Enhancement of hydrogen storage properties of NaAlH4 catalyzed by CuFe2O4

Abstract

This study describes the hydrogen storage performance of NaAlH4 with the addition of CuFe2O4 additive. The results were compared with undoped NaAlH4. For the first and second steps of dehydrogenation, the CuFe2O4-doped NaAlH4 liberated hydrogen at 150 °C and 220 °C, whereas as-milled NaAlH4 released hydrogen at 190 °C and 290 °C, respectively. The desorption kinetic analysis unveiled that the doped system liberated around 1.5 and 4.4 wt% hydrogen within 120 min at 150 and 200 °C, respectively. Meanwhile, the undoped NaAlH4 only desorbed 0.5 and 3.6 wt% hydrogen, respectively, under identical conditions. The activation energy for the doped system at the first step of dehydrogenation was decreased from 114.7 to 92.5 kJ/mol, while reduced from 125.2 to 98.1 kJ/mol at the second stage. The synergistic impact between the in-situ formed Cu2O and Fe during the heating process indicated that these active species are superior in boosting the hydrogen storage performance of NaAlH4.