Nano-Structured Carbon Matrixes Obtained from Chitin and Chitosan by a Novel Method

A series of porous carbon matrixes was prepared by phosphoric (V) acid activation of unconventional precursors chitin and chitosan: impregnation with H3PO4 at concentrations ranging from 1.34 to 5.53 mole dm(-3), followed by carbonization at 600 degrees C. The obtained carbons demonstrated well-developed porosity that declined steadily in the micropore and mesosopore ranges, depending on both the kind of the precursor and the concentration of activator. The surface area and pore volume of the carbons prepared from chitin increased upon the rising impregnation ratio. The surface area and total pore volume reached their maximum values (1257 m2g(-1) and 1.007 cm3g(-1), respectively) for the acid concentration of 3.40 mole dm(-3). The chars obtained from chitosan showed the values of the BET surface area ranging from 970 to 1484 m2g(-1). Chemical analysis indicated that the activation with phosphoric acid led to the chars of exceptionally high concentration of nitrogenated functionalities and a typical amount of oxygenated surface groups.