Experimental and Theoretical Investigations on Magneto-Electrochemical Oxygen Evolution Reaction of CoFeP Nanorods

Abstract

The pursuit of low-cost, efficient, and durable electrocatalysts for oxygen evolution in alkaline media is vital for water-splitting applications. Herein, the hydrothermal-based synthesis of a multiphase ferromagnetic catalyst CoFeP, comprising FeP, CoP, and Fe2P is reported. Structural analyses confirm the coexistence of phases, and electrochemical studies reveal excellent OER activity. CoFeP exhibits an overpotential of 335 mV at 50 mA cm−2 and a Tafel slope of 116 mV dec−1 without a magnetic field, whereas under the magnetic field of 2000 G, these values lowered to 235 mV and 93 mV dec−1, respectively. The enhancement is attributed to magnetic-field-induced spin polarization, surface reconstruction, and increased ECSA from 70 to 110 mF cm−2, highlighting the potential of magnetic modulation for boosting catalytic performance. Through spin-polarized Density Functional Theory (DFT) simulations, the structural and electronic features of CoFeP, providing theoretical insights into its role in the Oxygen Evolution Reaction (OER) is elucidated. This investigation demonstrates that the application of an external magnetic field significantly reduces the overpotential required for OER as the adsorption of intermediate species becomes stronger due to more charge transfer, aligning with experimental observations. These findings highlight the interplay between magnetic fields and electrocatalytic performance, offering a pathway to enhance energy conversion efficiency.