Accelerating OH^- Transport for 5000-Hour-Stable Kilowatt-Scale Alkaline Water Electrolysis.

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Efficient alkaline water electrolysis (AWE) requires enhanced hydroxide ion (OH-) supply to anode catalysts under high current densities.
• Current AWE systems face limitations in reactant transport, hindering large-scale green hydrogen production.

Purpose of the Study:

• To develop a strategy for improving OH- transport in AWE by manipulating interfacial hydrogen bond networks.
• To investigate the role of rare earth oxide clusters (REOx) in enhancing OH- mobility and oxygen evolution reaction (OER) activity.

Main Methods:

• Incorporation of rare earth oxide clusters (REOx) into NiCo2S4 catalysts to reconfigure interfacial water structures.
• Mechanistic analysis using spectroscopy and electrochemical measurements to study OH- transport and OER mechanisms.
• Assembly and testing of a kilowatt-scale AWE system with a DyOx/NiCo2S4 anode.

Main Results:

• REOx incorporation nearly tripled the OH- transport rate by weakening interactions and promoting a looser interfacial water configuration.
• A linear correlation was observed between isolated water species, OH- transport rates, and OER activity across REOx/NiCo2S4 catalysts.
• The kilowatt-scale AWE system demonstrated stable operation for over 5,000 hours at industrial conditions, producing 1,400 Nm3 of hydrogen.

Conclusions:

• Manipulating the electrode-electrolyte interface with REOx is an effective strategy to enhance OH- transport and OER performance in AWE.
• This approach enables stable, long-term operation of AWE systems for industrial-scale green hydrogen production.
• The findings offer a new pathway for designing advanced catalysts for efficient and sustainable hydrogen generation.