Decoration of the TiO2 nanotube arays with copper suboxide by AC treatment

• We suggest the method for uniform loading of Cu2O species onto TiO2 nanotube (TiNT) walls.
• The purity of Cu2O nanocrystals tethered to TiNT walls was confirmed by numerous methods.
• TiNT films decorated with Cu2O nanocrystals possess significantly lower bang gaps.
• The mechanism of deposition from Cu(II) acetate solution by AC treatment was suggested.

Loading of semiconducting species onto the TiO2 nanotube (TiNT) film walls for more efficient photocatalysis and photovoltaic contours by one-step electrochemical deposition represents a promising strategy. Results obtained in this study demonstrated that uniform deposition of pure Cu2O nanoparticles onto the walls of TiNTs can be attained via alternating current (AC) treatment in an aqueous, slightly acidic solution containing copper and magnesium acetates. By this approach, uniform anchoring of Cu2O species into the TiNTs was obtained for as-grown and calcined films without pore clogging. The rate of Cu2O deposition was found to be dependent not only on the deposition regime but also on the TiNT pretreatment. The resulting TiNT–Cu2O heterostructures were clearly evidenced by scanning electron (SEM) and scanning transmission electron microscopy (STEM), X-ray diffraction (XRD), energy dispersive X-ray (EDX), Raman spectroscopy and voltammetric tests. UV-vis diffuse reflectance measurements were performed in order to determine the band gap energy. These measurements confirmed a significant red-shift of the absorption edge for TiNT films decorated with Cu2O species. Cu2O deposition approach presented herein is simple, cheap and allows predictable decoration or even coating of the walls of TiNT films of various thickness.

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