Photoelectrochemical Properties of Annealed Anodic TiO Layers Covered with CuO.

In this work, we present a systematic study on the influence of Cu ion concentration in the impregnation solution on the morphology, structure, optical, semiconducting, and photoelectrochemical properties of anodic CuO-TiO materials. Studied materials were prepared by immersion in solutions with different concentrations of (CHCOO)Cu and subjected to air-annealing at 400 °C, 500 °C, or 600 °C for 2 h. The complex characterization of all studied samples was performed using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), reflectance measurements, Mott-Schottky analyses, and photocurrent measurements. It was found that band gap engineering based on coupling CuO with TiO (E~3.3 eV) is an effective strategy to increase the absorption in visible light due to band gap narrowing (CuO-TiO materials had E~2.4 eV). Although the photoactivity of CuO-TiO materials decreased in the UV range due to the deposition of CuO on the TiO surface, in the Vis range increased up to 600 nm at the same time.