Prickly Nickel Nanowires Grown on Cu-Ni Substrate Surface as High Performance Cathodes for Hydrogen Evolution Reaction

A new and highly rough nickel electrode is fabricated based on in-situ assembling of prickly nickel nanowires, synthesized by electroless deposition method on a layer of nickel freshly preelectrodeposited on copper, constructing Cu-Ni-PNNWs. Then, the fabricated electrode is studied for Hydrogen Evolution Reaction (HER). Surface morphology of the electrodes is characterized by Field Emission Scanning Electron Microscopy (FESEM) and X-ray diffraction (XRD) microanalysis. Kinetics of the HER is studied in 0.5 M H2SO4 on Cu-Ni-PNNWs electrode in comparison with Ni and Cu-Ni electrodes. Evaluation of the electrode activities is carried out by steady-state polarization curves (Tafel plots) and electrochemical impedance spectroscopy (EIS). The results obtained by electrochemical characterizations have shown that the Cu-Ni-PNNWs electrode benefits of high electrocatalytic activity for the HER. The EIS data are approximated using appropriate equivalent circuit model, and values of the model parameters are extracted. Analysis of the EIS results has revealed that the double layer capacitance (Cdl) and exchange current density (j0) of the Cu-Ni-PNNWs electrode are increased by factors of ~ 47 and ~ 19 times, respectively, compared with Cu-Ni. Up to our knowledge, this is the first finding of this type, reporting synthesis and activity of the Cu-Ni-PNNWs electrode for the HER.