Hydrogen production from sodium borohydride for fuel cells in presence of electrical field

Abstract

Sodium borohydride (NaBH4) reacts with water to produce 4 mol of hydrogen per mol of compound at room temperature. Under certain conditions, it was found that 6 mol of hydrogen per mol of sodium borohydride was produced in the presence of electrical field created by DC voltages, whereas 4 mol of hydrogen was produced in the presence of catalyst per mole of sodium borohydride. Electrical field created by alternative current with three different waves (sin, square and triangle type) increases the hydrolysis of sodium borohydride. It was found that hydrogen produced from sodium borohydride by applying an electrical field can be effectively used for both increasing the electrolysis of water and hydrolysis of sodium borohydride. The hydrolysis reaction was carried out at temperature of 20, 30, 40 and 60°C in the presence of electrical field created by AC voltages square wave. The experimental data were fitted to the kinetic models of zero-order, first-order and nth-order. The results indicate that the first-order and nth-order model give a reasonable description of the hydrogen generation rate at the temperature higher than 30°C. Reaction rate constant at different temperatures were determined from experimental data, and activation energy was found to be 50.20 and 52.28 kJ mol−1 for first-order and nth-order, respectively. Copyright © 2009 John Wiley & Sons, Ltd.