Influence of Crystal Modifier Content on Ni-Cu Catalysts Dedicated to the Hydrogen Evolution Reaction

Ammonium chloride is a commonly used crystal modifier allowing the production of conical structures. Metals and alloys synthesized in the form of cones show enhanced catalytic activity and active surface area. Ni-Cu alloys as candidates for catalysts in the hydrogen evolution reaction were synthesized using a one-step method. The influence of the NH₄Cl content on morphology, chemical and physical composition, wettability, roughness, and catalytic properties was analyzed using many techniques, including, inter alia, Scanning Electron Microscopy, X-ray Diffraction, Atomic Force Microscopy, and Linear Sweep Voltammetry. The proposed deposition parameters allow the successful synthesis of conical Ni-Cu structures with promising catalytic activity compared with other coatings of these alloys. The lowest determined value of the Tafel slope is 79 mV/dec for the sample deposited from the electrolyte with 40 g/L NH₄Cl.