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

Abstract

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.