An investigation into carbon structures in iron-loaded charcoal based on the Raman shift and line-shape of the G´-band

Charcoal samples prepared from wood impregnated with Fe 3+ were characterized using Raman spectroscopy to investigate ordered structures consisting of sp 2 -carbon atoms. The iron-loaded charcoal samples were synthesized at relatively low temperatures (600–850 °C). Most of the Raman peak-tops of G´-bands observed in the charcoal were positioned in the narrow range of 2700–2690 cm −1 ; however, the G´-band positions of the charcoal synthesized in a carbonization-temperature (CT) range (650–750 °C) varied widely with measurement points and some of them displayed wavenumber values lower than 2690 cm −1 . The G´-band positions were also affected by holding time at CT. None of the G´-bands observed in the iron-loaded charcoal exhibited positive asymmetrical line-shapes, unlike graphite. We proposed the ordered structures of sp 2 -carbon atoms in the iron-loaded charcoal based on the Raman spectral features of the G´-bands.