New insights on the mechanism of vapour phase hydrolysis of sodium borohydride in a fed-batch reactor


Akkus M. S. , MURATHAN H. B. , ÖZGÜR D. , ÖZKAN G., ÖZKAN G.

INTERNATIONAL JOURNAL OF HYDROGEN ENERGY, cilt.43, ss.10734-10740, 2018 (SCI İndekslerine Giren Dergi) identifier identifier

  • Cilt numarası: 43 Konu: 23
  • Basım Tarihi: 2018
  • Doi Numarası: 10.1016/j.ijhydene.2018.01.177
  • Dergi Adı: INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
  • Sayfa Sayıları: ss.10734-10740

Özet

This study aims to produce H-2 from sodium borohydride (NaBH4) and to initiate its hydrolysis at elevated temperature in the absence of a catalyst. Experimental results indicated that the hydrogen generation yield increased up to %99 at 150 degrees C in the NaBH4 concentration of %5 wt in the acidic medium. It can be concluded that experimental characterization of the by-products is quite important since they affected the reaction mechanism or pathway. When the experiments are carried out under aqueous condition, the primary by-product is sodium metaborate while it is boric acid under acidic condition. It is postulated that by-product boric acid decreased the mass transfer limitation due to its higher solubility that prevents the formation of shell and thus increases the contact area between NaBH4 and vapor. A series of fed-batch reactions were performed to confirm the hypothesis, and the conversions of NaBH4 reached 99% under the acidic condition. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.