Ferromagnetic transformation of α-Fe2O3via Co doping for efficient water oxidation under magnetic field

Abstract

The introduction of a magnetic field has great potential for enhancing oxygen evolution reaction (OER) performance, but it requires the catalyst to be ferromagnetic and there is a lack of understanding of the fundamental mechanisms. Herein, we achieved the transformation of non-ferromagnetic α-Fe₂O₃ into ferromagnetic Co_0.14FeO_x by Co doping. Compared to α-Fe₂O₃, the OER activity of Co_0.14FeO_x considerably increased under a magnetic field of 3000 Oe and is proportional to the magnetic field strength within a certain range. This can be ascribed to the external magnetic field enhancing the degree of the magnetic moment ordering of Co_0.14FeO_x, which improved electron spin polarization.