Hydrogen, as a clean an‎d renewable fuel, plays an important role in the transition from fossil fuels to green an‎d sustainable energy systems. Therefore, the development of stable an‎d low-cost electrocatalysts for large-scale green hydrogen production is of great importance. In this research, a green an‎d environmentally friendly synthesis route is introduced for the preparation of mono-metallic, bi-metallic, an‎d tri-metallic oxides electrocatalysts based on cobalt (,), copper(), an‎d nickel ()—metals that are inexpensive an‎d abundant. In this method, two types of deep eutectic solvents, including choline chloride–urea an‎d glycolic acid–betaine, with specific molar ratios, were used. In the first step, the metal salt precursors were ground together with sodium oxalate an‎d added to the deep eutectic solvent. After complex formation, the mixture was subjected to a two-step calcination process. In the next step, the calcined samples were characterized using FT-IR, FE-SEM, TEM, an‎d XRD analyses. Then, 18 electrocatalysts were synthesized under the mentioned conditions, an‎d their electrocatalytic performance in 0.1 an‎d 0.5 M sulfuric acid electrolyte, an‎d 1 an‎d 3 M potassium hydroxide electrolyte, for hydrogen an‎d oxygen evolution reactions, was carefully investigated an‎d the results were fully reported. According to the results of electrochemical tests, the bi-metallic cobalt–copper oxide electrocatalyst with an equal molar ratio showed the best performance in the hydrogen evolution reaction in an alkaline medium, with an overpotential of −257 mV an‎d a Tafel slope of 64 mV·dec⁻¹. Finally, the results revealed that the morphology, impurities, an‎d the type of metal used all simultaneously play a fundamental role in the electrochemical activity of the samples.

حسن حداد زاده

اسماعيل حيدري

كاظم كرمي , محسن مومني