Morphology, electron structure, and catalytic activity in CO oxidation over a Au/FeO x /SiO2/Si(100) model sample prepared by pulsed laser deposition (PLD) have been investigated by X-ray photoelectron spectroscopy (XPS), UV photoelectron spectroscopy (UPS), and transmission electron microscopy (TEM). Two types of sample were prepared denoted by PLD I and PLD II, the latter being prepared by multiple laser deposition alternatively by iron and gold. PLD I was characterized in “as prepared” oxidized and reduced states, the respective gold particle sizes being 3.8, 4.1, and 5 nm; the iron oxide support was amorphous after the first two treatments while it was partially crystallized after reduction. The activity in CO oxidation increased after oxidation of the sample, whereas it was diminished after subsequent reduction. XPS studies showed that higher activity was associated with amorphous iron oxide with Fe 2p binding energy = 711.3 eV. It was established that in developing the catalytic activity the gold should be metallic and the support should be amorphous with high binding energy and the reaction occurs at the perimeter of gold particles. PLD II has a slightly lower activity which might be the result of more crystalline phase in the iron oxide.

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The surface morphology of machined screw-shaped titanium dental implants was modified by pulsed irradiation with an Nd glass laser. This method supplied very different surface elements in nanometer and micrometer ranges identified with scanning electron microscopy and atomic force microscopy as well. The surface composition was unchanged during these treatments. A rabbit experiment was carried out to investigate the direct bone contact (osseointegration) which was characterized by the removal torque of the implants. The 50 nm and 10-50 µm sized droplike elements were formed from the machined flat surface by the laser irradiation depending on the laser intensity. The osseointegration was enhanced by the increase of the density of nanosized elements and by the size of the microsized elements, showing the importance of this surface morphology in the direct bone-implant contact.

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Copper thin films consisting of nanosized particles were deposited on a Si(100) single-crystal substrate by laser ablation in an argon atmosphere. In order to obtain isolated particles with nanometer sizes, the film was sputtered by low-energy Ar + ions. The valence band density of states of the film was in situ investigated by X-ray and ultraviolet photoelectron spectroscopies (XPS and UPS) during the Ar + ion sputtering. The size of the particles formed after sputtering was in the range between 3 and 6 nm in lateral dimension and 2-3 nm in height, as measured by transmission electron microscopy. In the as-deposited state the photoelectron spectrum of the thin layer was identical to what was observed in the bulk. At the end of thinning by Ar + ion sputtering the 3d valence states were rehybridized with respect to the bulk states, which indicates that the lower binding energy part of the d band (around 2.5 eV) is the most sensitive for size reduction. The Fermi edge became undetectable by photoemission. These data show that the valence band of small particles are affected by both the size and geometry of the particles. Supporting experiments showed that the effect is attributed to neither copper silicide formation nor intermixing.

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