Synthesis and hydrogen storage properties of lithium borohydride urea complex

Interaction of [BHx] and [NHx] species gives rise of molecular hydrogen and the set-up of B-N bond. Metal amides and ammonia are the commonly used [NHx] sources. Herein, urea (CO(NH2)(2)), an organic carbonyl diamide, was applied to react with LiBH4. A new type of complex hydrides LiBH4 center dot CO(NH2)(2), was synthesized by ball milling LiBH4 and CO(NH2)(2) in a molar ratio of 1:1 in this work. Structural analyses show that this newly developed complex has a monoclinic structure (space group C12/c1) with unit-cell parameters of a = 14.629(2) angstrom, b = 5.8701(11) angstrom, c = 13.662(3) angstrom, beta = 115.135(7)degrees, and V = 1062.1(3) angstrom(3), in which Li+ coordinates with two [BH(4)1(-) groups and two O atoms of two CO(NH2)(2) molecules. The dehydrogenation properties of LiBH4 center dot CO(NH2)(2) were subsequently measured, and ca. 8.13 wt% of H-2 can be released exothermically at temperatures below 250 degrees C. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.