Effects of Mn-K synergistic action on iron-based catalyst for CO hydrogenation to light olefins

The catalyst samples with different Fe, Mn and K proportions were prepared by the typical method.The catalyst were characterized by X-ray diffraction(XRD), N₂-adsorption, Raman, scanning electron microscope (SEM) and their performance for CO hydrogenation to light olefins was investigated. The results showed that the incorporation of Mn with appropriate contents can improve the dispersion of the active phase and suppress the carbon chain growth. The interaction of Fe-Mn can not effectively increase olefin/paraffin ratio. Active iron species precursor(α-Fe₂O₃) are more advantageous to olefin formation reaction. Mn oxides are restrained by the addition of K, giving rise to more crystal defects of FeMn compound. As a result, a higher yield of light olefins is acquired for Fe-Mn-K than Fe-Mn and Fe-K catalytic system.