Mossbauer spectroscopy involved in the study of the catalytic growth of carbon nanotubes

Single-walled and thin multiwalled carbon nanotubes are prepared by a catalytic-chemical-vapor-deposition method involving the simultaneous formation of Fe or Co nanometric particles from oxide solid solutions based on Al2O3, MgAl2O4 or MgO. This paper is an overview of the authors' work on the characterization by Mossbauer spectroscopy used in complement to electron microscopy and specific-surface-area measurements. It is notably attempted to correlate the nature of the different iron phases in the carbon nanotube-metal-oxide powders with the formation mechanisms of the nanotubes. Massive composites and hydrogen storage are proposed as possible applications.