Investigations on hydrogen storage behavior of CNT doped NaAlH4

In this paper, we have carried out investigations on admixing carbon nanotubes (CNT) to increase the desorption rate of hydrogen in NaAlH4. So far only transition metal Ti has been attempted as the suitable dopant for making NaAlH4 (purified version) a viable hydrogen storage material by increasing the hydrogen desorption rate. Out of the various materials corresponding to NaAlH4-x mol% CNT (x = 2, 4, 6, 8 and 12), we have found that the material with x = 8 mol% is the optimum material. It shows highest desorption rate leading to 3.3 wt.% of H2 at ∼160 °C within 2 h for the first dissociation reaction. The CNT admixed NaAlH4 has also been found to exhibit good rehydrogenation characteristics (reversibility on hydrogenation up to ∼4.2 wt.%). A feasible mechanism for the improvement of hydrogen desorption characteristics has been put forward.