Mn-doped Sequentially Electrodeposited Co-based Oxygen Evolution Catalyst for Efficient Anion Exchange Membrane Water...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• High-performance and durable oxygen evolution reaction (OER) catalysts are crucial for efficient green hydrogen production using anion exchange membrane water electrolysis (AEMWE).
• Nonprecious metal catalysts are sought after to reduce the cost of water electrolysis.

Purpose of the Study:

• To design and synthesize novel Mn-doped Co-based OER catalysts supported on FeO(OH) (FCM) for enhanced activity and durability in AEMWE.
• To investigate the effect of Mn doping on the structural and electrochemical properties of Co-based OER catalysts.

Main Methods:

• Synthesis of a series of Mn-doped Co-based catalysts supported on FeO(OH).
• Electrochemical characterization including OER activity, overpotential, and Tafel slope measurements under half-cell conditions.
• In situ Raman spectroscopy to confirm structural conversion during OER.
• Evaluation of catalyst performance in an anion exchange membrane water electrolysis (AEMWE) single-cell system.

Main Results:

• Mn doping effectively reduced Co oxide particle size, increasing the active surface area.
• Mn doping induced oxygen vacancies, facilitating efficient structural conversion during OER, confirmed by in situ Raman spectroscopy.
• The optimal catalyst achieved an overpotential of 234.4 mV at 10 mA cm⁻² and a Tafel slope of 37.2 mV dec⁻¹.
• In the AEMWE single-cell system, the catalyst demonstrated a current density of 1560 mA cm⁻² at 1.8 V at 60 °C.
• Exceptional durability was observed with a degradation rate of 0.4 mV h⁻¹ over 500 hours at 500 mA cm⁻².

Conclusions:

• Mn-doped Co-based catalysts supported on FeO(OH) represent a significant advancement in nonprecious-metal OER catalysts.
• The developed catalyst exhibits high activity, excellent durability, and potential for cost-effective green hydrogen production via AEMWE.