| Sep 18, 2025 |
Researchers report a ruthenium-based nanocatalyst that resists chloride corrosion and enables efficient hydrogen production directly from seawater in lab tests.
(Nanowerk News) The growing global demand for clean energy and rising concerns over climate change have intensified the search for sustainable alternatives. Hydrogen emerges as a promising solution due to its high energy density and zero-carbon emissions. Among production methods, alkaline water electrolysis is efficient and environmentally friendly; however, its dependence on freshwater limits large-scale implementation. Seawater electrolysis offers a practical alternative by tapping Earth’s abundant water resources but contains high chloride concentrations that accelerate catalyst corrosion and reduce efficiency, posing a significant challenge for sustainable hydrogen generation.
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To address this problem, a researcher team led by Assistant Professor Haeseong Jang, Department of Advanced Materials Engineering, Chung-Ang University, and Professor Xien Liu, Department of Chemical Engineering, Qingdao University of Science and Technology, aimed to develop a robust and cost-effective electrocatalyst capable of high-performance hydrogen evolution in saline environments.
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Dr. Jang shares the motivation behind this study, “Alkaline water electrolysis, though economically attractive due to the use of inexpensive non-precious metal catalysts, faces significant challenges, including slow hydrogen evolution reaction (HER) kinetics and corrosion problems in real-world environments that hinder commercialization. Our research is driven by the mission to develop economically viable and stable clean hydrogen production technology to overcome these critical barriers.”
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The findings of their study were published in Advanced Functional Materials (“g-C3N4‐Mediated Synthesis of Ru Crystalline/Amorphous Heterostructures on N‐Doped Carbon for Efficient and Chloride‐Resistant Alkaline HER”).
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The team designed a ruthenium (Ru)-based catalyst that balances activity, stability, and chloride-corrosion resistance, overcoming limitations of conventional platinum or Ru catalysts in alkaline and seawater electrolysis. They employed a g-C3N4-mediated pyrolysis strategy to synthesize nitrogen-doped carbon-supported Ru nanoclusters with a crystalline–amorphous heterostructure (a/c-Ru@NC).
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g-C3N4 serves as both a nitrogen source and a scaffold that anchors Ru³⁺ ions through N-coordination sites. During pyrolysis, reductive gases released from g-C3N4 reduce Ru³⁺ in situ to metallic Ru nanoparticles, while Ru–N bonding disrupts atomic order in the core, forming an amorphous Ru phase.
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Surface Ru atoms simultaneously crystallize, producing a stable crystalline–amorphous junction. This architecture ensures ultrafine Ru dispersion (~2.27 nm), electron-deficient active sites, and compressive lattice strain.
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Electrochemical testing demonstrated outstanding HER performance. In 1.0 M KOH, a/c-Ru@NC exhibited an overpotential of just 15 mV at 10 mA cm⁻². Durability was confirmed with stable operation over 250 hours. Crucially, the catalyst exhibited exceptional chloride corrosion resistance with only 8 mV performance degradation and stable operation over 100 hours in simulated seawater, outperforming commercial Pt/C and Ru/C.
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The study highlights several advantages. The crystalline–amorphous heterostructure synergistically combines abundant active sites with optimized electron transport. The nitrogen-doped carbon support prevents Ru oxidation and agglomeration. The overall design provides exceptional chloride-corrosion resistance. Together, these features enable cost-effective, scalable hydrogen production directly from seawater. This approach reduces reliance on freshwater and fossil fuels while supporting decarbonization across energy-intensive sectors.
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Prof. Liu emphasizes, “Our breakthrough enables seawater electrolysis for direct hydrogen production from seawater using chloride-resistant catalysts, opening up vast oceanic resources for clean energy generation.” He adds, “The enhanced alkaline water electrolysis systems demonstrate remarkable economic viability with 37-fold higher mass activity compared to commercial Pt catalysts, making hydrogen production significantly more cost-effective.”
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In conclusion, this work establishes a g-C3N4-mediated heterostructuring strategy that simultaneously addresses activity, stability, and corrosion challenges in Ru-based electrocatalysts. Dr. Jang notes, “Our technology will accelerate climate change mitigation efforts by enabling rapid decarbonization of transportation, industrial, and power generation sectors. The environmental improvements include significant reductions in air pollution and the establishment of comprehensive sustainable energy infrastructure.”
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By enabling efficient and durable seawater electrolysis, this study provides a blueprint for sustainable hydrogen generation from abundant oceanic resources, paving the way for large-scale, green hydrogen infrastructure.
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