Cu Electro-Redox on the Surface of Single-Walled Carbon Nanotube Network

In this study, pristine single-walled carbon nanotube (SWNT) networks were used as the templates for the copper nanoparticle electrodeposition and the electro-redox process were investigated. The working electrode, SWNT networks, was prepared via catalyzed chemical vapor deposition on insulating SiO₂ surface and was characterized by scanning electron microscopy, thermogravimetric analysis, transmission electron microscopy, X-ray photoelectron spectroscopy, and linear sweep analysis. In the static experiment (batch reactor), deposition of high-density Cu nanoparticles on the SWNTs was observed via atomic force microscopy and field emission scanning electron microscopy, over extensive periods (45s), with contiguous formation from the boundary to further distances. Mass transfer was quantitatively analyzed via chronoamperometry and normal pulse voltammetry and physical adsorption of the copper ions were observed to demonstrate a positive temperature-dependence. A range of Cu ion concentrations was used to analyzed the electron transfer till the mass transfer and adsorption processed were saturated and the electron transfer rates were determined to be 1.5×10¹⁷ and 2.6×10¹⁸e^-s^-1m^-2 at anode potentials of 0.3 and 0.5V,repectively. All these above approaches described the nucleation and growth processes of Cu nanoparticles on SWNTs during electrodeposition. In comparison with Ag and Pt growth reported before, Cu nanoparticles grew less rapidly and progressively. The dynamic experiment (filter reactor) is on-going based on results of the static one. Our work is promising to provide a new route to recover copper from waste mining water.