the catalyst with 10 wt% Fe loading prepared by Fe(CO) 5 as precursor showed better performance in syngas to light alkenes than ones obtained from Fe(NO 3 ) 3 as precursor, where the CO conversion was 62.50% and the selectivity was 55.95% at 350 ℃, 1.5 MPa and 1000 h −1 , respectively.

Developing Multifunctional Fe-Based Catalysts for the Direct Hydrogenation of CO2 in Power Plant Flue Gas to Light Olefins

“…This reminds us that improved CO2 adsorption favors the formation of CO species. In addition, the gaseous CH4 product (3015 cm −1 ) was detected as the reaction continued [39,49]. We speculate that the CO species was the intermediate of CH4 formation, while the formate acted as a spectator in our catalyst [50,51].…”

“…The CO2-TPD results of the KFMM0 and KFMM0.15 catalysts are shown in Figure 8b. There are three CO2 desorption peaks corresponding to weakly adsorbed CO2 (α) below 200°C, moderately strongly adsorbed CO2 (β) at 200~500 °C, and strongly adsorbed CO2 (γ) above 550 °C [39,40]. It was found that the addition of Mg slightly weakened CO2's adsorption strength, leading to the desorption temperature (325 °C) being closer to the reaction temperature (320 °C).…”

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.…”