Résumé:
The development of electrocatalysts with enhanced reactivity, stability, and costeffectiveness is a critical challenge in advancing sustainable energy systems. Large-scale
applications such as hydrogen production and fuel cells often rely on expensive precious metals
to ensure performance and durability. Designing efficient and affordable electrodes for both the
hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) is essential for
improving the viability of hydrogen energy technologies. The development of highperformance electrocatalysts for overall water splitting and fuel cell processes remains a
significant hurdle in this field.
This study investigated nonprecious metal-based electrodes, including Ni, Ni-Mn, Ni-MnCo, and Ni-Mn-Co-Fe thin films, as electrocatalysts for the HER, OER, and overall water
splitting. The electrodes were synthesized via electrochemical deposition and characterized by
scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray diffraction
(XRD) to analyze their morphology, surface roughness, and phase structure. The
electrocatalytic performance of these materials was evaluated through linear sweep
voltammetry (LSV) and electrochemical impedance spectroscopy (EIS) under alkaline
conditions.
The Ni-Mn-Co-Fe electrode demonstrated outstanding catalytic activity, requiring
overpotentials of 436 mV for the HER and 447 mV for the OER to achieve a current density of
100 mA/cm². This performance is attributed to its unique microstructure, enhanced
electrochemically active surface area, and synergistic interaction with its components. The
electrode also exhibited excellent stability, with a less than 4% increase in overpotential after
20 hours of continuous electrolysis at 100 mA/cm². As a bifunctional electrode in watersplitting systems, it achieves a current density of 10 mA/cm² at a cell voltage of 1.57 V vs.
RHE, highlighting its potential for practical applications.
Key deposition parameters, including the bath composition, scan rate, pH, current density,
applied potential, deposition time, supporting electrolyte, and temperature, were systematically
optimized for the Ni, Ni-Mn, and Ni-Mn-Co-Fe films. The electrocatalytic performance was
assessed in alkaline KOH solutions at various temperatures and concentrations. Comparative
analysis of the deposition conditions, including scan rates (5–50 mV/s), pH values (1.5–7.5),
V
bath temperatures (25°C–60°C), and applied potentials (-0.5 to -1.4 V vs. Ag/AgCl), enabled a
comprehensive understanding of the factors affecting catalytic efficiency.
This study presents an effective strategy for producing active, stable, and cost-efficient
electrocatalysts, demonstrating a scalable approach for renewable energy applications. These
findings contribute to the development of high-performance catalysts for sustainable hydrogen
production and fuel cell technologies
