Studying the Effect of Electrode Material and Magnetic Field on Hydrogen Production Efficiency

Abstract

Water electrolysis is one of the most common methods to produce hydrogen gas with high purity, but its application is limited due to its low energy efficiency. It has been proved that an external magnetic field can reduce energy consumption and increase hydrogen production efficiency in water electrolysis. In this study, electrodes with different magnetism were subjected to a perpendicular magnetic field for use in hydrogen production by water electrolysis. Gas bubbles that evolve from the surface of a horizontal electrode detach faster than the bubbles from a vertical electrode. The locomotion of the bubbles is facilitated if the horizontal electrode faces a magnet, which induces the revolution of bubbles between the electrodes. However, the magnetic field does not increase the current density effectively if the electrodes are more than 5 cm apart. A paramagnetic (platinum) electrode has a more significant effect on bubble locomotion than a diamagnetic (graphite) material and is able to increase the efficiency of electrolysis more effectively when a perpendicular magnetic field is applied. The conductivity of platinum electrodes that face a magnet increases if the distance between the electrodes is less than 4 cm, but the conductivity of graphite electrodes does not increase until the inter-electrode distance is reduced to 2 cm. On the other hand, horizontal graphite electrodes that are subjected to a perpendicular magnetic field will generate a higher gas production rate than a platinum electrode without a magnetic field if the inter-electrode distance is less than 1 cm.