Double regulation of Mg95Ni5 hydride in suppressing ammonia and promoting hydrogen evolution for Mg(BH4)2•2NH3

The study on inhibiting the release of ammonia from Mg(BH4)(2)center dot 2NH(3) has attracted the attention of many researchers. In this paper, a facile method was used to introduce HCS (hydriding combustion synthesis) processed Mg95Ni5 into the Mg(BH4)(2)center dot 2NH(3) system, which successfully suppressed the release of ammonia completely. The composite shows the best hydrogen desorption kinetics when Mg(BH4)(2)center dot 2NH(3) and Mg95Ni5 hydride were mixed in a mass ratio of 2:1. The initial dehydrogenation temperature of the composite is as low as 75 degrees C, which is 70 degrees C lower than that of Mg(BH4)(2)center dot 2NH(3). In the thermal desorption test, when the temperature rises to 500 degrees C, the amount of hydrogen released is 11.66 wt%, reaching 98.4% of the total amount of hydrogen released. The excellent performance of inhibiting ammonia and releasing hydrogen is attributed to the dual regulation effects of MgH2 and nickel. Magnesium hydride can effectively inhibit ammonia release, and the high dispersibility of nickel improves the kinetic performance of MgH2 in the system. This study further confirms the ammonia suppression effect of MgH2 on Mg(BH4)(2)center dot 2NH(3) and provides ideas for improving the kinetic performance of the composite system. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

The study introduces a facile method of using Mg95Ni5 to suppress the release of ammonia completely in the Mg(BH4)(2)center dot 2NH(3) system. The composite exhibits the best hydrogen desorption kinetics when Mg(BH4)(2)center dot 2NH(3) and Mg95Ni5 hydride are combined in a mass ratio of 2:1.