A novel catalytic route for hydrogenation-dehydrogenation of 2LiH + MgB2via in situ formed core-shell LixTiO2 nanoparticlesElectronic supplementary information (ESI) available. See DOI: 10.1039/c7ta03117c

• Main Authors: Puszkiel, J. A, Castro Riglos, M. V, Ramallo-López, J. M, Mizrahi, M, Karimi, F, Santoru, A, Hoell, A, Gennari, F. C, Larochette, P. Arneodo, Pistidda, C, Klassen, T, Bellosta von Colbe, J. M, Dornheim, M
• Format: Journal Article
• Language: English
• Published: 27.06.2017
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/c7ta03117c

Aiming to improve the hydrogen storage properties of 2LiH + MgB 2 (Li-RHC), the effect of TiO 2 addition to Li-RHC is investigated. The presence of TiO 2 leads to the in situ formation of core-shell Li x TiO 2 nanoparticles during milling and upon heating. These nanoparticles markedly enhance the hydrogen storage properties of Li-RHC. Throughout hydrogenation-dehydrogenation cycling at 400 °C a 1 mol% TiO 2 doped Li-RHC material shows sustainable hydrogen capacity of ∼10 wt% and short hydrogenation and dehydrogenation times of just 25 and 50 minutes, respectively. The in situ formed core-shell Li x TiO 2 nanoparticles confer proper microstructural refinement to the Li-RHC, thus preventing the material's agglomeration upon cycling. An analysis of the kinetic mechanisms shows that the presence of the core-shell Li x TiO 2 nanoparticles accelerates the one-dimensional interface-controlled mechanism during hydrogenation owing to the high Li + mobility through the Li x TiO 2 lattice. Upon dehydrogenation, the in situ formed core-shell Li x TiO 2 nanoparticles do not modify the dehydrogenation thermodynamic properties of the Li-RHC itself. A new approach by the combination of two kinetic models evidences that the activation energy of both MgH 2 decomposition and MgB 2 formation is reduced. These improvements are due to a novel catalytic mechanism via Li + source/sink reversible reactions. Aiming to improve the hydrogen storage properties of 2LiH + MgB 2 (Li-RHC), the effect of the in situ formed and low cost Li x TiO 2 is investigated.