Transformation of Metallic Ti to TiH2 Phase in the Ti/MgH2 Composite and Its Influence on the Hydrogen Storage Behavior of MgH2. Issue 11 (21st April 2020)

• Record Type: Journal Article
• Authors: Pukazhselvan, D.; Sandhya, Karakkadparambil Sankaran; Ramasamy, Devaraj; Shaula, Aliaksandr; Fagg, Duncan Paul
• Is Part Of: Chemphyschem. Volume 21:Issue 11(2020)
• Page Start: 1195
• Page End: 1201
• Publication Date: 2020-04-21
• Subjects: Additives -- catalytic mechanism -- hydrogen storage -- reaction kinetics -- surface reaction; Chemistry, Physical and theoretical -- Periodicals; 541.05
• DOI: 10.1002/cphc.202000031
• Languages: English
• ISSNs: 1439-4235

Abstract

Abstract: The current work explores the in‐situ formation of TiH2 additive in a Ti/MgH2 nanocomposite system. Mild mechanical milling leaves Ti chemically unchanged, while formation of stable TiH2–x occurs upon strong mechanical milling. TiH2–x further transforms to TiH2 upon recycling the powder (dehydrogenation and subsequent hydrogenation) and lowers the activation energy of MgH2 to 89.4 kJ (mol H2 ) −1 [ Ea of as‐received MgH2 is 153 kJ (mol H2 ) −1 ]. This work also reiterates that metallic Ti additive mixed MgH2 requires strong mechanical milling for better H2 ab/de‐sorption performance. The current observations support the view that lattice strain may be an important factor in the catalysis of additives incorporated MgH2 hydrogen storage systems. Abstract : Adding up : Ti is an interesting additive for MgH2 . Ti additive remains chemically variant if the milling is mild. Ti transforms to TiH2–x upon strong milling conditions and its further transformation occurs (TiH2–x to TiH2 ) during the thermal treatment (hydrogenation/dehydrogenation). Hydrogenated Ti seems to be marginally a better additive than Ti but for either case one should ensure that better dispersion of additive (Ti/TiH2–x /TiH2 ) is achieved.