New porous crystal catalyst offers durable, efficient solution for clean hydrogen production

A new catalyst structure offers a potential pathway toward more cost-effective hydrogen production via water electrolysis. The material centers on mesoporous single-crystalline Co3O4 doped with atomically dispersed iridium (Ir), designed for the acidic oxygen evolution reaction (OER).

Iridium is known for its OER performance but is both scarce and expensive. Efficient use of Ir while maintaining stability is a major challenge for scaling up electrolyzer technologies. This study proposes a solution through a material that maximizes atomic-level efficiency.

The catalyst features a mesoporous spinel structure that allows for high Ir loading (13.8 wt%) without forming large Ir clusters. This configuration enables the formation of Co-Ir bridge sites, which show high intrinsic activity under acidic OER conditions.

Computational analysis indicates that under reaction conditions, oxygen intermediates (O*) fully cover Co3O4 surfaces, which usually passivates Co sites. However, Ir doping reactivates these sites, while simultaneously enhancing the structural integrity of the catalyst.

Leaching of both Ir and Co during reaction was significantly reduced. Compared to conventional Ir/Co3O4 catalysts, Ir and Co loss was lowered to approximately one-fourth and one-fifth, respectively. The catalyst also maintained performance for over 100 hours with an overpotential (η₁₀) of just 248 mV.

"The mesoporous architecture plays a crucial role," explains Professor Hao Li, who led the study. "It provides space for single-atom Ir loading and helps create a stable environment for catalytic activity."

The research combines experimental data with computational modeling, and key findings are available through the Digital Catalysis Platform (www.digcat.org), a resource developed by the Hao Li Lab to support catalyst discovery.

This work was supported by the Tohoku University Support Program. Future research will focus on tuning the doping level, scaling up the synthesis process, and exploring integration into commercial electrolyzer systems.