Improved dehydrogenation performance of NaAlH4 using NiFe2O4 nanoparticles

Abstract The dehydrogenation properties of commercial NaAlH 4 ball milled with a NiFe 2 O 4 nanoparticle catalyst have rarely been studied. In this work, temperature programmed desorption analysis indicates that the onset temperature of three dehydrogenation steps of NaAlH 4  + 3 mol% NiFe 2 O 4 is 72, 132 and 82 °C lower than those of as-milled NaAlH 4 , respectively. The dehydrogenation capacity of NaAlH 4 could be significantly improved by adding NiFe 2 O 4 . Furthermore, NaAlH 4  + 3 mol% NiFe 2 O 4 displays good cycle stability at 150 °C and only a slight capacity loss after five cycles. The apparent activation energies of NaAlH 4  + 3 mol% NiFe 2 O 4 for the three dehydrogenation steps are 54.3, 73.1 and 113.1 kJ mol −1 , respectively, as determined by differential scanning calorimetry and Kissinger analysis. From the analysis of X-ray diffraction, the new phases after dehydrogenation are NaFeO 2 and Al 3 Ni. The reaction between NiFe 2 O 4 and NaAlH 4 during desorption is revealed.