Platinum-Nanoparticle-Modified TiO₂ Nanowires with Enhanced Photocatalytic Property

Highly crystalline Pt nanoparticles with an average diameter of 5 nm were homogeneously modified on the surfaces of TiO(2) nanowires (Pt-TiO(2) NWs) by a simple hydrothermal and chemical reduction route. Photodegradation of methylene blue (MB) in the presence of Pt-TiO(2) NWs indicates that the photocatalytic activity of TiO(2) NWs can be greatly enhanced by Pt nanoparticle modification. The physical chemistry process and photocatalytic mechanism for Pt-TiO(2) NWs hybrids degrading MB were investigated and analyzed. The Pt attached on TiO(2) nanowires induces formation of a Schottky barrier between TiO(2) and Pt naonoparticles, leading to a fast transport of photogenerated electrons to Pt particles. Furthermore, Pt incoporation on TiO(2) surface can accelerate the transfer of electrons to dissolved oxygen molecules. Besides enhancing the electron-hole separation and charge transfer to dissolved oxygen, Pt may also serve as an effective catalyst in the oxidation of MB. However, a high Pt loading value does not mean a high photocatalytic activity. Higher content loaded Pt nanoparticles can absorb more incident photons which do not contribute to the photocatalytic efficiency. The highest photocatalytic activity for the Pt-TiO(2) nanohybrids on MB can be obtained at 1 at % Pt loading.