HKU Engineering Team Unveils Self-Protecting Catalyst Advancing Durable And Affordable Green Hydrogen

An international research team led by Professor Philip C.Y. Chow at The University of Hong Kong (HKU) has unveiled a new catalyst that overcomes a major challenge in producing green hydrogen at scale. This innovation makes the process of producing oxygen efficiently and reliably in the harsh acidic environment used by today’s most promising industrial electrolysers.

Green hydrogen is seen as a clean fuel that can help reduce carbon emissions across industries like steelmaking, chemical production, long-distance transportation, and seasonal energy storage. Proton exchange membrane (PEM) electrolysers are preferred for their compact design and rapid response, but they operate in acidic conditions that are exceptionally demanding on the oxygen evolution reaction (OER) catalyst. Currently, the best catalysts use rare and expensive metals like iridium. Alternative materials often break down quickly, making green hydrogen too expensive for widespread use. Finding a catalyst that’s both durable and affordable is crucial for scaling up green hydrogen production.

The research team’s solution is a new catalyst made with single atoms of ruthenium (a platinum-group metal) spread across tiny particles of manganese oxybromide (Mn7.5O10Br3), also known as Ru‑MOB. During operation, the catalyst “self-adjusts” its surface, forming a thin protective layer of modified manganese dioxide (γ‑MnO2). This dynamic layer acts like a skin that shields the catalyst from damage while remaining highly active, allowing it to produce oxygen efficiently and stay stable over time.

Using advanced testing techniques and computer simulations, the researchers showed that this self‑formed layer guides the chemical reactions down a safer, more efficient pathway. It favours the formation of oxygen directly from water, while preventing destructive reactions that can damage the catalyst.

In laboratory tests, the Ru‑MOB catalyst required only a small extra voltage—just 208.3 millivolts—to produce hydrogen efficiently at a typical current density. It also demonstrated exceptional durability, running for more than 1,400 hours at a standard operating level without significant degradation, and over 200 hours at higher current levels. This combination of high efficiency and long-lasting performance in acidic conditions, while using a minimal amount of ruthenium, is a major step toward making affordable, reliable green hydrogen a reality.

Beyond these impressive performance results, the study offers a powerful blueprint for designing durable catalysts: using a self-reconstructing mechanism and single‑atom tuning to regulate the reactions happen and protect the catalyst during operation.

Professor Philip Chow commented, “This approach can guide the development of the next-generation materials for clean hydrogen and other electrochemical processes, accelerating the adoption of green energy solutions across industries such as shipping, aviation, power grids, and long‑term energy storage.”