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The present work reports the synthesis and the characterization of cobalt oxide thin films obtained by chemical vapor deposition (CVD) on indium tin oxide (ITO) substrates, using a cobalt(II) β-diketonate as precursor. The complex is characterized by electron impact mass spectrometry (EI-MS) and thermal analysis in order to investigate its decomposition pattern. The depositions are carried out in a cold wall reactor in the temperature range 350-500 °C at different oxygen pressures, to tailor film composition from CoO to Co 3 O 4 . The crystalline nanostructure is evidenced by X-ray diffraction (XRD), while the surface and in-depth chemical composition is studied by X-ray photoelectron (XPS) and X-ray excited auger electron spectroscopy (XE-AES). Atomic force microscopy (AFM) is employed to analyze the surface morphology of the films and its dependence on the synthesis conditions. Relevant results concerning the control of composition and microstructure of Co-O thin films are presented and discussed.

The preparation and properties of a series of gold nanoclusters protected by thiolated peptides based on the alpha-aminoisobutyric acid (Aib) unit are described. The peptides were devised to form 0-3 C=O...H-N intramolecular hydrogen bonds, as required by their 3(10)-helical structure. The monolayer-protected clusters (MPCs) were prepared, using a modified version of the two-phase Brust-Schiffrin preparation, and fully characterized with (1)H NMR spectrometry, IR and UV-vis absorption spectroscopies, transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and X-ray photoelectron spectroscopy (XPS). The MPCs were obtained with core diameters in the range of 1.1-2.3 nm, depending on the reaction conditions. Structured peptides formed smaller clusters. The smallest MPC obtained is in agreement with the average formula Au(38)Pep(18). The results showed that the chemical integrity of the peptide is maintained upon monolayer formation and that the average number of peptide ligands per gold cluster is typically 75-85% the value calculated for alkanethiolate MPCs of similar sizes. The IR and NMR spectra indicated that in the monolayer the peptides are involved in both intra- and interligand C=O...H-N hydrogen bonds.

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This work focuses on the photocatalytic performances and antibacterial activity of TiO 2 and Au/TiO 2 nanosystems. While the former are obtained by a sol-gel route, the latter are synthesized by an innovative hybrid RF-sputtering/sol-gel approach, followed by ex situ annealing in air up to 600 • C. Important information on nanoparticle size, shape and distribution is obtained by the combined use of glancing incidence x-ray diffraction (GIXRD) and field emission-scanning electron microscopy (FE-SEM). Subsequently, the photocatalytic performances of the obtained nanosystems in the decomposition of the azo-dye Plasmocorinth B and their antibacterial activity in the elimination of Bacillus subtilis are illustrated and discussed in comparison with films obtained from standard Degussa P25 powders. The obtained results show a significant dependence of the functional performances on the system's compositional, structural and morphological properties. In particular, the dispersion of gold nanoparticles on the TiO 2 matrix has a beneficial influence on the azo-dye photodegradation, whereas the antimicrobial activity of Au/TiO 2 films is retarded with respect to pure TiO 2 .

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Macroporous materials 1,2 based on metal oxides have become strategic for various applications like photonic crystals, 3À5 catalysts, 6À8 and sensor devices, 9À13 mainly due to their lightweight, their high surface area, and the well-defined porous architecture with a limited agglomerated morphology. 2 In sensing research the improvement in selectivity, reproducibility, and stability expected for the gas sensors based on macroporous metal oxides is still a challenge for pollutant detection. 14 Unfortunately, the delicate method needed to prepare macroporous materials still limits their wide employment in effective devices. 1,2 Macroporous metal oxides are typically synthesized by alkoxidebased solÀgel processes, employing two steps: 11,15À20 (i) the selfassembling of an ordered array of colloidal microspheres of polystyrene, polymethyl methacrylate, or silica, acting as template; (ii) the filling of interstices of the structure by metal alkoxide solution, followed by solÀgel hydrolysis and densification.The subsequent thermal treatment which removes the template leads to the macroporous structure called inverted opal, where the macropores are interconnected through holes resulting from the contact between the template spheres. 2 The application of this synthetic method becomes particularly tricky wherein highly reactive metal alkoxides are used as oxide precursors, 21,22 or if the oxide needs to be doped by sensitizing centers, 11 for example, by transition metal atoms. Moreover, when the preparation of films is required, such as in the case of semiconductor oxide-based gas sensors, the two-step approach appears unsuitable to produce metal oxide thin films having high reproducible morphology, homogeneously embedding dopants, like transition metal centers.To easily obtain macroporous metal oxides with high surface area and homogeneous dopant distribution, our group recently developed a novel one-step preparation of SnO 2 and Pt-doped SnO 2 as inverse opal thin films by dip-coating deposition of solÀgel precursors. 23 The procedure enables the self-assembled formation of the closely packed polystyrene (PS) microsphere array and the simultaneous infiltration of the precursors into the voids of the structure. Thus, the oxide solid skeleton around the spheres was obtained in one-step, unlike the conventional Received: October 22, 2010 ABSTRACT: Macroporous WO 3 films with inverted opal structure were synthesized by one-step procedure, which involves the self-assembly of the spherical templating agents and the simultaneous solÀgel condensation of the semiconductor alkoxide precursor. Transition metal doping, aimed to enhance the WO 3 electrical response, was carried out by including Cr(III) and Pt(IV) centers in the oxide matrix. It turned out that Cr remains as homogeneously dispersed Cr(III) centers inside the WO 3 host, while Pt undergoes reduction and aggregation to form nanoclusters located at the oxide surface. Upon interaction with NH 3 , the electrical conductivity of transition metal doped-WO 3 increase...

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