Microwave-assisted facile synthesis of cobalt-iron oxide nanocomposites for oxygen production using alkaline anion exchange membrane water electrolysis

In this study, a rapid, scalable, and cost-effective method was developed for synthesizing cobalt-iron metal oxide catalysts for water electrolysis. Cobalt-iron metal oxide catalysts were synthesized using the microwave-assisted hydrothermal methods by varying the molar ratios of cobalt and iron. When the cobalt to iron ratio was 2:1, its electrolytic cell yielded the onset potential of only 1.56 V at 10 mA cm(-2), which is close to the thermodynamically reversible potential. When its cell potential was at 1.8 V, the cell current density was approximately 130 mA cm(-2). The results of the stability test showed a steady-state cell current density of 130 mA cm(-2) and remained constant for more than 16 h at a continuous cell potential of 1.8 V. Compared with other catalysts, cobalt-iron metal oxide catalysts showed lower overpotential and lower Tafel slope than did conventional precious metal catalysts such as PtO2 and IrO2. Cobalt-iron metal oxide catalysts serve as an inexpensive route to large-scale commercialization through facile synthesis for enhanced electrochemical water splitting. (C ) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.