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 (E3.3 eV) is an effective strategy to increase the absorption in visible light due to band gap narrowing (CuO-TiO materials had E2.4 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.