Revision of the NaBO₂-H₂O phase diagram for optimized yield in the H₂ generation through NaBH₄ hydrolysis

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• 作者：Jé ; rô ; me Andrieux ; ^{jerome.andrieux@esrf.fr} ; Laetitia Laversenne¹ ; Olesia Krol ; Rodica Chiriac ; Zeinab Bouajila ; Richard Tenu ; Jean Jacques Counioux ; Christelle Goutaudier
• 关键词：Hydrogen storage ; Hydrolysis ; Sodium borohydride ; Sodium borate ; NaBO2&ndash ; H2O binary phase diagram ; Thermodynamics
• 刊名：International Journal of Hydrogen Energy
• 出版年：2012
• 期刊代码：42_03603199
• 类别：ch
• 出版时间：April, 2012
• 卷：37
• 期：7
• 页码：5798-5810
• 文件大小：1446 K

摘要

The binary phase diagram NaBO₂-H₂O at ambient pressure, which defines the different phase equilibria that could be formed between borates, end-products of NaBH₄ hydrolysis, has been reviewed. Five different solid borates phases have been identified: NaBO₂路4H₂O (Na[B(OH)₄]路2H₂O), NaBO₂路2H₂O (Na[B(OH)₄]), NaBO₂路2/3H₂O (Na₃[B₃O₄(OH)₄]), NaBO₂路1/3H₂O (Na₃[B₃O₅(OH)₂]) and NaBO₂ (Na₃[B₃O₆]), and their thermal stabilities have been studied. The boundaries of the different Liquid聽+聽Solid equilibria for the temperature range from 鈭?0 to 80聽掳C have been determined, confirming literature data at low temperature (20-50聽掳C). Moreover the following eutectic transformation, Liq.聽鈫捖營ce聽+聽NaBO₂路4H₂O, occurring at 鈭?聽掳C, has been determined by DSC. The Liquid-Vapour domain has been studied by ebullioscopy. The invariant transformation Liq.聽鈫?/strong>聽Vap. + NaBO₂路2/3H₂O has been estimated at 131.6聽掳C. This knowledge is paramount in the field of hydrogen storage through NaBH₄ hydrolysis, in which borate compounds were obtained as hydrolysis reaction products. As a consequence, the authors propose a comparison with previous NaBO₂-H₂O binary phase diagrams and its consequence related to hydrogen storage through NaBH₄ hydrolysis.