The paper presents results on the three-dimensional (3D) functionalization of graphite-originated flakes to graphene by carbonization of specific precursors in the presence of a hard template. In situ precipitated Na2CO3 nanocrystals or CaCO3 nano-powder were used as a hard template. Graphene flakes were obtained by a wet chemistry exfoliation of commercial graphite. The flakes were premixed with a non-specific binder and the hard template and then carbonized at temperatures of 700 to 800 °C under the flow of nitrogen. The addition of a template allowed to increase the surface area up 287 m2/g for the Na2CO3 template and 333 m2/g in the case of CaCO3, while the surface area of 25 m2/g was noted for the raw graphite. Several instrumental methods were applied for the characterization of the obtained 3D-graphene materials: combustion elemental analysis, SEM, HRTEM, XPS, Raman spectroscopy and low-temperature adsorption of nitrogen. The effect of the addition of a template and the carbonization temperature on the surface area of the 3D structured graphene was demonstrated. The wet-chemistry method led to an efficient deglomeration of graphene flakes to double (DLG) and few (FLG) layered graphene. The proposed method is inexpensive.