With the aim of addressing the material gap issue between model and real systems in heterogeneous catalysis, we exploited Pulsed Laser Deposition (PLD) to produce Pd clusters supported on ultrathin alumina films (Pd/Al2O3/NiAl(001) and Pd/Al2O3-x/HOPG). The structural properties have been investigated by in situ Scanning Tunneling Microscopy (STM) in ultra high vacuum (UHV). At first, Pd clusters were deposited by evaporation and by PLD on Al2O3 surfaces grown by thermal oxidation of NiAl(001). The system shows thermal stability up to 650 K. By PLD we deposited Pd clusters with a good size control obtained by varying the background gas pressure and the target-to-substrate distance. We then realized a

Pd/Al2O3-x/HOPG system where both Pd clusters and the alumina film are produced by PLD showing that, by exploiting the same deposition technique, it is possible to synthesize both a model system addressable by in situ STM and a thick film (∼100 μm) closer to realistic systems.

Colloidal Au/Ag nanoparticles can be controllably assembled on anodic aluminum oxide (AAO) surfaces; monolayer coating on the membrane on AAO with smaller pores, or a nano-net arrangement along the edges of AAO with larger pores. The supported Au and Ag nanoparticles on the AAO membranes are closely packed and exhibited localized surface plasmon resonance (LSPR). Thus AAO membrane coated with Au or Ag nanoparticles is a highly surface-enhanced Raman scattering (SERS) active substrate. High quality SERS spectra were obtained using fullerene molecules C60 & C70 as the probe molecules and the filtered Au nanoparticles as the substrate. Furthermore, new SERS systems were obtained from Au nanoparticles assembled into the pores of AAO-supported fullerene nano-tubes, and the C60/C70 nano-tube arrays loaded with Au nanoparticles. The new SERS systems made use of the contributions from AAO, the LSPR of the Au nanoparticles, and a uniform assembly of the probe molecules in the nanostructures. These approaches have also been applied to small organic molecule systems using Ag nanoparticles.

The rational design of new heterogeneous catalysts for clean chemical technologies can be accelerated by molecular level insight into surface chemical processes. In-situ methodologies, able to provide time-resolved and/or pressure dependent information on the evolution of reacting adsorbed layers over catalytically relevant surfaces, are therefore of especial interest. Here we discuss the application of in-situ XPS and in-situ, synchronous DRIFTS/MS/XAS methodologies to elucidate the active site in Pd-catalyzed, selective aerobic oxidation of allylic alcohols.

Al2O3 films (2-5nm) deposited on SiO2/Si (100) n-type substrate with thickness 500μm were characterized by Synchrotron Radiation- X-ray Photoelectron Spectroscopy (SR-XPS). Excitation energy 730eV show surface sensitive results compare to 1000eV. Using excitation energy 730eV, Al, Si, O core-level elements and their excited species were analyzed. Plasmon loss peak with energy separation (18.8-19.1eV) for Al2p main peak and (14.7-15.3eV) for Al2s main peak is likely due to bulk plasmon. XPS spectra of O1s peak showed different onset and energy seperation for each sample. Energy seperation between O1s peak and onset of plasmon is 8.4eV for 5nm lead to band gap of Al2O3 layer. But and in case of 2nm this value is 9.2eV, hence, it is likely corresponds to SiO2 interfacial layer.The reason for this might consider as top Al2O3 form island rather than homogenous oxide layer.

Based on results taken from our own experience and the general literature, in the present contribution issues related to the importance of the particle size and morphology in gold catalysis are considered. Although in reactions of small molecules like carbon monoxide nanosized or otherwise nanostructured gold surfaces are the most active catalysts, especially if forming interface with certain oxides, it turns out that in some cases - independently of the interface - the key issue is the available size of extended gold surface dictating the reaction rate. This dilemma is explored in the paper.

We describe an ex-situ monitoring technique for a small amount (∼30 mono-layers) of erbium monoantimonide (ErSb) deposited on an indium antimonide (InSb) epitaxial layer prepared on InSb(100) substrates by metal organic chemical vapor deposition (MOCVD). Our objective is to improve thermoelectric properties of nanocomposites that employ nanometer size semi-metallic ErSb particles (ErSb nanoparticles) embedded in ternary group III-V compound semiconductor host materials such as indium gallium antimonide (InGaSb) and indium antimonide arsenide (InSbAs). The formation of ErSb nanoparticles embedded in a host material is spontaneous and needs to be carefully controlled to tune the size and volume density of the ErSb nanoparticles. We used an ex-situ monitoring technique based on glancing-angle infrared-absorption, reflection absorption infra-red spectroscopy (RAIRS), to study the formation of ErSb nanoparticles to correlate the amount of delivered ErSb and surface morphology of the surface of InSb covered with ErSb.