The Adsorption And Structure Of Nitrogen-Doped Plant-Based Activated Carbon

Hemp stems and melamine were used to prepare the high-surface-area N-doped activated carbons by different doping methods. Microcosmic figures, textural, chemical structure characterizations and hydrogen adsorption properties of samples were studied through SEM, nitrogen adsorption, FT-IR,αs plot and DFT method. Influence of nitrogen and various texture parameters on hydrogen storage was proposed.According to the results, All N-doped samples were microporous materials with nitrogen adsorption isotherms of typeⅠ, including high surface areas(1674.82-2961.72m·g-1)and total pore volumes(0.9837-1.7532cm3·g-1). The pore sizes were dominated by 0.6-0.7nm and 1.0-1.5nm range of micropores with a small amount of mesopores (2.0-5.0nm). The carbon materials will produce more ultramicropores and less mesopores after treated in the autoclave.The surface of N-doped activated carbon may contain some chemical structure such as O-H,-CH3,-CH2-,C=C,C-O. In the form of -C-N, nitrogen was introduced to carbon materials. All N-doped samples obtained high hydrogen uptakes (2.0wt%-3.1wt%) at 77K and 1bar, And the maximum hydrogen uptake measured for the sample prepared by melamine and the carbonized hemp stem precursor reached 3.1wt%(in gravimetric), and this process is the most efficient way to prepared hydrogen-storage activated carbons.