The spin-coupling-dependent oxygen reduction mechanism in dual-atom catalysts

Area of Science:

• Surface Chemistry
• Materials Science
• Computational Chemistry

Background:

• Spin-dependent electrocatalysis is an emerging field.
• Spin effects are understood at single sites, but spin coupling in multi-site systems is underexplored.
• Understanding spin coupling can reveal new active sites and catalytic mechanisms.

Purpose of the Study:

• To propose a general theory for understanding spin coupling in electrocatalysis.
• To investigate the impact of spin coupling on catalytic activity and mechanisms.
• To validate the theory using dual-atom catalysts (DACs).

Main Methods:

• Development of a general theory inspired by spintronics.
• Computational calculations on Fe2N6 dual-atom catalysts (DACs) with parallel spin (PS) and antiparallel spin (APS) alignments.
• Analysis of spin exchange splitting and its effect on catalyst-adsorbate bond energy.

Main Results:

• Spin exchange splitting significantly influences the oxygen reduction reaction (ORR) mechanism and activity.
• APS-Fe2N6 exhibits higher ORR activity (UL = 1.04 V vs. SHE) compared to PS-Fe2N6 (UL = 0.67 V vs. SHE).
• PS alignment enhances exchange splitting and OH/O2 adsorption; APS alignment reduces it, weakening adsorption.

Conclusions:

• The proposed theory successfully explains how spin exchange splitting alters electrocatalytic activity and mechanisms.
• Spin coupling in multi-site systems offers a new avenue for designing efficient electrocatalysts.
• This work provides significant mechanistic insights into spin-related electrocatalysis.