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

Abstract Single‐phase of ζ‐Fe 2 N, ϵ‐Fe 3 N, γ ′‐ Fe 4 N and χ‐Fe 5 C 2 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, N 2 ‐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‐Fe 2 N. Iron nitride which with low iron content has stronger interaction with CO and has higher specific activity and C 5+ selectivity. And the low molecular weight product selectivity of iron nitrides is higher than χ‐Fe 5 C 2 .