The effect of noble metal addition on the properties of oxide semiconductors nanoparticles

This work presents the preparation of W and V co-doped TiO2 nanoparticles (W:TiO2 and W:V:TiO2) using laser pyrolysis technique subsequently modified with noble metals Pt or Pd using chemical impregnation method. By using well defined TiO2 nanoparticles, the enhancement of catalytic activity is expected mainly due to their higher surface area and density defects relative to bulk material. Structural, morphological and optical properties of the as-obtained nanopowders have been characterized by transmission electron microscopy, X-ray diffraction, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, UV–VIS diffuse reflectance spectroscopy and photoluminescence techniques. The phase composition analysis reveals the preponderance of anatase (95%) in addition to rutile phase, its particle average size ranging from 25 to 30 ​nm. The TiO2 based nanomaterials were supplementary modified by noble metals deposition (Pt particles with dimensions of 3–4 ​nm and spherical Pd crystallites with a diameter between 3 and 9 ​nm) and their photocatalytic activity was tested in oxidative photo degradation of CH3OH, under simulated solar light. The metal modified samples displayed higher specific surface areas (3–6 times) and improved photocatalytic properties, the W:V:TiO2@Pt material showing better conversion efficiency of CH3OH to CH2O than the reference Degussa P25 sample (1.54 versus 0.90%).