Porous graphitic materials obtained from carbonization of organic xerogels doped with transition metal salts

Abstract

Porous carbons with a well developed graphitic phase were obtained via the pyrolysis of FeCl₃-, NiCl₂-, and CoCl₂-doped organic xerogels. Doping was realized through salt solubilization in a water/methanol solution of resorcinol and furfural. Carbon xerogels with tailored particles, porous morphology and various degrees of graphitization were obtained depending of the water/methanol ratio and the salt content and type in the starting solution of substrates. When obtained via pyrolysis, carbon xerogels retain the overall open-celled structure exhibiting depleted microporosity and a well-developed mesoporic region that expands into macropores. The removal of metal leads to carbon xerogels with specific surface areas between 170 and 585 m²/g and pore volume up to 0·76 cm³/g. The possibility of enhancing the porosity of xerogels via templating with colloidal silica was also investigated. It was assumed that from the three investigated salts, FeCl₃ makes the best choice for graphitization catalyst precursor to obtain uniformly graphitized mesoporous carbon xerogels. The obtained carbon samples were characterized by means of SEM, TEM, X-ray diffraction, Raman spectroscopy, N₂ physisorption and thermogravimetric analysis.