Enhanced hydrogen release of metal borohydrides M(BH sub(4)) sub(n) (M = Li, Na, Mg, Ca) mixed with reduced graphene oxide

• Published in: International journal of hydrogen energy Vol. 41; no. 26; pp. 11225 - 11231
• Main Authors: Nale, Angeloclaudio, Pendolino, Flavio, Maddalena, Amedeo, Colombo, Paolo
• Format: Journal Article
• Language: English
• Published: 13.07.2016
• Subjects: Borohydrides; Decomposition; Decomposition reactions; Graphene; Graphite; Lithium; Magnesium; Oxides
• ISSN: 0360-3199
• DOI: 10.1016/j.ijhydene.2016.04.191

Mixtures of light metal borohydrides M(BH sub(4)) sub(n), M = Li, Na, Mg, Ca and reduced graphene oxide (rGO) or graphite with molar ratio 70:30 were prepared by high energy ball milling. Samples were investigated with thermal programmed desorption (TPD) volumetric analysis to test their gas release profiles. The presence of rGO led to a lower decomposition temperature for every mixture and to a different gas-release profile compared to pristine borohydrides and mixtures with graphite. The onset of decomposition temperature was reduced by 200 degree C for LiBH sub(4), 360 degree C for NaBH sub(4), 130 degree C for Mg(BH sub(4)) sub(2) and 50 degree C for Ca(BH sub(4)) sub(2). The comparison of XRD profiles of decomposed samples showed a different pattern for each metal cation, confirming an interaction of the decomposition products with rGO sheets and suggesting a different pathway for the decomposition reaction. Reduced graphene oxide was prepared by clean thermal treatment in H sub(2) atmosphere from graphene oxide obtained by modified wet chemical synthesis, and its presence significantly affected the gas release performance.