| AVS 57th International Symposium & Exhibition | |
| Nanometer-scale Science and Technology | Thursday Sessions |
| Session NS-ThM |
| Session: | Nanowires and Nanoparticles |
| Presenter: | J. Taing, University of California, Irvine |
| Authors: | J. Taing, University of California, Irvine J.C. Hemminger, University of California, Irvine |
| Correspondent: | Click to Email |
TiO2 nanoparticles are generated on step edges of highly oriented pyrolitic graphite (HOPG) via physical vapor deposition of Ti followed by air oxidation. Deposition of Ti on HOPG while the substrate is held at 900 K results in nanoparticle growth exclusively at the graphite step edges. Since the steps on high quality HOPG are long (>1 micron) and very parallel, the result is highly ordered arrays of nanoparticles. Photodeposition of Pt on the TiO2 nanoparticles results in the decoration of the TiO2 with Pt nanoparticles (≤ 5 nm). Photodeposition of Pt is accomplished by submersion in an aqueous solution of 0.25 mM K2PtCl4 and 0.5 mM trisodium citrate followed by photolysis with TiO2 bandgap radiation (365 nm radiation from a 200 W Mercury lamp). Similarly, Ag nanoparticles can be deposited by photolysis of the sample in an aqueous solution of 0.25 mM Ag(NO)3 and 0.5 mM trisodium citrate. Scanning electron microscopy (SEM), atomic force microscopy (AFM), transmission electron microscopy (TEM), x-ray dispersive spectroscopy (EDS), and x-ray photoelectron spectroscopy (XPS) characterize the morphology, crystal structure, and chemical identity of the nanoparticles. Images of decorated TiO2 nanoparticles are included in the supplement.