Synthesis of modified fulleren structures and uses in hydrogen storage

In this study, firstly, optimum conditions were determined for the production of defective fullerenes from fullerene at different milling times and milling speeds. Then, these structures were functionalized by hydroxylation and amination reactions; then, lithium-doped fullerene, defective fullerene and functionalized fullerene/defective fullerene samples were synthesized by hydrothermal method with lithium doping. The obtained samples were characterized comprehensively by FTIR, Raman, DTA/TG, SEM/EDX, TEM and BET analysis techniques. Hydrogen storage capacities of the characterized samples were investigated in a wide pressure range at room and cryogenic temperatures. The sample with the highest BET surface area and pore volume among the defective fullerene samples was defined as "K-C60-1h-500rpm". Adsorption-desorption isotherms showed hysteresis and generally showed results compatible with Type I and Type IV isotherms. Hydrogen storage capacity in all samples increased with increasing pressure and decreasing temperature. Experimental data showed compliance with Henry's law at room temperature, while multilayer adsorption isotherm behavior was observed at cryogenic temperature. It was found that functionalization and lithium doping processes had different and distinct effects on hydrogen storage capacities. Furthermore, the experimental data were analyzed by pseudo-first-order, pseudo-second-order and Elovich equations, and the results were in good agreement with the second-order kinetic equation.