Hydrogen generation using sodium borohydride solution and metal catalyst coated on metal oxide

Sodium borohydride (<f>NaBH4</f>) reacted slowly with water to liberate <f>4 mol</f> of hydrogen/mol of the compound at room temperature. Hydrogen generation was accelerated by applying metal–metal oxide catalysts such as <f>Pt</f>–<f>TiO2</f>, Pt–CoO and <f>Pt</f>–<f>LiCoO2</f>. As the metal crystallites size decreased and the amount increased, the hydrogen generation rate increased. It was indicated that the hydrogen generation rates using Pt and <f>LiCoO2</f> were high compared with those using other metal and metal oxide, respectively. It seemed that a key finding was that use of the supercritical <f>CO2</f> method produced a superior catalyst.Borohydride ion was stabilized in alkaline solution containing at least 5% by weight of NaOH. Alkaline stabilized solution of <f>NaBH4</f> can be applied as a hydrogen source. We found that <f>Pt</f>–<f>LiCoO2</f> worked as an excellent catalyst for releasing hydrogen from the stabilized <f>NaBH4</f> solution. [Copyright &y& Elsevier]