Chung-Ang University develops chloride resistant nonacatalysts

Seawater electrolysis offers a practical alternative by tapping Earth's abundant water resources, but high chloride concentrations accelerate catalyst corrosion and reduce efficiency, posing significant challenges for sustainable hydrogen generation.

To address this, a research team led by Assistant Professor Haeseong Jang at Chung-Ang University and Professor Xien Liu at Qingdao University of Science and Technology, developed a robust and cost-effective electrocatalyst capable of high-performance hydrogen evolution in saline environments.

Dr Jang explained: "Alkaline water electrolysis, though economically attractive due to inexpensive non-precious metal catalysts, faces significant challenges, including slow hydrogen evolution reaction (HER) kinetics and corrosion problems in real-world environments that hinder commercialisation. Our research is driven by the mission to develop economically viable and stable clean hydrogen production technology to overcome these critical barriers."

They designed a ruthenium (Ru)-based catalyst that overcomes 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). g-C3N4 serves as 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, while Ru–N bonding disrupts atomic order in the core, forming an amorphous Ru phase. Surface Ru atoms simultaneously crystallise, producing a stable crystalline–amorphous junction. This architecture ensures ultrafine Ru dispersion, electron-deficient active sites, and compressive lattice strain.

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.

The study highlights several advantages. The a/c-Ru@NC synergistically combines abundant active sites with optimised 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 decarbonisation across energy-intensive sectors.

Professor Liu emphasised: "Our breakthrough enables seawater electrolysis for direct hydrogen production from seawater using chloride-resistant catalysts, opening up vast oceanic resources for clean energy generation. 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."

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 noted: "Our technology will accelerate climate change mitigation efforts by enabling rapid decarbonisation of transportation, industrial, and power generation sectors."

By enabling efficient and durable seawater electrolysis, this study provides a blueprint for sustainable hydrogen generation from oceanic resources, paving the way for large scale, green hydrogen infrastructure.

Read the article online at: https://www.globalhydrogenreview.com/hydrogen/19092025/chung-ang-university-develop-chloride-resistant-nonacatalysts/