Sodium borohydride composite gel with high energy density as a hydrogen source for portable power

Abstract

Due to increasing energy demand and concern over the urban environment, there is a need to develop a hydrogen based economy or turning to hydrogen as a source of fuel. The rapid development of fuel cells can be considered a solution as it can generate power with higher efficiency and zero emissions. Hence, a safe and efficient hydrogen supply is essential for portable power. Currently, there exists several options of hydrogen supply and storage such as stored as compressed gas, liquid hydrogen, steam reforming and in metal hydrides. Hydrogen can be produced via the hydrolysis reaction of sodium borohydride, NaBH4 and water. This performance of the reaction can be improved with the addition of the cobalt boron catalyst. In this project, NaBH4 and the catalyst is impregnated into the super absorption polymer, SAP beads. The absorbency of the SAP beads of different diameters is tested using water and NaOH + NaBH4 solution. Different concentrations of NaBH4 in the NaOH + NaBH4 solution are used in the absorbency test too. The hydrogen produced from the hydrolysis reaction of the impregnated beads and water are investigated. It had been found that as the diameter of the SAP beads increases, the hydrogen generation rate decreases. The maximum hydrogen accumulated volume also decreases as the diameter increases. Lastly, the NaBH4 usage efficiency is the highest when the SAP diameter is the smallest.