Electrodeposition kinetics of Ni-Mo alloy coating in choline-ethylene glycol deep eutectic system and its catalytic performance toward hydrogen evolution reaction

Abstract

The Ni-Mo alloy coatings were electrodeposited in the choline-ethylene glycol deep eutectic system(ChCl-EG) using Cu as the substrates, and the electrochemical impedance spectrum(EIS), scanning electronic microscopy(SEM), energy dispersive spectrometer(EDS) and X-ray diffraction (XRD) were employed to investigate the deposition kinetics of Ni-Mo alloy coatings. The influence of polarization potential on electrocatalytic HER performance of Ni-Mo alloy coatings was investigated. The results indicate that as the polarization potential increases, the Ni-Mo alloy coatings undergoes a process of evolution from nano Ni, Ni+MoO2 (MoO2Ni4) to Ni4Mo, indicating that potential is an important factor affecting the component change of Ni-Mo alloy coatings. Ni-Mo alloy coating fabricated at -1.4 V vs Ag displays excellent hydrogen evolution catalytic activity and stability, where the overpotential at 10 mA·cm-2 is only 51 mV, the Tafel slope is 48.7 mV·dec-1, and the decrease in hydrogen evolution overpotential is not significant(Δη100=11 mV) at 100 mA·cm-2 after 1000 cycles of catalytic cycling.

Keywords

• chcl-eg deep eutectic solvent
• ni-mo alloy coating
• deposition kinetics
• electro catalysis
• hydrogen evolution reaction(her)