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

Water electrolysis has gained traction as one of the most promising techniques for green hydrogen production. This process utilizes electrical energy to power an electrolyzer, a reactor that separates water molecules (H2O) into hydrogen (H2) and oxygen (O2). The efficiency of these electrolyzers greatly depends on a specialized membrane designed to prevent the mixing of hydrogen and oxygen gases, which if allowed, could result in explosive reactions. The current industry standard membrane is Nafion, a well-known material that belongs to a category of substances characterized by their persistence in the environment, often referred to as per- and polyfluoroalkyl substances (PFAS).

At Columbia Engineering, a groundbreaking initiative is underway led by chemical engineer Dan Esposito. His team is pioneering a method to replace Nafion membranes with ultra-thin, PFAS-free oxide membranes, potentially reducing the environmental hazards associated with traditional electrolyzers. The research, underpinned by support from the U.S. Department of Energy and in collaboration with industry partners Nel Hydrogen and Forge Nano, seeks to eliminate over 99% of PFAS from electrolyzer systems. This ambitious endeavor highlights a significant leap forward in eco-friendly hydrogen production techniques.

The membrane’s critical role in the electrolyzer’s functionality cannot be overstated. Esposito emphasizes its importance, stating it maintains the critical separation of hydrogen and oxygen gases while allowing protons to pass through. If the membrane fails, not only does the system cease to work, but it can pose significant safety risks. Consequently, Esposito and his research team are dedicated to devising innovative manufacturing techniques that enhance both the efficiency and safety of the proposed oxide membranes.

Notably, the research team has published their findings in the journal ACS Nano, detailing their new approach to creating membranes that are markedly thinner than conventional options. By utilizing silicon dioxide, a less conductive but PFAS-free alternative, the researchers are pushing the boundaries of traditional materials science. The reduced thickness of the membranes, achieved through advanced manufacturing techniques like atomic layer deposition, enhances overall performance, even though silicon dioxide’s baseline conductivity is lower than that of Nafion.

This significant innovation is accentuated by the thickness reduction from approximately 180 microns for Nafion membranes to less than one micron for the new oxide membranes. This is a staggering reduction, with the new membranes being hundreds of times thinner than current standards. Despite the inherent challenges posed by decreased conductivity, the emphasis on membrane thinness is supported by the understanding that resistance relates not merely to material conductivity but also to physical dimensions.

However, a considerably thinner membrane introduces a new set of challenges, particularly concerning structural integrity. Defects such as microscopic cracks or pinholes can compromise membrane performance, leading to hydrogen leakage on the oxygen side — a perilous prospect. Esposito warns that even a few defects per square centimeter can render a membrane entirely unsafe for operational purposes. To address this critical issue, the team has developed an innovative electrochemical approach that specifically targets and seals these defects without risking the membrane’s structural integrity.

Exploiting pulsed voltage applications to instigate selective depositions of nanoscopic plugs within the identified defects showcases the ingenuity of the research team. This method allows for meticulous repair of any holes while preserving low resistance and required thinness, crucial for effective functionality. Esposito’s insight into maintaining pH level stability during the process has proven fundamental, ensuring optimal results without unwanted material deposition on the membrane’s surface.

Laboratory tests have demonstrated thrilling results, with the plugged membranes indicating hydrogen crossover rates up to 100 times lower than that of Nafion, despite their significantly reduced thickness. The substantial implications of these findings could redefine the benchmarks for efficiency and safety in hydrogen production technologies. The team’s commitment to advancing their work indicates a strong trajectory toward commercial applications, transitioning from small-scale tests to prototypes that meet industry demands.

Significantly, while the focus of the research is entrenched in hydrogen production, there are broader applications inherent to this defect-plugging methodology. Potential benefits could arise in various fields, including fuel cells, flow battery development, water treatment processes, and even semiconductor manufacturing. This versatility underscores the multifaceted impact that such innovative research could impart across numerous scientific and engineering disciplines.

Esposito anticipates a future where hydrogen derived from water electrolysis contributes to a larger share of global energy production. Currently, less than 0.1% of hydrogen worldwide is sourced through electrolysis, starkly contrasting with the pressing need for sustainable energy solutions. The endeavor to create high-performance, environmentally responsible membranes is critical as the industry seeks to scale hydrogen production in a sustainable manner.

As the research continues and scales evolve, the significance of Esposito’s findings might reverberate throughout the green technology landscape. The team’s dedication to developing practical solutions for the energy sector exemplifies a hopeful future in which eco-friendly hydrogen production can thrive alongside environmental protection efforts.

This research represents a confluence of innovation, engineering excellence, and environmental stewardship. As such, it lays the groundwork for pioneering strides not only in hydrogen production but also across varied technological fields where such membranes can be effectively utilized. With the world looking for sustainable pathways forward, the implications of this research transcend traditional boundaries, promising a cleaner and more efficient energy future.

Esposito’s vision and the collective efforts of the research team embody the spirit of innovation required to tackle complex global challenges. As they venture into collaboration with industry leaders, the transition from experimental stages to real-world implementation will be closely watched by the scientific community and beyond, with potential ramifications that can reshape our understanding of energy production.

Subject of Research: Replacement of Nafion membranes with PFAS-free oxide membranes for hydrogen electrolyzers
Article Title: Nanoscopic plugs block hydrogen crossover in submicron thick proton-conducting SiO2 membranes for water electrolysis
News Publication Date: October 2023
Web References: https://www.engineering.columbia.edu/academics/departments/chemical-engineering-department
References: DOI: 10.1021/acsnano.5c09555
Image Credits: Esposito Lab

Keywords

Hydrogen production, water electrolysis, Nafion replacement, PFAS-free membranes, silicon dioxide, energy sustainability, electrochemical methods, membrane technology.