[en] Graphene sheets formed by the reaction of carbon monoxide (CO) with aluminum sulfide (Al₂S₃) at reaction temperatures ≥ 800 .deg. C were characterized by X-ray diffraction (XRD), Raman spectroscopy, and high-resolution transmission electron microscopy (HRTEM). The graphene sheets, formed as CO was reduced to gaseous carbon by the reaction with Al₂S₃, in the temperature range 800 - 1100 .deg. C, did not exhibit their characteristic XRD peaks because of the small number of graphene layers and/or low crystallinity of graphene sheets. Raman spectra of graphene sheets showed that the intensity ratio of the D band to the G band decreased and the 2D band was shifted to higher frequencies with increasing reaction temperature, indicating that the number of graphene layers increased with increasing reaction temperature