South Korean researchers have introduced a cheaper, more efficient way to produce clean green hydrogen.A research team led by Professor Jinwoo Lee at the Korea Advanced Institute of Science and Technology (KAIST) announced a new water electrolysis catalyst built around an “atom-layer neighbor” architecture. The design gathers tiny groups of three or four ruthenium (Ru) atoms together into a single-atom-thick layer anchored to a tungsten carbide support.Interestingly, the catalyst matches the hydrogen output of commercial platinum catalysts while slashing precious metal use by 75 percent. In a 500-hour continuous test, the catalyst proved highly durable, cutting performance degradation in half.Reducing reliance on expensive metalsWater electrolysis uses renewable electricity to split water into low-emission green hydrogen and oxygen. High reliance on costly precious metal catalysts remains a major hurdle for this process. Hence, new technologies are needed that maintain high performance and even reduce expensive metal usage. The team developed a solution by arranging ruthenium atoms into tiny, efficient groups rather than large, wasteful clusters. In typical catalysts, precious metals form three-dimensional clusters. Most of the valuable metal stays buried inside the particle, completely isolated from the water it is meant to split. It is a wasteful design.Scientists previously tried fixing this with “single-atom catalysts,” scattering individual metal atoms across a surface so every atom is exposed. But this design was also not completely beneficial. Splitting water isn’t a solo job; it requires multiple adjacent atoms to work together to move electrons and drive intermediate chemical steps. Single, isolated atoms simply can’t cooperate.KAIST’s “atom-layer neighbor” structure solves a key limitation in catalyst design. The architecture clusters ruthenium atoms into small, flat groups, keeping every atom exposed on the surface. This unique layout lets neighboring atoms work together and even maximizes active-site exposure. It boosts performance without wasting precious metal.The team also designed the immediate chemical environment surrounding the active ruthenium sites.Researchers altered water molecule interactions at the catalytic site through the introduction of hydroxyl species to the support surface. These surface groups reinforce a tight hydrogen-bonding network in the surrounding liquid, enabling protons to move rapidly toward active reaction sites. Tuning both the metal structure and the surrounding water environment allows the entire hydrogen-producing reaction to proceed with minimal resistance.Catalyst testingDuring testing in an anion-exchange membrane water electrolyzer cell at 80°C (176°F) and 2.0 V, the catalyst delivered a current density of 9.82 A/cm². This high current density indicates a rapid hydrogen generation rate. The result proves that the new catalyst can drive fast, efficient chemical reactions under realistic operating conditions.The KAIST ruthenium catalyst worked well in all key metrics. It reduced precious-metal use to just 25 percent of the baseline while delivering four times the catalytic activity per unit mass. The catalyst also shows superior durability, cutting performance loss in half during a 500-hour continuous-operation test.This extra durability lowers initial costs and reduces maintenance expenses over time.While larger-scale trials under fluctuating renewable power conditions remain the next step, the team hopes the technique offers a scalable solution for making clean hydrogen economically viable.The study was published in the journal Nature Communications.