Self-supported Fe,Mn-CoCH/NF electrocatalyst for oxygen evolution reaction.

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• The oxygen evolution reaction (OER) is critical for efficient hydrogen production via water electrolysis (WE).
• Cobalt carbonate hydroxide (CoCH) offers robust structural stability for alkaline OER.
• Developing advanced catalysts is essential to improve WE efficiency.

Purpose of the Study:

• To synthesize and characterize a Fe and Mn co-modified CoCH catalyst on nickel foam (Fe,Mn-CoCH/NF).
• To investigate the enhanced OER catalytic activity and stability of the modified catalyst.
• To evaluate the catalyst's performance in overall water splitting (OWS) and seawater electrolysis.

Main Methods:

• Urchin-like CoCH used as a precursor template for catalyst synthesis.
• Mn-doping and surface Fe-modification strategies applied to CoCH on nickel foam.
• Electrochemical characterization to assess OER activity, overpotential, and stability.

Main Results:

• The hierarchical Fe,Mn-CoCH/NF structure improved active site exposure and electron/mass transport.
• Fe and Mn incorporation optimized the d-band center and facilitated the lattice oxygen mechanism (LOM).
• Fe,Mn-CoCH/NF demonstrated a reduced overpotential (204 mV at 10 mA cm⁻²) and excellent stability in alkaline electrolyte.
• An OWS system using Fe,Mn-CoCH/NF achieved efficient splitting at a low cell voltage (1.49 V at 10 mA cm⁻²).
• The catalyst maintained high activity and stability in alkaline seawater electrolysis, mitigating corrosion and Cl⁻ effects.

Conclusions:

• Fe,Mn-CoCH/NF is a highly effective catalyst for alkaline OER and OWS.
• The catalyst's hierarchical structure and elemental modification enhance intrinsic activity and durability.
• The developed catalyst shows promise for efficient hydrogen production from seawater.