MgH2–ZrFe2Hx nanocomposites for improved hydrogen storage characteristics of MgH2. (21st September 2015)

• Record Type: Journal Article
• Authors: Shahi, Rohit R.; Bhatanagar, Ashish; Pandey, Sunita K.; Shukla, Vivek; Yadav, T.P.; Shaz, M.A.; Srivastava, O.N.
• Is Part Of: International journal of hydrogen energy. Volume 40:Number 35(2015)
• Page Start: 11506
• Page End: 11513
• Publication Date: 2015-09-21
• Subjects: Hydrogen storage -- Nanocomposites -- MgH2 -- ZrFe2 -- Intermetallic alloys; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2015.03.162
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: The unfavorable de/re-hydrogenation aspects of high storage capacity material, Mg can be overcome by synthesis of composites with known intermetallic hydrogen storage alloys. In this work, a new additive, ZrFe2 Hx intermetallic hydride, is used to synthesize MgH2 –ZrFe2 Hx nanocomposite by reactive mechanical milling technique. Also this report describes the comparison of hydrogen sorption behavior of MgH2 –ZrFe2 and MgH2 –ZrFe2 Hx nanocomposites. It is found that the composite containing ZrFe2 and ZrFe2 Hx leads to decrease in desorption temperature from 410 °C (for MgH2 ) to 350 and 290 °C respectively. The activation energy for rehydrogenation of composite is found to be ∼61 kJ/mol. This is lowered by 30 kJ/mol compared to the pristine milled MgH2 (92 kJ/mol). Thus, the results show significant improvement of hydrogenation behavior with the addition of ZrFe2 Hx . Reasons for better catalytic activity achieved by using ZrFe2 Hx have been put forwarded. Based on the present studies it can be suggest that the use of hydride version instead of the parent intermetallic phase for synthesizing the composite with MgH2 has a distinct advantage in improving the hydrogenation behavior of MgH2 . Graphical abstract: Highlights: A new additive, ZrFe2 Hx is used to synthesize nanocomposite. Reasons for better catalytic activity by using ZrFe2 Hx put forward. The hydride version of additive has a distinct advantage for MgH2 . ZrFe2 Hx promotes the dissociation of H2 to H atoms.