Magnetic field tuning of electronic structure and electrocatalytic kinetics of Fe-doped RuO2 nanofibers

Electrocatalytic water splitting is considered a crucial pathway for sustainable hydrogen production, yet its efficiency remains limited by the sluggish kinetics of the oxygen evolution reaction (OER). Compared with conventional static structural regulation strategies, the application of external physical fields offers new possibilities for dynamically tuning the electronic structure and interfacial reaction behavior of catalysts. In this work, Fe-doped RuO2 nanofibers (NFs) were prepared via electrospinning combined with calcination, and the effect of an external magnetic field on their electrocatalytic performance was investigated. The results show that an appropriate amount of Fe doping effectively modulates the local electronic environment of Ru sites, enhancing the electrical conductivity and structural stability of the material. Among them, Fe0.05Ru0.95O2 NFs exhibit the best catalytic performance. Upon further application of an 800 mT magnetic field, both hydrogen evolution reaction and OER activities are further enhanced, achieving overpotentials of 62 and 256 mV at a current density of 10 mA cm−2, respectively, and maintaining stable operation for over 200 h at 50 mA cm−2. Combined x-ray photoelectron spectroscopy, in situ Raman spectroscopy, and density functional theory analyses reveal that the magnetic field can modulate the local electronic environment of Fe–O–Ru, shifting the d-band center toward the Fermi level while lowering the energy barrier of key reaction steps, thereby improving the adsorption/desorption equilibrium of reaction intermediates.