Effect of titanium-based supports on the electrochemical activity and stability of iridium nanoparticle catalysts for OER in PEM water electrolyzer

Efficient and stable oxygen evolution reaction catalysts are essential for advancing hydrogen production through water electrolysis. This study investigates the role of titanium-based supports — TiO 2 , TiC, and TiN — in enhancing the activity and stability of iridium (Ir) nanoparticles, focusing on their morphological, chemical, and electrochemical properties. In a half - electrochemical cell, iridium supported on titanium dioxide (Ir/TiO 2 ) and titanium carbide (Ir/TiC) exhibited excellent OER performance with an overpotential of 260 mV and 259 mV at 10 mA cm −2 , respectively, which are comparable to unsupported Ir black nanoparticles (253 mV). In contrast, Ir supported on titanium nitride (Ir/TiN) showed a higher overpotential of 329 mV. The catalytic performance of these materials was further evaluated in a single-cell proton exchange membrane water electrolyzer. Post-mortem analyses of the membrane electrode assemblies revealed support-specific degradation pathways, including oxidation and dissolution processes. The findings highlight the influence of support material properties — such as conductivity, crystallinity, and composition — on the efficiency and durability of Ir nanoparticles. These insights provide a valuable foundation for designing advanced catalytic materials for water electrolyzers.