Characterisation of carbon nanotube foam for improved gas storage capability

Advanced fuel cells require efficient hydrogen storage tanks. This study presents preliminary results on a novel compound based on an alumina substrate coated with carbon nanotube foam (CNF) that is expected to improve substantially the hydrogen storage capability. A catalytic chemical vapour deposition (CCVD) technique was applied for obtaining the desired structure. It involved the organometallic compound ferrocene (a simultaneous source of iron and carbon), H₂ as reducing gas, and Ar as dragging gas. The CNF-alumina system formed was characterised by means of scanning and transmission electron microscopy (SEM, TEM, resp.). Applying the BET method with N₂ as carrier gas, it was found that the novel compound exhibits a high specific surface area, due to the porous morphology, and a high thermal stability. These aspects are very promising for the application intended. The sponge-like structure of the CNF may store hydrogen (or other gases) due to physical adsorption in much larger quantities as compared to conventional storage tanks.