Diborane Release from LiBH₄/Silica-Gel Mixtures and the Effect of Additives

LiBH 4 that has been ball-milled with different additives and subsequently mixed with mesoporous silica-gel has been investigated using thermal desorption spectroscopy and thermogravimetry. Mixtures of LiBH 4 and mesoporous silica-gel (composition 50:50 wt %) release hydrogen at ∼260 °C. Samples, where LiBH 4 was ball-milled prior to mixing with silica-gel with 5 mol % PdCl 2, NiCl 2, LaCl 3 or TiCl 3, have similar decomposition temperatures. Mass spectrometry data of the emitted gas streams show that almost all hydrogen desorption events are accompanied by the evolution of gaseous diborane, B 2 H 6 . The relative diborane concentration above 350 °C is considerably lowered by LaCl 3 and TiCl 3, whereas the other additives investigated have little influence on the amount of released diborane.