The surface science of titanium dioxide

http://www.licn.phys.soton.ac.uk/restricted/Catalytic%20activity%20of%20Au%20nanoparticles-Lecture%201.pdf

Catalytic activity of Au nanoparticles

/pdf/surface-chemistry-of-catalysis-by-gold-37hj5cal3q.pdf

Surface chemistry of catalysis by gold

Probing surface and interface morphology with Grazing Incidence Small Angle X-Ray Scattering

Interaction of nanostructured metal overlayers with oxide surfaces

Scanning tunneling microscopy studies of metal clusters supported on TiO2 (110): Morphology and electronic structure

The growth and interaction of Ag with the TiO2(110) (1 × 1) and (1 × 2) surfaces were studied by X-ray photoemission spectroscopy (XPS), low-energy ion scattering (LEIS), low-energy electron diffraction (LEED), and scanning tunneling microscopy (STM). At 300 K, both LEIS and STM data indicate that Ag grows three-dimensionally on the (1 × 1) and (1 × 2) surfaces; no strong chemical interaction between Ag and TiO2 was detected by XPS. At 0.05 ML Ag exposure (corresponding to a cluster diameter of 2.0−3.5 nm), the Ag 3d core level binding energy shifts to 1.2 eV higher than that for metallic (bulk) Ag. In addition, the Ag 3d peak width increases with decreasing cluster size. The binding energy shifts and peak broadening are attributed to both initial and final state effects. The valence band as a function of Ag exposure suggests that a metal-to-nonmetal transition occurs within the Ag clusters at exposures between 0.5 and 1 ML (3.5−4.4 nm). No change in the cluster growth mode was observed upon Ag deposition...

Silver Growth on TiO2(110) (1 × 1) and (1 × 2)†

The interaction of ultrathin Cu films with Pd(111) was studied by X-ray photoelectron spectroscopy (XPS). The effects of Cu coverage and annealing temperature were investigated. The XPS data show that at room temperature Cu grows on Pd(111) layer-by-layer without alloying. Furthermore, Cu 2p3/2 core-level shifts as a function of film thickness indicate that the Cu−Pd interactions perturb the electronic properties of two to three layers of Cu atoms. The Cu 2p3/2 binding energy of a Cu monolayer at room temperature was shifted by −0.47 eV relative to a Cu(100) surface. XPS core-level shifts demonstrate that by annealing to temperatures higher than 450 K the Cu overlayer alloys with the Pd substrate. After annealing to 900 K, the Cu 2p3/2 binding energy for 1.0 ML Cu coverage was observed to shift −0.49 eV relative to that of 1 ML Cu/Pd(111). The XPS binding energy shifts are discussed in terms of both initial and final state effects.

An XPS Study of the Interaction of Ultrathin Cu Films with Pd(111)

Ultrathin metal films (UTMFs) are used in a wide range of applications, from transparent electrodes to infrared mirrors and metasurfaces. Due to their small thickness (<5 nm), the electrical and optical properties of UTMFs can be changed by external stimuli, for example, by applying an electric field through an ion gel. It is also known that oxidized thin films and nanostructures of Au can be reduced by irradiating with short-wavelength light. Here we show that the resistance, reflectance, and resonant optical response of Au UTMFs is changed significantly by ultraviolet light. More specifically, photoreduction and oxidation processes can be sequentially applied for continuous tuning, with observed modulation ranges for sheet resistance (Rs) and reflectance of more than 40% and 30%, respectively. The proposed method has the potential for achieving reconfigurable UTMF structures and trimming their response to specific working points, e.g., a predetermined resonance wavelength and amplitude. This is also important for large scale deployment of such surfaces as one can compensate material nonuniformity, morphological, and structural dimension errors occurring during fabrication.

T.P. St. Clair

Papers

Scanning tunneling microscopy studies of metal clusters supported on TiO2 (110): Morphology and electronic structure

Silver Growth on TiO2(110) (1 × 1) and (1 × 2)†

An XPS Study of the Interaction of Ultrathin Cu Films with Pd(111)

Tuning of Ultra-Thin Gold Films by Photoreduction