Electrochemical water electrolysis via the oxygen evolution reaction (OER) is a promising technique for producing hydrogen gas using renewable energy sources. While most commercial electrolyzers currently rely on freshwater feedstocks, large-scale deployment can be constrained by the availability and cost of desalination infrastructure. In contrast, natural seawater—an abundant and virtually inexhaustible resource—offers an attractive alternative feedstock for large-scale electrolysis. However, seawater electrolysis presents significant challenges due to the high concentration of chloride ions, which can trigger competing side reactions such as the chlorine evolution reaction (ClER) and accelerate the corrosion of electrode materials.
In this study, we investigate earth-abundant cobalt-based spinel oxides, which exhibit promising OER activity but are prone to cobalt ion dissolution under the near-neutral pH conditions characteristic of natural seawater. To overcome this limitation, we developed a high-throughput platform capable of synthesizing and screening 96 cobalt-based spinel catalyst compositions per day, enabling rapid identification and optimization of stable, efficient OER catalysts for seawater electrolysis. The most promising composition identified through this screening process will be further evaluated in natural seawater and integrated into membrane electrode assembly (MEA) configurations to assess its practical performance and durability.
