Magneto-Electrocatalysis of Co-Ni Alloy Electrodeposits for Hydrogen Evolution Reactions

Abstract

Abstract Co–Ni alloy with various compositions were fabricated through a one-step electrodeposition process and evaluated as electrocatalysts for the hydrogen evolution reaction (HER). The electrocatalytic behaviour of the deposited alloys were systematically investigated under both conventional electrocatalytic and magneto-electrocatalytic (0.3 T magnetic field strength) conditions. The Co–Ni alloy exhibited excellent HER activity, which was further enhanced upon the application of an external magnetic field. The magnetic field significantly improves the electron-transfer kinetics, reducing the HER overpotential from 141 mV to 114 mV and increasing the current density from 511 to 533 mA.cm-2. Electrochemical impedance spectroscopy (EIS) further confirmed the magnetic-field-induced enhancement by showing a decrease in charge-transfer resistance (Rct) from 30.5 Ω.cm-2 to 17.1 Ω.cm-2. Field-emission scanning electron microscopy (FESEM) revealed composition-dependent surface morphologies, transitioning from micro-conical and rough architectures in Co-rich alloys to smoother surfaces in Ni-rich compositions. X-ray photoelectron spectroscopy (XPS) provided insights into the surface chemistry, demonstrating composition-dependent shifts in Co and Ni binding energies. This study highlights the effectiveness of magneto-electrocatalysis in boosting the HER performance of electrodeposited Co–Ni alloys and emphasizes the potential of integrating external magnetic fields to achieve superior electrocatalytic activities.

The authors' abstract, as published at the source. Journal of The Electrochemical Society, 2026 · DOI ↗