Structural, Dielectric, Optical, and Electrochemical Insights into Enhanced OER Activity of Y3Fe5O12 over YFeO3 Ferrite Nanoparticles for Hydroelectric Cell Applications

YFeO 3 (YF) and Y 3 Fe 5 O 12 (YGF) nanoparticles were synthesized by a modified low-temperature sol-gel auto-combustion route to elucidate structure–property relationships governing oxygen evolution reaction (OER) and hydroelectric cell (HEC) performance. Rietveld-refined XRD confirmed orthorhombic YF and cubic garnet YGF phases, while Raman and HRTEM established phase purity, crystallinity, and morphology. YGF exhibited higher dielectric permittivity (23.20), lower dielectric loss (0.765), larger specific surface area (12.815 m 2 g − 1 ), and oxygen-vacancy-rich surface chemistry, facilitating electrochemical charge transfer. Accordingly, YGF showed higher ECSA (18.25 cm²), C dl (0.73 mF cm − 2 ), and lower Rct (359 Ω) than YF. YGF delivered superior OER activity with an overpotential of 392 mV at 10 mA cm − 2 and a Tafel slope of 133 mV dec − 1 . The YGF-based HEC achieved 14.123 mA short-circuit current, 0.981 V open-circuit voltage, and 13.854 mW maximum power, demonstrating its potential for sustainable hydroelectric energy conversion. These findings establish YGF as a promising multifunctional energy-conversion material.