Thermal-stimulated spin disordering accelerates water electrolysis†

Abstract

The sluggish kinetics of the oxygen evolution reaction (OER) greatly limits the efficiency of water splitting. High OER overpotentials would originate from high electron transfer barriers in electrolyte/catalytic layer/catalyst core interfaces during water oxidation reactions. Herein, we assembled a temperature-dependent magnetic YFe_1−xMn_xO₃ core and paramagnetic YFeOOH shell to form a YFe_1−xMn_xO₃@YFeOOH core–shell structured catalyst to explore the effects of the thermal-stimulated magnetic state of catalytic materials on OER kinetics. We found that the thermal-stimulated paramagnetic state of the YFe_1−xMn_xO₃ core contributes to accelerated electron transfer at the YFe_1−xMn_xO₃@YFeOOH core-catalytic layer interface. Meanwhile, it improves the intrinsic OER activities of the YFeOOH catalytic layer. The thermal-stimulated magnetic transition of YFe_1−xMn_xO₃ (from antiferromagnetic to paramagnetic) increases the magnetic disorder at the YFe_1−xMn_xO₃@YFeOOH interface to reduce spin-flipping barriers and induces the production of highly OER-active electronic states for the YFeOOH catalytic layer owing to the strong interactions between the YFe_1−xMn_xO₃ core and YFeOOH catalytic layer, thus breaking the linear Arrhenius relationship. Our findings provide a new low-barrier OER route via thermal-stimulated magnetic disordering.