TUNING Mg HYDRIDING KINETICS WITH NANOCARBONS

Efrat Ruse 1,2 Matat Buzaglo 1 Svetlana Pevzner 2 Ilan Pri Bar 1 Vladimir M. Skripnyuk 3 Eugen Rabkin 3 Oren Regev 1
1Department of Chemical Engineering, Ben-Gurion University of the Negev, Beer-Sheva, Israel
2Department of Chemistry, Nuclear Research Center Negev, Beer-Sheva, Israel
3Department of Materials Science & Engineering, Technion-Israel Institute of Technology, Haifa, Israel

Hydrogen storage is one of the main technological barriers impeding the realization of future hydrogen economy. Among various options for hydrogen storage, metal hydrides (e.g., magnesium hydride) represent one of the most efficient and safe media [1]. Nevertheless, the high hydrogen capacity of magnesium (7.7 wt%) is offset by its sluggish (de)hydriding kinetics below 300oC [2]. The conventional remedy for the less than optimal (de)hydriding kinetics is high-concentration loading with heavy and expensive transition metal catalysts, which limits the overall hydrogen capacity of the Mg [3]. Mg-nanocarbon composites demonstrate fast reversible hydriding kinetics. The kinetics is strongly correlated with the structure of the added nanocarbon allotrope [4]. We conducted a systematic exploration of the reversible hydriding kinetics of Mg upon addition of nanocarbons with different dimensionalities, namely, 1D carbon nanotubes, 2D graphene nanoplatelets and 3D activated carbon [5]. Our findings showed that the Mg (de)hydriding rate could be tuned by the dimensionality and defect density of the nanocarbon. The resulting kinetic enhancement was explained in terms of the hydrogen spillover mechanism. The use of nanocarbons offers an alternative to the utilization of high concentrations of expensive transition-metal catalysts for hydrogen storage.

References

  1. Sakintuna, B., et al., International Journal of Hydrogen Energy, 2007. 32: p. 1121-1140.
  2. Huot, J., et al., Journal of Alloys and Compounds, 1999. 293–295(0): p. 495-500.
  3. Liang, G., et al., Journal of Alloys and Compounds, 1999. 292(1–2): p. 247-252.
  4. Ruse, E., et al., International Journal of Hydrogen Energy, 2016. 41(4): p. 2814-2819.
  5. Ruse, E., et al., Journal of Alloys and Compounds, 2017. 725: p. 616-622.








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