The role of FexCu(1‒x) electrodeposits from a deep eutectic solvent in promoting the hydrogen evolution reaction

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Hydrogen from water splitting is more powerful, clean, and more energy-efficient than fossil fuels. Since the electrode material influences the performance and operating cost of industrial electrolyzers, this work induces technological innovation through FexCu(1−x) alloys with electrocatalytic action toward the hydrogen evolution reaction (HER). The materials were galvanostatically deposited on 1020 carbon steel. It was used electrolytes formulated with deep eutectic solvents (DES) and aqueous solvents (AQS) were used to verify their influence on the coatings' composition, morphology, and electrocatalytic activity. The results proved that even after fixing the operating conditions (electrochemical potential, current density, and deposition time), the alloys produced in DES are richer in Fe (≅ 77-85%, w/w). For comparison, those obtained from AQS have greater proportion of Cu (≅ 65%, w/w). Stoichiometry changes also alter the topography, surface area, and electrocatalytic activity of FexCu(1−x) alloys for hydrogen production. The electrochemical studies carried out also revealed that the association between Fe and Cu as alloying elements has a positive synergistic effect of reducing the HER overpotential by around 125 mV, using 1 mol L−1 KOH at 296 K. Considering stability and resistance to corrosion, FexCu(1−x) alloys produced in DES stood out as the most promising for possible adaptation in electrolyzers developed for large-scale hydrogen production.