| AVS 59th Annual International Symposium and Exhibition | |
| Surface Science | Tuesday Sessions |
| Session SS+NS-TuA |
| Session: | Reactivity of Size and Shape Selected Nanoparticles |
| Presenter: | J. Taing, University of California Irvine |
| Authors: | J. Taing, University of California Irvine A. Margarella, University of California Irvine Y. Liu, University of California Irvine J.C. Hemminger, University of California Irvine |
| Correspondent: | Click to Email |
TiO2 nanoparticles were decorated onto the step edges of highly oriented pyrolytic graphite (HOPG) via physical vapor deposition. Gold shells and nanoparticles were then grown on the TiO2 nanoparticles using a photoelectrochemical cell whereupon a photocatalytic reduction mechanism is verified by photocurrent measurements. Samples of TiO2 nanoparticles on HOPG, acting as a photoelectrode, were placed in a half-cell and immersed in either an electrolyte solution of 1.0 M NaCl or 1.0 M NaNO3. Bare HOPG, acting as a counter electrode, was placed in a second half-cell and immersed in the same electrolyte solution. The two half-cells were connected by a salt bridge and the electrodes by a picoammeter. Upon irradiation of the TiO2 nanoparticles by 365 nm UV light from a 200 W Hg lamp, photogenerated electrons produced a photocurrent. Subsequent to introducing 1 mL of 15 μM HAuCl4 into the cell containing the TiO2 nanoparticles, the photocurrent decreased as a result of the reduction of Au3+ to Au on TiO2. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), x-ray dispersive spectroscopy (EDS), and x-ray photoelectron spectroscopy (XPS) were used to characterize the morphology, crystal structure, and chemical identity of the nanoparticles. Images of TiO2 nanoparticles encapsulated in Au are included in the supplement.