A Versatile C/Fe₃O₄/C Self‐Heating Electrode for Universal Application of Alternating Magnetic Fields in Electrocatalytic Hydrogen Production

Abstract The high‐frequency alternating magnetic field (AMF) is considered as a fascinating heating treatment that provides a noninvasive solution to enhance the catalytic efficiency of electrocatalyst. However, practical applications of AMF in electrochemistry are primarily concentrated on magnetic mediums. To broaden its application into nonmagnetic catalysts, herein, a practicable method is reported by modifying the working electrode substrate with magnetic Fe₃O₄ nanoparticles (NPs), which serves as both substrate and self‐heating medium by virtue of its rapid and efficient magnetic heating effect associated with Néel relaxation triggered by external high‐frequency AMF, thus boosting the catalyst performance upon it. To verify it, Pt NPs and Pt single atoms (SAs), as two representative non‐magnetic catalyst, are selected for trials. The results, reveal that, when AMF is applied, Pt NPs@C/Fe₃O₄/C and Pt SAs@C/Fe₃O₄/C display remarkable enhancement of hydrogen evolution reaction magnetocurrent density respectively by ≈ 146% and ≈185%, whereas on unmodified bare glassy carbon there both show unnoticeable change in catalytic performance. The developed strategy opens up a vast space for exploiting the energy of a weak, non‐invasive magnetic field.