Researchers at Tohoku University have developed a novel catalyst structure aimed at enhancing the efficiency and cost-effectiveness of hydrogen production through water electrolysis. The catalyst material comprises mesoporous single-crystalline Co3O4 doped with atomically dispersed iridium, specifically engineered to improve performance in the acidic oxygen evolution reaction (OER). Iridium, known for its exceptional performance in the OER, is often hindered by its scarcity and high cost, posing challenges to widespread implementation of electrolyzer technologies. This study introduces a material design that allows for high iridium loading without forming large clusters, thereby optimizing iridium utilization at the atomic scale. The catalyst's mesoporous spinel structure supports a high iridium loading, enabling the creation of active Co-Ir bridge sites that exhibit superior activity under acidic OER conditions. Computational analysis revealed that iridium doping reactivates the Co sites by countering passivation by oxygen intermediates, thereby enhancing the catalyst's structural stability. Notably, the leaching of iridium and cobalt during reactions was significantly reduced compared to traditional catalysts, with a decrease in material loss by approximately one-fourth and one-fifth, respectively. The catalyst also demonstrated stable performance for over 100 hours, maintaining a low overpotential. The research integrated experimental data with computational modeling, with results shared through the Digital Catalysis Platform developed by the Hao Li Lab. This work, supported by the Tohoku University Support Program, sets the stage for future research aimed at optimizing doping levels, scaling up synthesis processes, and exploring commercial integration of the catalyst into electrolyzer systems.