CHANGWON, South Korea — A new catalyst designed by researchers in South Korea has demonstrated an unusual combination of activity and durability that could help address one of green hydrogen’s most persistent challenges: the gradual breakdown of materials inside water electrolyzers. In tests conducted on a practical three-cell anion exchange membrane water electrolysis stack, the catalyst operated continuously for 3,000 hours—roughly four months—with less than 2% performance degradation. The key to its stability is an atomic-scale restructuring of platinum and nickel that prevents nickel from dissolving during hydrogen production.
The work was led by Principal Researcher Sung Mook Choi of the Korea Institute of Materials Science (KIMS), in collaboration with teams headed by Professor Min Ho Seo of Pukyong National University and Professor Won Bae Kim of Pohang University of Science and Technology. Their catalyst, an ordered platinum–nickel, or PtNi, material, was developed for the hydrogen evolution reaction at the cathode of an anion exchange membrane water electrolyzer. The findings, published in Carbon Energy, offer a potential route toward longer-lasting electrolyzers that use less precious metal while maintaining the high reaction rates needed for industrial hydrogen production.
Water electrolysis separates water into hydrogen and oxygen using electricity. When that electricity comes from renewable sources such as wind or solar power, the process can produce green hydrogen without directly emitting carbon dioxide. Anion exchange membrane water electrolysis is particularly attractive because it operates under alkaline conditions and may reduce dependence on expensive platinum-group metals compared with traditional proton exchange membrane systems. However, alkaline environments make the hydrogen evolution reaction kinetically slower, meaning that highly active catalysts are required to produce hydrogen efficiently at commercially useful current densities.
Platinum is among the most effective materials for driving hydrogen evolution, but its cost and limited availability create obstacles to large-scale deployment. Alloying platinum with nickel can reduce the amount of platinum required and can also modify the catalyst’s electronic structure in ways that improve hydrogen production. The problem is that nickel is chemically less stable than platinum under operating conditions. During extended electrolysis, nickel atoms can leave the alloy and enter the surrounding electrolyte as dissolved ions or hydroxide-containing species. As nickel is removed, the catalyst’s composition, surface structure and electronic properties change, gradually reducing its ability to generate hydrogen.
The Korean research team addressed this problem by controlling not only the chemical composition of the catalyst, but also the precise arrangement of its atoms. In a conventional disordered PtNi alloy, platinum and nickel atoms occupy lattice sites in a largely random pattern. This random structure can contain configurations in which nickel is relatively weakly bound and therefore vulnerable to dissolution. The new catalyst uses an ordered intermetallic structure, in which platinum and nickel occupy well-defined positions within the crystal lattice. According to the researchers’ computational analysis, this arrangement strengthens the stabilization of nickel and raises its resistance to leaching under alkaline electrolysis conditions.
The catalyst was prepared through a two-stage process. First, platinum and nickel precursors were chemically reduced at low temperature using sodium borohydride, or NaBH4, producing a material in which the two elements were initially mixed without long-range atomic order. The powder was then heat-treated under a nitrogen atmosphere. This controlled thermal treatment gave the atoms enough mobility to rearrange into an ordered configuration while shielding the material from unwanted reactions with oxygen in the air. The resulting catalyst was deposited on an electrode and installed at the cathode, where water is converted into hydrogen through a sequence of electrochemical steps involving water molecules, electrons and adsorbed hydrogen intermediates.
The difference between the ordered and disordered materials became especially clear after durability testing. The conventional disordered catalyst lost approximately 54% of its original nickel content, indicating extensive dissolution during operation. By contrast, the ordered PtNi catalyst lost only about 9% of its nickel. This substantial reduction in leaching suggests that the crystal structure acts as an atomic-scale anchor, holding nickel within the alloy and preserving the electronic environment responsible for catalytic activity. Because the active material remains more chemically intact, the electrode can continue to promote hydrogen evolution without undergoing the rapid compositional drift that typically accelerates performance loss.
The researchers then moved beyond small-scale electrochemical measurements and tested the catalyst in a large-area three-cell stack with an active area of 64 square centimeters. This step is important because catalysts that perform well in laboratory half-cell experiments often encounter new challenges when incorporated into membrane assemblies and connected in multi-cell systems. Larger devices introduce factors such as uneven water distribution, gas management, electrical resistance, temperature gradients and fluctuations in operating conditions. Despite these practical complications, the ordered PtNi catalyst maintained stable operation for 3,000 hours, with performance degradation remaining below 2%. The result provides unusually strong evidence that atomic ordering can translate from a materials-science concept into a working electrolyzer architecture.
The advance could have consequences beyond catalyst lifetime. In commercial hydrogen facilities, frequent replacement of degraded components raises maintenance expenses, interrupts production and complicates the integration of electrolyzers with intermittent renewable power. A catalyst that retains its structure for longer periods could lower the cost of hydrogen by extending operating intervals and reducing the need for repairs. The ordered PtNi design also provides a way to reduce platinum loading without abandoning the high intrinsic activity associated with platinum. The team says the same strategy may be adaptable to other platinum–transition-metal catalysts used in fuel cells, electrolyzers and broader electrochemical energy technologies.
“Our study is significant because we used computational science to explain how atomic ordering suppresses nickel leaching under anion exchange membrane water electrolysis conditions and then experimentally validated the mechanism through detailed catalyst analysis and 3,000 hours of operation in a commercially relevant large-area three-cell stack,” said Sung Mook Choi, principal researcher and project leader at KIMS. The researchers are now working to reduce precious-metal loading further, improve the uniformity of large-area electrode manufacturing and optimize stack operating conditions. They also plan to examine how renewable-energy-driven load fluctuations affect the catalyst and to identify the detailed mechanisms responsible for degradation during longer-term operation. If those efforts succeed, locking atoms into place could become an important design principle for making green hydrogen systems more durable, affordable and ready for industrial deployment.
Subject of Research: Atomic ordering in platinum–nickel electrocatalysts for durable anion exchange membrane water electrolysis and green hydrogen production.
Article Title: Locking Ni Atoms in Ordered PtNi for Durable Hydrogen Production: From Electrocatalyst Design to Practical AEMWE Stack Validation
News Publication Date: 1-Jul-2026
Web References: Korea Institute of Materials Science (KIMS); https://doi.org/10.1002/cey2.70265
References: Choi, S. M. et al., “Locking Ni Atoms in Ordered PtNi for Durable Hydrogen Production: From Electrocatalyst Design to Practical AEMWE Stack Validation,” Carbon Energy, DOI: 10.1002/cey2.70265.
Image Credits: Korea Institute of Materials Science (KIMS)
Keywords
Green hydrogen, water electrolysis, anion exchange membrane water electrolysis, AEMWE, platinum–nickel catalyst, PtNi, atomic ordering, nickel leaching, hydrogen evolution reaction, electrocatalysis, electrolyzer durability, renewable energy, fuel cells, electrochemical energy systems
Tags: anion exchange membrane water electrolysisatomic-scale catalyst restructuringdurable platinum-nickel catalystelectrode material degradation preventiongreen hydrogen technologyhigh-performance electrolysis cellshydrogen production sustainabilityindustrial hydrogen generationlong-term catalyst stabilityplatinum alloy catalystsrenewable energy hydrogen productionwater electrolysis efficiency
