The efficiency limitations of water electrolysis remain one of the largest technical and economic barriers to scaling green hydrogen production. While renewable electricity costs have declined sharply over the past decade, the oxygen evolution reaction inside electrolyzers continues to require high energy input, slowing system efficiency and sustaining dependence on expensive precious metal catalysts such as iridium and ruthenium.
A research team led by Sungkyunkwan University and Kyungpook National University claims to have addressed part of that challenge through atomic-level engineering of cobalt oxide nanoclusters designed to activate lattice oxygen directly within the catalytic structure.
The researchers, led by Professor Hyung Mo Jeong and Professor Ji Hoon Lee, reported the development of a non-precious metal catalyst capable of outperforming commercial iridium-based catalysts under certain operating conditions while maintaining stability during extended high-current operation. The work targets one of the central technical constraints in electrochemical hydrogen production.
In proton exchange membrane and alkaline electrolyzers, the oxygen evolution reaction is significantly slower than the hydrogen evolution reaction. That imbalance increases voltage requirements, reduces overall efficiency, and raises electricity consumption during hydrogen production. Because electricity costs account for a substantial share of green hydrogen economics, even modest efficiency gains at the catalyst level can materially affect long-term production costs.
The industry has historically relied on iridium and ruthenium because of their high catalytic activity and stability under harsh electrochemical conditions. However, both metals face severe supply limitations and price volatility.
Iridium, in particular, remains one of the rarest industrial metals globally, with annual production measured in only a few tonnes. Analysts have repeatedly identified iridium availability as a major bottleneck for scaling proton exchange membrane electrolyzer deployment worldwide. As governments and industrial sectors accelerate hydrogen strategies, pressure has intensified to identify lower-cost catalyst alternatives based on more abundant materials.
The Korean research team focused on cobalt oxide, a material already widely studied in electrocatalysis but typically constrained by lower efficiency and limited durability compared with precious metals. Rather than modifying chemical composition alone, the researchers concentrated on atomic bond distance engineering.
Using electrochemical synthesis methods, the team fragmented bulk cobalt oxide into nanoclusters smaller than 2 nanometers and reduced the bond spacing between cobalt and oxygen atoms by approximately 0.1 angstroms. According to the researchers, advanced structural analysis conducted at the Pohang Accelerator Laboratory confirmed that a cobalt-oxygen bond length of 2.03 angstroms created optimal conditions for activating a different catalytic mechanism involving lattice oxygen participation.
That mechanism is significant because conventional oxygen evolution reactions generally rely on surface-adsorbed intermediates during catalytic turnover. Lattice oxygen mechanisms instead involve oxygen atoms embedded directly within the catalyst structure participating in the reaction itself, potentially lowering energy barriers and accelerating reaction kinetics.
Over the past several years, lattice oxygen activation has emerged as a major area of interest in catalyst research because of its theoretical potential to overcome performance limitations associated with conventional adsorption-driven catalytic pathways.
However, controlling lattice oxygen participation without destabilizing catalyst structures has remained difficult. Excessive lattice oxygen activation can accelerate catalyst degradation, trigger structural collapse, or reduce long-term operational stability under industrial conditions. Much of the recent research in the field has therefore focused on balancing catalytic activity with durability.
The Korean team claims its atomic-scale bond engineering approach achieved both. According to the published findings, the catalyst operated at lower energy levels than commercial iridium catalysts while maintaining stable operation for more than 100 hours under high-current conditions. The researchers also reported strong charging stability when the material was applied in zinc-air battery systems, suggesting broader electrochemical applications beyond hydrogen production.
The durability claim is particularly important because catalyst degradation remains one of the most significant commercialization barriers in advanced electrolyzer systems. Laboratory-scale performance improvements frequently fail during long-duration industrial operation where catalysts experience thermal stress, fluctuating current densities, electrolyte corrosion, and structural fatigue over thousands of operating hours. While 100-hour testing represents an early-stage benchmark rather than full industrial validation, stable high-current operation provides a stronger indicator of practical viability than short-cycle laboratory measurements alone.
Scaling nanocluster synthesis from laboratory conditions to industrial manufacturing often introduces reproducibility, cost, and quality-control difficulties. Atomic-level precision engineering that functions under controlled experimental environments can become significantly harder to maintain at commercial production volumes.
Catalyst performance alone does not determine hydrogen production costs. Stack design, membrane durability, power electronics, renewable electricity pricing, balance-of-plant costs, and operational utilization rates all influence commercial hydrogen economics. As a result, even highly promising catalyst breakthroughs often require years of systems-level engineering before translating into meaningful industrial cost reductions.
Rather than relying solely on incremental optimization of existing precious metal systems, research institutions are increasingly pursuing atomic-scale materials engineering strategies designed to fundamentally alter electrochemical reaction pathways. Advances in synchrotron analysis, nanoscale characterization, and computational materials modeling are enabling researchers to manipulate catalytic structures with increasing precision. That transition is becoming strategically important as governments attempt to scale electrolyzer manufacturing capacity while avoiding dependence on scarce critical minerals.
The research, supported by South Korea’s Ministry of Science and ICT and the National Research Foundation of Korea, was published in the journal Applied Catalysis B: Environment and Energy, reflecting growing global competition to develop commercially viable alternatives to precious metal hydrogen catalysts amid accelerating industrial decarbonization efforts.
