Ball-flower-shaped Ni nanoparticles on Cu modified TiO2 nanotube arrays for electrocatalytic oxidation of methanol

• Highly ordered TiO2 nanotube array modified with copper was used as a substrate.
• Nickel nanoparticles were deposited on the nanostructured titanium layer by two-step electrodepositon.
• The nickel nanoparticles showed a ball-flower structure and gave large specific area.
• This electrode showed remarkably enhanced activity and good stability toward methanol oxidation.

A facile method to prepare nanostructured electrode with high efficiency for methanol oxidation is represented in this study, in which highly ordered TiO2 nanotube arrays modified with copper was employed as a substrate, and nickel nanopartilces were subsequently deposited on the substrate by two-step electrodeposition. The nickel nanoparticles possess a ball-flower structure, leading to a large specific surface area. In addition, the copper interlayer enhanced the conductivity of substrate and showed a synergistic effect with Ni, which enhanced the rate of electron transfer process. Compared with other nickel electrodes, this electrode exhibited much higher electrocatalytic properties toward the methanol electrooxidation, the peak current density reached 510 mA cm−2 and the peak potential shifted negatively.