Surface-Controlled Conversion of Ammonia Borane from Boron Nitride

Nakagawa, Tessui; Uesato, Hiroki; Burrell, Anthony K.; Ichikawa, Takayuki; Miyaoka, Hiroki; Davis, Benjamin L.; Kojima, Yoshitsugu

doi:10.3390/en13215569

DOE OSTI · 1787286

Surface-Controlled Conversion of Ammonia Borane from Boron Nitride

Nakagawa, Tessui·Uesato, Hiroki·Burrell, Anthony K.·Ichikawa, Takayuki·Miyaoka, Hiroki·Davis, Benjamin L.·Kojima, Yoshitsugu

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Abstract

“One-pot regeneration”, which is simple regneneration method of ammonia borane (AB) using hydrazine and liquid ammonia, enables conversion of AB from hexagonal boron nitride (h-BN) after milling hydrogenation. Solution 11 B-NMR revealed the presence of AB after NH 3 /N 2 H 4 treatment of milled h-BN (BNH x ) although the yield of AB was less than 5%. The conversion mechanism was clarified as B-H bonds on the h-BN surface created by ball-milling under hydrogen pressure have an ability to form AB, which was confirmed by Thermogravimetry-Residual Gas Analysis (TG-RGA) and Infrared (IR) analysis. The reaction routes are also the same as regeneration route of polyborazylene because intermediates of AB such as (B(NH 2 ) 3 and hydrazine borane were found by solution 11 B-NMR after soaking BNH x in liquid NH 3 and hydrazine, respectively. Because of the fact that all reactions proceed on the h-BN surface and no reaction proceeds when neat h-BN is treated, breaking of B 3 N 3 ring structure and then creation of B-H bond is the key issue to increase conversion yield of AB.

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37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY Ammonia borane Boron nitride Energy sciences Hydrogen storage Hydrogenation Inorganic and physical chemistry Material science Milling Nuclear magnetic resonance

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Nakagawa, Tessui, Uesato, Hiroki, Burrell, Anthony K., Ichikawa, Takayuki, Miyaoka, Hiroki, Davis, Benjamin L., Kojima, Yoshitsugu. 2020-10-23. Surface-Controlled Conversion of Ammonia Borane from Boron Nitride. https://doi.org/10.3390/en13215569

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