Metal borohydride formation from aluminium boride and metal hydrides

TY - JOUR

T1 - Metal borohydride formation from aluminium boride and metal hydrides

AU - Møller, Kasper Trans

AU - Fogh, Alexander

AU - Paskevicius, Mark

AU - Skibsted, Jørgen

AU - Jensen, Torben René

PY - 2016

Y1 - 2016

N2 - Metal borides are often decomposition products from metal borohydrides and thus play a role in the reverse reaction where hydrogen is absorbed. In this work, aluminium boride, AlB 2, has been investigated as a boron source for the formation of borohydrides under hydrogen pressures of p(H 2) = 100 or 600 bar at elevated temperatures (350 or 400 °C). The systems AlB 2-MH x (M = Li, Na, Mg, Ca) have been investigated, producing LiBH 4, NaBH 4 and Ca(BH 4) 2, whereas the formation of Mg(BH 4) 2 was not observed at T = 400 °C and p(H 2) = 600 bar. The formation of the metal borohydrides is confirmed by powder X-ray diffraction and infrared spectroscopy and the fraction of boron in AlB 2 and M(BH 4) x is determined quantitatively by 11B MAS NMR. Hydrogenation for 12 h at T = 350-400 °C and p(H 2) = 600 bar leads to the formation of substantial amounts of LiBH 4 (38.6 mol%), NaBH 4 (83.0 mol%) and Ca(BH 4) 2 (43.6 mol%).

AB - Metal borides are often decomposition products from metal borohydrides and thus play a role in the reverse reaction where hydrogen is absorbed. In this work, aluminium boride, AlB 2, has been investigated as a boron source for the formation of borohydrides under hydrogen pressures of p(H 2) = 100 or 600 bar at elevated temperatures (350 or 400 °C). The systems AlB 2-MH x (M = Li, Na, Mg, Ca) have been investigated, producing LiBH 4, NaBH 4 and Ca(BH 4) 2, whereas the formation of Mg(BH 4) 2 was not observed at T = 400 °C and p(H 2) = 600 bar. The formation of the metal borohydrides is confirmed by powder X-ray diffraction and infrared spectroscopy and the fraction of boron in AlB 2 and M(BH 4) x is determined quantitatively by 11B MAS NMR. Hydrogenation for 12 h at T = 350-400 °C and p(H 2) = 600 bar leads to the formation of substantial amounts of LiBH 4 (38.6 mol%), NaBH 4 (83.0 mol%) and Ca(BH 4) 2 (43.6 mol%).

U2 - 10.1039/C6CP05391B

DO - 10.1039/C6CP05391B

M3 - Journal article

SN - 1463-9076

VL - 18

SP - 27545

EP - 27553

JO - Physical Chemistry Chemical Physics

JF - Physical Chemistry Chemical Physics

IS - 39

ER -