Researchers led by University of Oregon chemist Paul Kempler have identified dissolved iron impurities as the key factor controlling the degradation of alkaline water electrolyzers during power interruptions — a finding that could point toward a fix for one of green hydrogen's persistent engineering challenges. The paper publishes Sept. 9 in Chem Catalysis.
The finding: Alkaline water electrolyzers, which split water into hydrogen and oxygen using electricity, are known to degrade when their power supply is interrupted and restored — a stability problem that's been difficult to pin down. This new research traces that instability to trace levels of dissolved iron within the system, identifying it as a controlling factor in performance loss during these power transients.
Why it's a problem: Alkaline electrolyzers are the cheapest existing technology for producing hydrogen from electricity, but they're also sensitive to the kind of on-again, off-again power supply that wind and solar generate. That intermittency is inherent to renewable energy, so if electrolyzers can't tolerate it well, it limits how directly they can be paired with renewable sources — a significant bottleneck for scaling up affordable, green hydrogen production.
The application: Because the researchers pinpointed iron impurities as the mechanism, they see a potential path to a solution: rather than eliminating impurities entirely, purifying the system and then reintroducing a controlled, specific amount of iron (or possibly other elements) afterward. If it holds up, this impurity-engineering approach could make electrolyzers more resilient to intermittent power — directly addressing a key barrier to renewable-powered hydrogen production.
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