Preparation of Fe-Mn catalyst by hydrothermal method and its catalytic activity for the synthesis of light olefins from CO hydrogenation

A series of potassium modified Fe-Mn catalysts were prepared by hydrothermal method and applied to the catalytic synthesis of light olefins from CO hydrogenation.The catalyst samples were characterized by SEM,TEM,XRD,H2-TPR and FT-IR techniques.Results showed that the prepared sample particles were spherical with 50~70 nm size and the carbonyl and hydroxy groups were observed on their surfaces.The bulk composition was mainly Fe3O4 before the reaction.Fe5C2 and MnCO3 were formed after the reaction.The prepared samples showed high activity and olefin selectivity under the given reaction conditions.Using the sample S3(Fe∶Mn∶C6∶K=3∶1∶5∶0.10),the CO conversion and the olefin productivity reached 95.02% and 62.86 g/m3(H2+CO),respectively.Compared with the catalyst prepared with co-precipitation method,the S 3catalyst had lower CH4 selectivity(13.88%) and CO2 selectivity(13.98%).