Sulfurized metal borohydrides

Abstract

The reactions between metal borohydrides and elemental sulfur are investigated in situ during thermal treatment and are found to be highly exothermic (up to 700 J g⁻¹). These reactions are exceptionally rapid, occurring below 200 °C, also resulting in the sudden release of substantial quantities of hydrogen gas. For NaBH₄ this hydrogen release is pure, with no detectable levels of H₂S or B₂H₆. The reaction results in the formation of an array of metal–boron–sulfur compounds. These MBH₄–S compounds are interesting for possible uses in high energy applications (fuels or explosives), hydrogen generation, and metal–boron–sulfur precursors.