Magnetically Enhanced Oxygen Evolution Reaction in Mild Alkaline Electrolytes by Building Catalysts on Magnetic Frame

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Alkaline water splitting for oxygen evolution reaction (OER) is limited by hydroxide ion (OH) consumption at high current densities.
• High OH concentrations enhance OER but cause system corrosion.
• Developing efficient OER catalysts in low OH concentrations is crucial for practical applications.

Purpose of the Study:

• To enhance catalytic activity for OER in low hydroxide concentrations.
• To investigate the use of magnetic convection for improved OER performance.
• To demonstrate a catalyst-on-magnetic-frame (CMF) strategy for efficient water splitting.

Main Methods:

• Fabrication of a CMF system with CoFeOx nanograins on magnetic Ni foam.
• Testing OER performance under varying magnetic field strengths.
• Evaluating water-splitting performance in low KOH concentrations with magnetic field application.

Main Results:

• The CoFeOx@NF catalyst showed a ~90% OER current enhancement under a 400 mT magnetic field.
• The system demonstrated durability over 120 hours.
• Water-splitting performance improved by up to 45% in 1 M KOH due to magnetic field application, matching performance in 2 M KOH.

Conclusions:

• The CMF strategy effectively utilizes local magnetic convection to enhance OER catalytic activity in low OH concentrations.
• This approach offers a promising alternative to high corrosive electrolyte concentrations for efficient water splitting.
• The catalyst-on-magnetic-frame strategy improves catalyst utilization and OER efficiency.