Effect of several metal chlorides on the thermal decomposition behaviour of α-Mg(BH 4) 2

• Published in: International journal of hydrogen energy 2011-09, Vol.36 (19), p.12313-12318
• Main Authors: Bardají, Elisa Gil, Hanada, Nobuko, Zabara, Oleg, Fichtner, Maximilian
• Format: Article
• Language: English
• Subjects: Additive; Alternative fuels. Production and utilization; Applied sciences; Energy; Exact sciences and technology; Fuels; HP-DSC; Hydrogen; Hydrogen storage; In-situ XRD; Magnesium borohydride; TG-MS
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2011.07.008

Mechanochemical alloying of Mg(BH 4) 2 with small amounts of metal chlorides (PdCl 2, TiCl 3, VCl 3, MoCl 3, RuCl 3, CeCl 3 and NbCl 5) results in the formation of transition metal doped nanocomposites with different hydrogen desorption properties. The thermal decomposition properties of ball-milled as well as doped α-Mg(BH 4) 2 have been studied. An amorphization reaction of Mg(BH 4) 2 is induced by ball milling, nevertheless a partial recrystallization of the alpha phase takes place after heating up to 150 °C. The effect of ball milling Mg(BH 4) 2 with each additive has been investigated in detail by using differential scanning calorimetry, thermogravimetric analysis and X-ray diffraction. The onset temperature of Mg(BH 4) 2 is lowered by more than 100 °C through the addition of Nb- or Ti chloride. Moreover, a mixed Ti-Nb-nanocomposite was also synthesized and investigated. The onset temperature of hydrogen evolution during decomposition of the mixed Ti-Nb-nanocomposite is considerably lowered by up to 125 °C. ► Transition metal chlorides as dopants of magnesium borohydride. ► Thermal decomposition behaviour of several nanocomposites investigated. ► Onset temperature of Ti–Ni nanocomposite lowered up to 125 °C. ► Improvement of the hydrogen desorption properties of magnesium borohydride.