Catalysis of Gold Nanoparticles Deposited on Metal Oxides

Zinc oxide(ZnO) nanostructures with controlled morphology have been synthesized by a facile sonochemical method using cetyl trimethyl ammoniumbromide (cationicsurfactant) as a structure  directing agent.The influence of surfactant concentration on the evolution of morphology,from starlet-
like 3D structures to 2D flakes, has been systematically investigated.Room temperature formation of phase-pure ZnO crystals has been confirmed by X-ray diffraction (XRD).Field emission scanning electron microscopy (FESEM) reveals the dimensions of ZnO flakes, which are 200–400 nm wide and a few nanometre thick.Molecular fingerprints of the synthesized materials have been obtained by Fourier transform infrared spectroscopy (FTIR), while UV–vis spectroscopy estimates the band gap of ZnO as 3.37eV.

The strong interaction between Pt and TiO2 under oxidizing atmosphere was studied by means of X-ray photoelectron spectroscopy (XPS) and Ar+ sputtering test. The results obtained show that under oxidizing atmosphere Pt0 atoms can thermally diffuse into TiO2 lattice and be oxidized to Pt2+ to substitute for Ti4+ or form the interstitial ions at 673 K.