Surface modification of Ni foam by the dendrite Ni-Cu electrode for hydrogen evolution reaction in an alkaline solution

Abstract

Hydrogen is a renewable energy source that is considered among the candidate alternatives to fossil fuels. In this research, dendrite NiCu coating is the electrodeposited and catalytic performance of this electrode is investigated toward hydrogen evolution reaction (HER) in 1.0 M KOH. The response surface methodology (RSM) as the design of experimental (DOE) method is used for optimizing the intrinsic electrocatalytic HER activity (NiCu A) and active surface area (NiCu B) of the dendrite NiCu coating. The DOE results showed that the active surface area had a stronger effect on the electrocatalyst HER activity than the intrinsic parameter. The η10 (overpotential at 10 mA cm−2) and Tafel slope of the NiCu B electrode were 202 mV vs. RHE and 82 mV dec−1, respectively. According to the Tafel slope of the optimized NiCu B electrode, the Volmer-Heyrovsky mechanism predominated the HER mechanism. The NiCu B electrode showed high electrocatalytic activity and electrochemical stability compared to recently proposed catalysts. The electrocatalyst stability of the NiCu B electrode led to the small size of the H2 bubble on the surface of the electrode. The low size and rapid detachment of the H2 gas bubbles resulted in the dendrite NiCu B structure.