Raman spectroscopy of nanograins, nanosheets and nanorods of copper oxides obtained by anodization technique.

Different nanostructures such as: CuOH nanorods, CuO nanosheets and Cu2O nanograins were obtained by anodization approach at room temperature during times from 10 to 40 minutes. By scanning electron microscopy technique, it was found that Cu2O nanograins were formed at 10 minutes, CuO nanosheets vertically oriented on nanograins were observed at 20 and 30 minutes, and from 20 minutes CuOH nanorods with low vertical orientation on nanosheets were formed, coexisting the three types of nanostructures at the same system. In samples without thermal treatment were observed that Raman spectra of nanograins have a typical signal at 218 cm-1 associated to Cu2O, Raman spectra of nanosheets have signals at 287 and 630 cm-1 associated to CuO and Raman spectra of nanorods, it was observed that Raman spectrum is dominated by an intense signal associated to CuOH located around 488cm-1. In addition, after 3 hours of thermal treatment at 300 °C, the morphology was conserved, and the hydrogen-related compound decreased. Raman spectra of nanorods only presented a signal at 287 cm-1 associated to CuO whereas in nanosheets three peaks at 150, 218, 304 cm-1 associated to the Cu2O were observed.