Fast fabrication of nanostructured semiconducting oxides by anodic oxidation of brass

Abstract

Nanostructured semiconducting oxide layers were synthesized on the surface of alpha brass (CuZn33) by its simple one-step anodic oxidation (anodization) in a strongly alkaline electrolyte (0.1 M NaOH) at various voltages (30–60 V) followed by thermal treatment in air at 200 °C. The morphology of anodic films was studied by FE-SEM, while its composition was confirmed by EDS, XRD, and Raman spectroscopy. All anodic films exhibited a cracked morphology and were composed of particles with a size of less than 100 nm. Although the presence of Zn in the oxide layer was confirmed, especially within the deeper parts of the film, the main component was monoclinic CuO. Band gaps (Eg) of all obtained materials were also estimated from reflectance spectra, and it was found that the higher the potential applied during anodic oxidation, the wider Eg is observed. Therefore, it can be stated that such a simple electrochemical approach can be an effective way for the fabrication of visible-light-driven photocatalysts.