Korean researchers have developed a new platinum-nickel catalyst that can operate continuously for 3,000 hours while maintaining almost all of its performance, potentially addressing one of the biggest challenges facing water electrolysis and green hydrogen production.
The catalyst uses an atomic-scale structure that prevents nickel from dissolving during operation, a process that can cause conventional catalysts to degrade over time. Tested in a large-area three-cell electrolysis stack, the new material showed less than 2% performance degradation after roughly four months of continuous operation.
The researchers explain that the approach could extend catalyst lifetimes, reduce maintenance and replacement costs, and support the development of more commercially viable hydrogen production systems using renewable electricity.
Changing the catalyst at the atomic level
The catalyst was developed for anion exchange membrane water electrolysis, or AEMWE, a technology that produces hydrogen by splitting water under alkaline conditions. AEMWE is attracting attention because it can reduce reliance on expensive precious metals compared with some conventional electrolysis technologies.
The challenge is that the hydrogen evolution reaction is slower in alkaline environments, increasing the need for catalysts that can deliver high activity without rapidly losing performance.
Conventional platinum-nickel catalysts can initially perform well, but nickel gradually dissolves during extended operation. As nickel leaves the material, its composition and electronic structure change, reducing catalytic performance.
The researchers from the Korea Institute of Materials Science (KIMS) addressed this problem by changing how the atoms are arranged, and instead of randomly mixing platinum and nickel, they created an ordered intermetallic structure in which the two elements occupy defined positions in the crystal lattice. Computational modeling indicated that this configuration makes nickel more resistant to dissolution.
The material was synthesized at low temperature and then heat-treated in a nitrogen atmosphere. The process then allowed the initially disordered platinum and nickel atoms to reorganize into the more stable ordered structure.
Four months of continuous hydrogen production
Testing showed a significant difference between the conventional and ordered versions of the catalyst. After durability testing, the conventional material had lost about 54% of its original nickel, while the ordered catalyst lost only about 9%. The researchers then moved beyond laboratory-scale testing and integrated the catalyst into a large-area three-cell stack with an active area of about 99 square inches.
The system operated continuously for 3,000 hours, or about four months – a durability that could be important for the economics of green hydrogen. Catalyst replacement and maintenance can add significantly to operating costs, particularly as electrolyzers are deployed at larger scales and connected to renewable energy sources that can introduce fluctuating operating conditions.
The researchers say the technology could eventually be used in renewable-powered hydrogen facilities, distributed electrolyzers and large-area electrolysis stacks. Furthermore, the atomic-ordering approach could also extend beyond hydrogen production.
The team believes the same atomic-ordering strategy could be applied to other platinum-transition metal catalysts, fuel cells and electrochemical energy systems, likely improving their durability and performance while reducing material degradation during long-term operation.