A defect-rich silver electrode with nickel hydroxide nanoparticles for alkaline hydrogen evolution reaction

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Developing efficient catalysts for the hydrogen evolution reaction (HER) is critical for industrial water electrolysis.
• Current catalysts often face challenges with cost, activity, and long-term stability.

Purpose of the Study:

• To engineer a low-cost, highly active, and durable catalyst for the alkaline HER using a scalable fabrication method.
• To investigate the performance and underlying mechanisms of silver/nickel hydroxide (Ag/Ni(OH)₂) electrodes prepared via cold-pressing.

Main Methods:

• Fabrication of Ag/Ni(OH)₂ electrodes using a rapid and scalable cold-press technique.
• Electrochemical characterization of the catalyst's activity and durability in alkaline media (1 M KOH).
• Mechanistic studies using kinetic isotope effect (KIE) and tert-butanol (TBA) quenching experiments.

Main Results:

• The self-supported Ag/Ni(OH)₂ catalyst exhibited high activity with an overpotential of 66 mV at 10 mA cm^-2.
• Excellent long-term durability was observed, maintaining performance during 200 hours of continuous reaction at 100 mA cm^-2.
• Mechanistic studies indicated accelerated water dissociation at the Ag/Ni(OH)₂ interface and optimized hydrogen adsorption/desorption.

Conclusions:

• The cold-press method is a versatile strategy for producing highly efficient and stable alkaline HER catalysts.
• The defect-rich Ag substrate and Ag/Ni(OH)₂ interfaces contribute significantly to the catalyst's performance.
• This approach holds promise for industrial applications in water electrolysis.