Preparation of Nanostructured FeCoNiMgO_x Medium-Entropy Oxides by Using a Milk Template for Efficiently Promoting...

Development of medium-entropy oxides (MEOs) with highly efficient and durable electrocatalytic properties is a crucial topic in the electrolysis field because of their widely tunable composition and lattice distortion effects. However, it is still a challenge to fine-adjust the crystal structure of MEOs in nanoscale. In this study, an innovative and low-cost route is demonstrated to fabricate a medium-entropy oxide/carbon (FeCoNiMgO_x/C) electrocatalyst by using a milk template, which endow it with a nanoparticle microstructure and O vacancy rich spinel crystal. Herein, the milk-based template is essential for constructing the nanostructure and incorporating oxygen vacancies into the FeCoNiMgO_x medium-entropy oxide, thereby boosting its intrinsic catalytic activity toward the oxygen evolution reaction (OER). The derived catalyst exhibits a Tafel slope of 95.0 mV dec^-1 and achieves a low overpotential of 250 mV at a current density of 10 mA cm^-2 during the OER. This research demonstrates a sustainable bioinspired templating strategy for developing robust and efficient OER electrocatalysts, offering potential for economical hydrogen production via water electrolysis.