Magnetic field- assisted synthesis of iron-doped cobalt oxide with abundant oxygen defects as an electrocatalyst for oxygen evolution reaction

The oxygen evolution reaction (OER) is a critical step in the overall process of water electrolysis, and developing low-cost, high-performance OER electrocatalysts is essential for achieving efficient energy conversion. In this work, iron-doped cobalt oxide was successfully prepared by a magnetic field-assisted synthesis strategy, and the material exhibited excellent catalytic performance in the oxygen evolution reaction. Specifically, the overpotential of M-Fe-Co 3 O 4 at a current density of 10 mA/cm 2 is only 297 mV, and the Tafel slope is 74 mV/dec, outperforming Fe-Co 3 O 4 synthesized under magnetic field-free conditions. By analyzing X-ray photoelectron spectroscopy, Raman spectroscopy and UV photoelectron spectroscopy , it was found that this improvement in catalytic activity mainly originated from the changes in the electronic structure of iron-doped cobalt oxide, with an increase in the content of oxygen vacancy and an increase in electrical conductivity . This work highlights the important role of magnetic fields in modulating the electronic structure of materials, demonstrates the potential of using magnetic fields to develop high-performance catalysts, and offers new possibilities for future material design and development of energy conversion technologies. • Iron-doped cobalt oxide was successfully synthesized under the magnetic field . • Magnetic field-assisted synthesis affects the electronic structure of the active center. • The richer oxygen vacancies in M-Fe-Co 3 O 4 catalyst are benefited to OER performance. • M-Fe-Co 3 O 4 exhibited outstanding OER performance with a low overpotential, and long-term durability.