Mössbauer spectroscopy studies of iron-graphite catalysts derived from graphite intercalation compounds

Abstract

Very active catalysts can be prepared from FeCl₃-GIC precursors through a two-step reduction and washing with HCl. Mössbauer spectrometry during the first (H₂) reduction step indicates that Fe⁰ in the form of α-Fe is obtained together with two non-equivalent Fe^II sites. This α-Fe is catalytically inactive and can be readily removed from the system treatment with HCl. The second reduction with potassium vapour transforms the remaining Fe^II into catalytically active Fe⁰ which is strongly resistant to the HCl treatment.