Preparation and study of the optical properties of porous graphite

Optical properties of porous graphite samples prepared by electrochemical etching were investigated. It is found that electrochemical etching modifies their Raman spectra and gives rise to photoluminescence. The evolution of Raman spectra at the initial etching stages is studied in detail. A model is proposed explaining the salient features of the observed Raman spectra. It assumes the appearance of graphite nanoparticles and the formation of $sp^3$ bonds between the graphite planes at the nanocrystal boundaries.