Chirality-Magnetism Coupling for Spin-Catalytic Oxygen Evolution.

Area of Science:

• Materials Science
• Catalysis
• Physical Chemistry

Background:

• Spin-mediated promotion is a key strategy to overcome spin conservation limitations in the oxygen evolution reaction (OER).
• Magnetic fields are effective for OER but have limited impact on weak-magnetic-susceptibility electrocatalysts.
• Developing new strategies to enhance OER activity is crucial for efficient water splitting.

Purpose of the Study:

• To impart structural chirality into an antiferromagnetic electrocatalyst (NiO) to improve OER activity.
• To investigate the cooperative effect of chiral structure and external magnetic fields on electron spin polarization.
• To establish a new paradigm for spin-dependent catalysis using chirality-magnetism coupling.

Main Methods:

• Lattice distortions were used to introduce structural chirality into NiO.
• Theoretical calculations and experimental results were employed to study electron spin polarization.
• Electrochemical measurements were performed to evaluate OER activity under varying magnetic field conditions.

Main Results:

• Chiral NiO exhibited exceptional sensitivity of electron spin polarization to external magnetic fields, with direction-dependent effects.
• Optimal magnetic field orientations for L-NiO and D-NiO maximized spin-polarized electron transfer and facilitated spin-exchange coupling.
• L-NiO and D-NiO under optimal magnetic fields showed 7.5- and 6.2-fold higher current densities, respectively, compared to achiral NiO.

Conclusions:

• Chirality-magnetism coupling effectively induces electron spin polarization in antiferromagnetic electrocatalysts, significantly enhancing OER activity.
• This approach broadens the applicability of magnetic fields in boosting OER and offers a new route for highly efficient spin-dependent catalysis.
• The findings present a novel paradigm for designing advanced electrocatalysts by integrating chirality and magnetism.