Heterointerface-mediated magnetic proximity accelerates oxygen evolution

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Electrochemical water splitting is crucial for clean energy, but the oxygen evolution reaction (OER) is kinetically limited and spin-dependent.
• External magnetic fields can enhance OER by modulating spin selectivity but pose safety risks and introduce non-spin effects.
• A need exists for magnetic field-free strategies to improve OER catalyst performance.

Purpose of the Study:

• To develop an external magnetic field-free strategy for enhancing oxygen evolution reaction (OER) performance.
• To investigate the application of the magnetic proximity effect (MPE) in designing efficient OER electrocatalysts.
• To create a novel ferromagnetic core-shell catalyst for improved OER kinetics.

Main Methods:

• Fabrication of Fe7S8@WS2 core-shell nanostructures using electrospinning and chemical vapor deposition.
• Electrochemical characterization of the Fe7S8@WS2 catalyst for alkaline OER.
• Experimental and theoretical studies (including DFT) to elucidate the mechanism of MPE-induced spin polarization.

Main Results:

• The Fe7S8@WS2 catalyst achieved a low overpotential of 222 ± 13 mV at 50 mA cm⁻² for alkaline OER.
• Demonstrated that the ferromagnetic Fe7S8 core induces proximity spin polarization in the WS2 shell via interfacial exchange coupling.
• Showed that MPE-driven spin regulation optimizes the electronic structure of WS2, lowering the OOH formation barrier and enhancing OER kinetics.

Conclusions:

• The magnetic proximity effect (MPE) provides an effective external field-free strategy for designing advanced OER electrocatalysts.
• The Fe7S8@WS2 core-shell structure serves as an efficient internal magnetic source, promoting spin-selective OER.
• This work offers a new pathway for developing safer and high-performance ferromagnetic electrocatalysts for water splitting.