Active sites and optimization of mixed copper-cobalt oxide anodes for anion exchange membrane water electrolysis

The optimization of the catalysts incorporated to the electrodes for anion exchange membrane water electmlysers is a key issue to maximize their performance through the improvement of the oxygen evolution reaction (OER) yield. In this work, we show that the modification of the microstructure and the chemical properties of a mixed copper-cobalt oxide anode may contribute to increase the activity of this reaction. For this purpose, the OER has been systematically studied, either in a half cell or in a membrane electrode assembly configuration, as a function of the load and agglomeration degree of the catalysts used as electrodes, as prepared on a carbon paper support by magnetron sputtering deposition in an oblique angle configuration. Chemical analysis by X-ray absorption spectroscopy and electrochemical analysis by cyclic voltammetry and impedance spectroscopy have shown that cobalt-copper mixed oxide catalysts with a 1.8 Co/Cu atomic ratio and about one micron equivalent thickness maximizes the cell performance. The chemical, structural and microstructural factors controlling the final behaviour of these anodes and accounting for this maximization of the reaction yield are discussed on the basis of these characterization results and as a function of preparation variables of the electrodes and operating conditions of the cell.

Automated summary

The optimization of catalysts in anion exchange membrane water electrolyzers is crucial for improving the activity of the oxygen evolution reaction. Research has shown that modifying the microstructure and chemical properties of mixed copper-cobalt oxide anodes can increase the reaction activity.