Dispersion of nanosized noble metals in TiO2 matrix and their photoelectrode properties

The M/TiO2 (M=Pt, Au) nanocomposite thin films were deposited on quartz and indium tin oxide (ITO) glass substrates using a co-sputtering method. TiO2 in rutile form is the dominant crystalline phase for as-deposited nanocomposite films. Along with heat treatment up to 600 °C, X-ray diffraction (XRD) peaks of the rutile phase as well as those of noble metal increased in intensity and decreased in width, indicating the growth of crystallites. X-ray photoelectron spectroscopy (XPS) revealed that Au and Pt existed as metallic phases in the TiO2 matrix. The anodic photocurrents of M/TiO2 (M=Au, Pt) thin films were observed not only in the ultraviolet (UV) range but also in the visible light range. This is due to the dispersion of nanosized noble metal in the TiO2 matrix.