Atomic Cerium Boosts Oxygen Evolution via Electronic Coupling in Defective CoFe-Layered Double Hydroxides

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Efficient and durable nonprecious electrocatalysts are crucial for sustainable hydrogen production via the oxygen evolution reaction (OER).
• Layered double hydroxides (LDHs) are promising supports, but enhancing their catalytic activity and stability remains a challenge.

Purpose of the Study:

• To engineer a defective CoFe-LDH support for stabilizing isolated cerium single atoms.
• To investigate the electronic interactions and catalytic mechanisms of the resulting Ce-single-atom catalyst for OER.

Main Methods:

• One-step coprecipitation synthesis of the Ce-single-atom catalyst (Ce_0.2CoFe-LDH).
• Characterization using atomic-resolution electron microscopy and synchrotron-based X-ray spectroscopy.
• Electrochemical measurements and first-principles calculations.

Main Results:

• Atomic dispersion of Ce³⁺ at cation vacancy sites within the LDH matrix was confirmed.
• Strong electronic interactions between Ce and Co/Fe sites enhanced transition metal valence states and redox cycling.
• The optimized catalyst achieved a low overpotential (227 mV at 10 mA·cm^-2), a Tafel slope of 48.3 mV·dec^-1, and excellent stability (>50 h).

Conclusions:

• Defect-driven single-atom anchoring effectively modulates electronic structure and optimizes reaction pathways in LDH electrocatalysts.
• The Ce-single-atom catalyst demonstrates high performance and stability for the oxygen evolution reaction.
• This strategy provides valuable insights for designing advanced energy conversion materials.