Nanostructured Pt-TiO2 composite thin films obtained by direct liquid injection metal organic chemical vapor deposition: Control of chemical state by X-ray photoelectron spectroscopy

Nanostructured Pt-TiO2 composite thin films were synthesized by direct liquid injection metal organic chemical vapor deposition process, using trimethyl(methylcyclopentadienyl)platinum and titanium isopropoxide as precursors. Surface and cross-sectional morphologies obtained by scanning electron microscopy and transmission electron microscopy evidenced the uniform distribution of platinum nanoparticles in the TiO2 matrix. At higher Pt content, the X-ray diffraction analysis showed that the face-centered cubic phase of platinum appeared together with an anatase TiO2 structure. In addition, as far as the platinum chemical state is concerned, the co-deposition of TiO2 and Pt allowed obtaining Pt2 + or Pt°, in a ratio strongly dependent on the Pt content. Indeed, X-ray photoelectron spectroscopy characterization evidenced the presence of only Pt2 + for lower Pt content and only Pt° for higher one. The variation of platinum content in the TiO2 films resulted in a change of the chemical state of platinum.