Synthesis and thermal decomposition behaviors of magnesium borohydride ammoniates with controllable composition as hydrogen storage materials

Yanjing Yang; Yongfeng Liu; You Li; Mingxia Gao; Hongge Pan

doi:10.1002/asia.201200970

Synthesis and thermal decomposition behaviors of magnesium borohydride ammoniates with controllable composition as hydrogen storage materials

Chem Asian J. 2013 Feb;8(2):476-81. doi: 10.1002/asia.201200970. Epub 2012 Nov 28.

Authors

Yanjing Yang¹, Yongfeng Liu, You Li, Mingxia Gao, Hongge Pan

Affiliation

¹ State Key Laboratory of Silicon Materials & Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China.

PMID: 23192895
DOI: 10.1002/asia.201200970

Abstract

An ammonia-redistribution strategy for synthesizing metal borohydride ammoniates with controllable coordination number of NH(3) was proposed, and a series of magnesium borohydride ammoniates were easily synthesized by a mechanochemical reaction between Mg(BH(4))(2) and its hexaammoniate. A strong dependence of the dehydrogenation temperature and purity of the released hydrogen upon heating on the coordination number of NH(3) was elaborated for Mg(BH(4))(2)·xNH(3) owing to the change in the molar ratio of H(δ+) and H(δ-), the charge distribution on H(δ+) and H(δ-), and the strength of the coordinate bond N:→Mg(2+). The monoammoniate of magnesium borohydride (Mg(BH(4))(2)·NH(3)) was obtained for the first time. It can release 6.5% pure hydrogen within 50 minutes at 180 °C.