Synthesis and Characterization of CuO Nanotubes (NTs) Formed By Anodization Sonoelectrochemical

The CuO is an important semiconductor material because this presents a narrow bandgap value (~1.2 – 1.7 eV), p-type conductivity, low toxicity and abundance in nature. From comparison of the photoelectrochemical behavior between CuO and others semiconductor, it is concluded that this oxide is sensible to visible radiation whereas others, more widely used such as; TiO₂, ZnO, which absorb in UV region.

Despite the above, the copper oxide has a low diffusion rate of charge carriers. Therefore, new synthesis routes leading to a nanostructured oxide is required, so that the photogenerated electrons are accumulated in the vicinity of the surface. This is to facilitate the transfer process of charge per on the recombination.

This report shows the results concerning the preparation sonoelectrochemical of CuO nanotubes (NTs). Synthesis of CuO NTs is carried out on a copper (Cu) foil in organic media (x% water in ethylene glycol + 0.5 wt % CuC₂O₄) using the electrochemical anodization method at a constant room temperature. The anodization is carried out for 10 min at an applied potential of 25 V. Cu foil acts as anode and electrode of carbon (C) acts as cathode. The anodized samples are properly washed with distilled water, to remove the occluded ions, and dried in a furnace.

The CuO NTs were characterized by sweep electronic microscopy (SEM), energy dispersive X-ray analysis (EDXA) and Raman spectroscopy.

The micrographs show an array of nanotubes on the substrate. The composition of the nanotubes immediately formed consisted mainly of copper, when the synthesis was conducted in a solution with a higher % of water. However, when the samples were heat treated in oxygen atmosphere, an array of CuO NTs was obtained.

Furthermore, these samples were characterized by Photoelectrochemical Studies.

 

Acknowledgment

The financial support of Fondecyt-Chile (Project N° 1140963) and DI-PUCV (Projects N° 037.305/2013) is gratefully acknowledged by the authors.