Deactivation of Co3O4 acidic OER catalyst. Credit: Yong Wang et al.

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. A new study in the Journal of the American Chemical Society proposes a solution using 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 , 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 more than 100 hours with an overpotential (畏鈧佲個) of just 248 mV.

  • Electrocatalysis OER of H-Ir@Co3O4in 0.5 M H2SO4. Credit: Yong Wang et al.

  • DFT calculations of H-Ir@Co3O4. Credit: Yong Wang et al.

"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 with , and key findings are available through the , a resource developed by the Hao Li Lab to support discovery. Future research will focus on tuning the doping level, scaling up the synthesis process, and exploring integration into commercial electrolyzer systems.

More information: Yong Wang et al, Mesoporous Single-Crystalline Particles as Robust and Efficient Acidic Oxygen Evolution Catalysts, Journal of the American Chemical Society (2025).

Journal information: Journal of the American Chemical Society

Provided by Tohoku University