Energy Sources Part A-recovery Utilization and Environmental Effects, Vol.34, No.12, 1104-1113, 2012
The Processing of NaBH4 from Na2B4O7 by Mechano-chemical Synthesis and Its Catalytic Dehydrogenation
Sodium borohydride (NaBH4) is a specialty reducing agent used in fuel cell systems. Feasible NaBH4 production techniques are required to reduce the costs of NaBH4, making its usage attractive. At present, anhydrous borax (Na2B4O7) is a promising reactant in NaBH4 synthesis. However, further improvements to optimize the yield of the NaBH4 production process operating with MgH2 and Na2B4O7 in ball milling are necessary. In order to obtain optimum reaction conditions, experiments were performed under inert atmosphere. First, we attempted to compensate Na insufficiency with the addition of Na, NaH, and Na2CO3. Next, the reaction period and stoichiometric ratio of our experiments were studied with Na2B4O7 and MgH2 . Reaction times were varied from 200 to 600 min, and regulated the excess MgH2 addition at 0, 10, 30, 50, and 70%. The synthesized products were characterized by FT-IR and XRD analysis and checked our results using iodimetry and dehydrogenation tests. We were able to achieve yield levels of approximately 84% of NaBH4 in certain purification processes with ethylene diamin after 400 min of reaction time and at excess MgH2 levels of 10% or more.