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The Onset of Dehydrogenation in Solid Ammonia Borane: An Ab Initio Metadynamics Study
Author(s) -
Rizzi Valerio,
Polino Daniela,
Sicilia Emilia,
Russo Nino,
Parrinello Michele
Publication year - 2019
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201900134
Subject(s) - ammonia borane , diborane , metadynamics , dehydrogenation , chemistry , ab initio , hydrogen storage , computational chemistry , hydrogen , sodalite , ab initio quantum chemistry methods , chemical physics , molecule , molecular dynamics , catalysis , organic chemistry , zeolite , boron
The discovery of effective hydrogen storage materials is fundamental for the progress of a clean energy economy. Ammonia borane (H 3 BNH 3 , AB) has attracted great interest as a promising candidate but the reaction path that leads from its solid phase to hydrogen release is not yet fully understood. To address the need for insights in the atomistic details of such a complex solid state process, in this work we use ab‐initio molecular dynamics and metadynamics to study the early stages of AB dehydrogenation. We show that the formation of ammonia diborane (H 3 NBH 2 (μ‐H)BH 3 ) leads to the release of NH 4 + , which in turn triggers an autocatalytic H 2 production cycle. Our calculations provide a model for how complex solid state reactions can be theoretically investigated and rely upon the presence of multiple ammonia borane molecules, as substantiated by standard quantum‐mechanical simulations on a cluster.