Plate Nº 16 · recorded September 29, 2026
Chemistry & MaterialsReported finding
Palladium Membrane Lets Hydrogen Through and Keeps Water Out
Korean researchers built a palladium membrane that shuttles hydrogen ions while blocking water, enabling ammonia synthesis fed directly by water instead of hydrogen gas.
By Nathan Brooks3 min read673 words
In brief
- KIER researchers showed a dense palladium membrane transports hydrogen while blocking water and other substances
- The team demonstrated the first electrochemical ammonia synthesis in Korea using water directly as the hydrogen source
- The study appears in Advanced Science (DOI: 10.1002/advs.76415), led by Dr. Jae-Hyung Kim with Seoul National University collaborators
A South Korean research team has found a way to make ammonia synthesis cleaner by solving a stubborn problem in electrochemical devices: unwanted molecules sneaking through the separation membrane.
Researchers at the Korea Institute of Energy Research (KIER) showed that a dense palladium membrane can transport hydrogen from water while blocking everything else. They demonstrated the approach in an ammonia synthesis process that runs on renewable electricity and draws its hydrogen from water rather than fossil fuels. The findings appeared in the journal Advanced Science.
Why membranes matter
Electrochemical cells — devices that use electricity to drive chemical reactions — rely on separation membranes. A membrane keeps reagents, products and solvents in their own compartments while letting ions pass through so the reaction can proceed. Until now, engineers have mostly used polymeric membranes, a class of plastic-based materials that includes ion-exchange membranes.
These polymers contain narrow channels that allow water and ions to pass. But other, unwanted molecules slip through too. Scientists call this problem "crossover," and it can seriously degrade the performance and stability of electrochemical devices.
Conventional membranes force researchers into a trade-off. Tightening the membrane to reduce crossover also slows ion transport, hurting the device in a different way.
The KIER team sidestepped this trade-off by replacing the polymer with a sheet of dense palladium metal. Palladium selectively absorbs hydrogen atoms and carries them across, while refusing passage to virtually everything else.
How the metal shuttle works
The mechanism works like a relay. When the device applies an electric field, hydrogen ions on one side of the palladium membrane pick up electrons and become hydrogen atoms. Those atoms diffuse through the metal to the other side. There, they give up electrons, turn back into hydrogen ions, and enter the solution. Throughout the process, the membrane keeps solvents, reagents and products on either side completely separated.
Applied to ammonia
The KIER team, working with a group led by professor Yun Jeong Hwang at Seoul National University, applied the membrane to electrochemical ammonia synthesis.
Ammonia is a vital industrial chemical, and making it without carbon emissions is a major research goal. Electrochemical synthesis needs hydrogen ions as a key feedstock. The catch: the reaction happens in an organic solvent compartment, and even trace amounts of water in that compartment can significantly reduce efficiency.
Because no previous membrane could carry hydrogen ions while completely excluding water, researchers have predominantly fed these devices hydrogen gas rather than water. Producing that gas usually involves fossil fuels.
The palladium membrane changed the equation. With it, the KIER team ran an electrochemical ammonia synthesis process that uses water directly, instead of hydrogen gas, as the hydrogen source. Powered by renewable energy, the approach minimizes carbon emissions. The team says it is the first in Korea to accomplish this, and the result opens a new direction for research in the field.
Dr. Jae-Hyung Kim, who led the project, said: "This achievement is significant in that our proposed novel ion-transport mechanism provides an effective solution to the crossover issue, which remains a primary barrier to implementing green ammonia synthesis through electrochemical devices."
Kim added: "The developed technology also holds high potential for broader applications across various electrochemical devices that demand even stricter mass separation than ammonia synthesis."
Early days
The published work is a laboratory demonstration rather than an industrial process, and the researchers themselves frame it as a new direction rather than a finished solution. Questions about the membrane's long-term durability, cost at scale, and performance in larger reactors will need answering before the technology reaches industry.
Still, the underlying idea — using a dense metal to transport protons while excluding everything else — addresses one of the field's core problems in a fundamentally different way than polymer engineering. If it proves robust, the concept could extend well beyond ammonia to any electrochemical device that demands strict separation between compartments.
Publication details
Jiyeon Baek et al, "Bipolar Palladium Membrane Enabling Crossover-Free Selective Proton Transport," Advanced Science (2026). DOI: 10.1002/advs.76415
via Phys.org Chemistry (Source)
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