Magnetic field-assisted water splitting at ternary NiCoFe magnetic Nanocatalysts: Optimization study

Abstract

This study addresses the enhanced splitting of water into H2 and O2 assisted with applied magnetic field at ternary NiCoFe catalyst. The catalyst's activity towards water electrolysis is enhanced in the presence of AC-induced magnetic field (B = 720 μT) and approaches the performance of Pt/C∥IrO2. That is the overpotential at a current density of 10 mA cm−2 (η10) is reduced by 90 mV and 210 mV for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), respectively. Besides, a significant reduction in the cell voltage of 0.3 V and a power saving of 215.6 kWh during the production of one kg of H2 are obtained when AC magnetic field of 720 μT is applied. A markedly high stability of the catalyst is obtained under magnetic field during a prolonged electrolysis. The magnetohydrodynamic effect is believed to drive water electrolysis at NiCoFe film by reducing the ohmic potential drop across the electrode/solution interface, and increases the rate of charge transfer at the catalyst surface. The results are explained by capacitance measurements revealing maximum capacitance of NiFeCo catalyst in the presence of AC magnetic flux of 720 μT. Thus, favourable adsorption conditions lead to accelerated kinetics of OER and HER.