Enhanced hydrogen sorption in a Li-Mg-N-H system by the synergistic role of Li4(NH2)3BH4and ZrFe2.
The present investigation describes the synergistic role of Li4(BH4)(NH2)3and ZrFe2in the hydrogen storage behaviour of a Li-Mg-N-H hydride system. The onset desorption temperature of ZrFe2-catalysed Mg(NH2)2-LiH-Li4(BH4)(NH2)3is ∼122 °C, which is 83 °C, 63 °C, and 28 °C lower than that of thermally treated 2LiNH2-1MgH2, 2LiNH2-1MgH2-4 wt%ZrFe2, and 2LiNH2-1MgH2-0.1LiBH4composites, respectively. Native Mg(NH2)2-LiH-Li4(BH4)(NH2)3absorbed only 2.78 wt% of H2within 30 min. On the other hand, the ZrFe2-catalysed Mg(NH2)2-LiH-Li4(BH4)(NH2)3sample absorbed 3.70 wt% of hydrogen within 30 min and 5 wt% of H2in 6 h at 180 °C and 7 MPa H2pressure. Mg(NH2)2-LiH-Li4(BH4)(NH2)3catalyzed with ZrFe2shows negligible degradation of the storage capacity even after repeated cycles of de/rehydrogenation. The effect of ZrFe2and Li4(BH4)(NH2)3on a Mg(NH2)2/LiH composite has been described and discussed with the help of structural (X-ray diffraction), microstructural (electron microscopy), and vibrational modes of molecules through FTIR studies. The present results suggest that an optimum catalysis may originate from the synergistic action of an in situ formed quaternary hydride (Li4(BH4)(NH2)3) and an intermetallic-like ZrFe2, which acts as a pulverizer cum catalyst.
Hydrogen Energy Centre, Department of Physics, Banaras Hindu University, Varanasi-221005, India. heponsphy@gmail.com.
Vivek
V
Shukla
Hydrogen Energy Centre, Department of Physics, Banaras Hindu University, Varanasi-221005, India. heponsphy@gmail.com.
Ashish
A
Bhatnagar
Hydrogen Energy Centre, Department of Physics, Banaras Hindu University, Varanasi-221005, India. heponsphy@gmail.com.
Pawan K
PK
Soni
Hydrogen Energy Centre, Department of Physics, Banaras Hindu University, Varanasi-221005, India. heponsphy@gmail.com.
Alok K
AK
Vishwakarma
Hydrogen Energy Centre, Department of Physics, Banaras Hindu University, Varanasi-221005, India. heponsphy@gmail.com.
M A
MA
Shaz
Hydrogen Energy Centre, Department of Physics, Banaras Hindu University, Varanasi-221005, India. heponsphy@gmail.com.
T P
TP
Yadav
Hydrogen Energy Centre, Department of Physics, Banaras Hindu University, Varanasi-221005, India. heponsphy@gmail.com.
O N
http://orcid.org/0000-0003-3634-5759
ON
Srivastava