Steel Based Precious Group Metal-Free High-Performance Electrodes for Alkaline Exchange Membrane Water Electrolysis

Area of Science:

• Electrochemistry
• Materials Science
• Sustainable Energy

Background:

• Platinum-group metals (PGMs) are expensive, hindering cost-effective alkaline water electrolysis.
• Development of PGM-free electrodes is crucial for scalable hydrogen production.
• Anion exchange membrane water electrolyzers (AEMWEs) offer a promising PGM-free alternative.

Purpose of the Study:

• To develop and characterize steel-based electrodes for a fully PGM-free and ionomer-free AEMWE.
• To evaluate the electrocatalytic performance of the novel electrodes for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER).
• To demonstrate the performance and stability of an integrated AEMWE single cell using these electrodes.

Main Methods:

• Synthesis of a hierarchical NiMo@ss catalyst via hydrothermal NiMo growth on Ni-coated stainless steel (ss) followed by reductive annealing.
• Electrochemical characterization of HER and OER activity in alkaline media.
• Fabrication and testing of a 5x5 cm² PGM-free AEMWE single cell.

Main Results:

• The NiMo@ss catalyst exhibited enhanced HER kinetics with an overpotential of -70 mV at -10 mA cm⁻².
• A Ni-deposited and anodized porous transport layer showed improved OER activity with an overpotential of 284 mV at 10 mA cm⁻².
• The integrated AEMWE achieved a current density of 1 A cm⁻² at 1.92 V (1 M KOH, 60 °C) and demonstrated stable operation for 60 hours under dynamic conditions.

Conclusions:

• Engineered steel-supported electrodes offer a viable pathway for cost-effective, noble-metal-free hydrogen production.
• The developed PGM-free electrodes enable high performance and stability in AEMWEs.
• This work highlights the potential for scalable and sustainable hydrogen generation.