Spin-Selective Coupling in Mott-Schottky Er₂ O₃ -Co Boosts Electrocatalytic Oxygen Reduction

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Alkaline oxygen reduction reaction (ORR) is crucial for electrochemical energy conversion.
• Overcoming thermodynamic limitations in ORR via spin regulation is a significant challenge.
• Developing efficient electrocatalysts is key to advancing energy technologies.

Purpose of the Study:

• To design and synthesize a novel Mott-Schottky catalyst for enhanced ORR performance.
• To investigate the mechanism of spin-selective coupling for ORR improvement.
• To demonstrate the practical application of the catalyst in Zn-air batteries.

Main Methods:

• Fabrication of Er2O3-Co nanoparticles uniformly implanted into carbon nanofibers (Er2O3-Co/CNF).
• Electrochemical characterization of the catalyst's ORR activity, including half-wave and onset potentials.
• Theoretical calculations (e.g., DFT) to elucidate the electronic structure and orbital coupling effects.
• Testing the catalyst's performance as an air-cathode in Zn-air batteries.

Main Results:

• The optimized Er2O3-Co/CNF catalyst exhibited superior ORR performance compared to individual components.
• Achieved a high half-wave potential of 0.835 V vs RHE and onset potential of 0.989 V vs RHE.
• Theoretical analysis revealed Er(4f)-O(2p)-Co(3d) gradient orbital coupling optimizes the electronic structure of Co.
• Demonstrated a spin-selective coupling channel for electron transition, lowering the energy gap for the rate-limiting step.
• Attained a theoretical limiting potential of 0.77 V vs RHE for the Er2O3-Co active site.

Conclusions:

• The Er2O3-Co/CNF catalyst effectively enhances ORR through engineered spin-selective coupling.
• Gradient orbital coupling induced by Er2O3 plays a critical role in optimizing Co's electronic structure for ORR.
• The catalyst shows promising potential for practical applications, particularly in Zn-air batteries.
• This work provides new insights for designing efficient ORR electrocatalysts using rare-earth oxides to engineer spin properties.