Mixed iridium-tungsten oxides as highly active and stable anode electrode for proton exchange membrane water electrolyzers

Water electrolysis using proton exchange membrane (PEM) technology is one of the most promising processes to produce green hydrogen. However, for its industrialization, the anode catalyst must be improved to provide high activity and stability with low iridium content. In this work, a catalyst consisting of a composite with mixed iridium-tungsten oxides (ca. 30 wt% of iridium, denoted IrOx-WO3) was prepared and tested in a PEM electrolyzer. The performance of this new catalyst was benchmarked with an iridium-based commercial catalyst from Premetek. The results obtained in the rotating disk electrode (RDE) demonstrated that the IrOx-WO3 catalyst can achieve an OER activity of 113.6 mA mgIr-1 at 1.55 VRHE and was stable in 0.1 M HClO4 during 2 h. The prepared catalyst was further studied in a single-cell electrolyzer, according to an EU test protocol, displaying excellent performance indicators with a catalyst load of 0.2 mgIr cm- 2 - 1.69 V @ 1 A cm- 2 and a stability of over 500 h @ 1.5 A cm- 2. Therefore, the prepared catalyst is a promising anode catalyst for PEM electrolyzers.