Tuning the Spin Density of Cobalt Single-Atom Catalysts for Efficient Oxygen Evolution

Area of Science:

• Materials Science
• Catalysis
• Surface Chemistry

Background:

• Single-atom catalysts (SACs) with magnetic active centers are crucial for electrochemical reactions.
• Understanding the role of electron spin in catalysis is vital for fundamental science and technological advancement.

Purpose of the Study:

• To investigate the correlation between spin density and catalytic activity in ferromagnetic single-atom catalysts.
• To explore the oxygen evolution reaction (OER) using a model system of single cobalt atoms on TaS2 monolayers (Co1/TaS2).

Main Methods:

• Synthesis of ferromagnetic single cobalt atom catalysts on TaS2 monolayers.
• Experimental and theoretical investigations of spin-polarized electronic states and OER activity.
• Tuning cobalt loading to modulate spin density of the active site.

Main Results:

• Identified a spin-polarized single cobalt atom at the hollow site (CoHS) as the active site for OER.
• Demonstrated that neighboring single cobalt sites can regulate the spin density of CoHS.
• Observed a spin density-dependent OER activity, with optimal performance achieved at a neighboring hetero-single CoTa site.

Conclusions:

• An optimal spin density of CoHS, achieved via neighboring CoTa sites, leads to superior OER performance.
• Excessive spin density from homo-single CoHS sites negatively impacts OER.
• Establishing a spin-activity correlation provides a descriptor for designing efficient magnetic SACs for renewable energy.