Preparation of Single-Phase Iron Nitrides and Investigation of Their Fischer-Tropsch Synthesis Performance

Abstract

Single-phase of ζ-Fe2N, ϵ-Fe3N, γ′-Fe4N and χ-Fe5C2 were obtained by pretreating reduced α-Fe at proper temperature and atmosphere. The morphology, bulk structure and surface properties are different because of the interstitial atoms N. The bulk structure of iron nitrides was investigated by X-ray diffraction spectra and the surface properties were investigated by field emission scanning electron microscopy, N2-adsorption isotherms, X-ray photoelectron spectroscopy and CO-temperature programmed desorption. Iron nitrides have similar texture properties. It is found that the binding energy values of Fe atoms which bond with N are smaller in ζ-Fe2N. Iron nitride which with low iron content has stronger interaction with CO and has higher specific activity and C5+ selectivity. And the low molecular weight product selectivity of iron nitrides is higher than χ-Fe5C2.