Thesis Review. Synthesis of fibrous activated carbons and monoliths for hydrogen storage

fibers (ACFs), activated carbon nanofibers (ACNFs), as well as activated carbon monoliths from different precursors. Regarding the synthesis of activated carbon fibers (ACFs), it turned out that the carbonization temperature of the original carbon fiber had a high impact on the porosity development, a detail which previously had not been taken into account. Other activation parameters (activation time and temperature, nitrogen flow, mixing method, etc.) were also studied. By combining different carbonization temperatures of the precursors on the one hand and different amounts and types of activating agents on the other hand, samples with a wide range of porosity development were prepared. Thus, ACF samples with BET surface areas over 3000 m 2 g -1 and very selective porosity distributions were synthesized. In particular, some samples revealed very narrow distributions of micropores and V DR (CO 2 ) values of around 0.8 cm 3 g -1 which are particularly interesting for the storage of hydrogen at room temperature. In addition, two scale-up activations were successfully carried out, in order to synthesize large amounts of ACFs with suitable properties for hydrogen storage applications. The amount of sample produced was approximately an order of magnitude higher compared to the laboratory scale activations. The degree of activation was slightly higher for the scaleup activations. Therefore, higher porosity and lower yields than on laboratory scale were obtained. In both scale-ups, the produced ACFs reached BET surface areas of around 2300 m 2 g -1 , high V DR (CO 2 ) up to 0.8 cm 3 g -1 and packing densities around 0.6 g cm -3 . Activated carbon nanofibers (ACNFs) were produced from a type of carbon nanofiber (CNF) of amorphous nature. Surprisingly, CO 2 was more effective when compared with other activating agents (H 2 O, alkali hydroxides). When CO 2 was used as activating agent, a suitable porosity for storing H 2 was developed and better activation yields were obtained. BET surface areas up to 2000 m 2 g -1 , V DR (CO 2 ) of 0.6 cm 3 g -1 and packing densities near 0.5 g cm -3 were reached. Monoliths were produced from activated carbons, ACFs, and ACNFs, reaching high densities up to 0.7 g cm -3 . These were higher than the bulk densities and the densities of the original compressed fibers