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alpha-Mn3O4 (hausinannite) nanostructured films were fabricated by chemical vapor deposition (CVD) on indium tin oxide (ITO)-coated glass substrates from a beta-diketonate-diamine Mn(II) precursor. Materials were grown in a N2 + O2 atmosphere in the presence of water vapor, investigating the influence of growth temperature and total pressure on the system structural, compositional, morphological, and optical properties through a multitechnique characterization approach. The obtained alpha-Mn3O4 nano- deposits were ultimately tested as catalysts in the photo- electrochemical (PEC) splitting of water under simulated solar illumination, with particular focus on the interplay relationships between the adopted preparative conditions and the resulting functional performances. The amphoteric semiconducting behavior along with the PEC properties markedly dependent on the deposit nanoscale organization opens interesting avenues to an eventual implementation of the target materials in view of sustainable applications.

We report on a combined chemical vapor deposition (CVD)/radio frequency (RF) sputtering synthetic strategy for the controlled surface modification of ZnO nanostructures by Ti-containing species. Specifically, the proposed approach consists in the CVD of grown-on-tip ZnO nanopyramids, followed by titanium RF sputtering under mild conditions. The results obtained by a thorough characterization demonstrate the successful ZnO surface functionalization with dispersed Ti-containing species in low amounts. This phenomenon, in turn, yields a remarkable enhancement of photoactivated superhydrophilic behavior, self-cleaning ability, and photocatalytic performances in comparison to bare ZnO. The reasons accounting for such an improvement are unravelled by a multitechnique analysis, elucidating the interplay between material chemico-physical properties and the corresponding functional behavior. Overall, the proposed strategy stands as an amenable tool for the mastering of semiconductor-based functional nanoarchitectures through ad hoc engineering of the system surface.

Supported p-type alpha-Mn3O4 nanosystems were fabricated by means of chemical vapor deposition (CVD) on polycrystalline alumina substrates at temperatures of 400 and 500 °C, using Mn(hfa)2·TMEDA (hfa = 1,1,1,5,5,5-hexafluoro-2,4-pentanedionate; TMEDA = N,N,N?,N?-tetramethylethylenediamine) as precursor compound. The structure, chemical composition, and morphology of the obtained deposits were characterized in detail, devoting particular attention to the influence of the used reaction atmosphere (dry O2 vs. O2 + H2O) on the system characteristics. For the first time, the gas-sensing performances of the obtained CVD Mn3O4 nanomaterials were investigated toward ethanol and acetone vapors, with concentrations ranging from 10 to 50 and from 25 to 100 ppm, respectively. The developed systems showed the best activity ever reported in the literature for Mn3O4 chemoresistive sensors in the detection of the target gases, a result that, along with their low detection limits and good selectivity, is an appealing starting point for eventual technological applications.

This work encompasses a facile method for tailoring surface defects in electrospun TiO2 nanofibers by employing hydrogen plasma treatments. This amiable processing method was proven with SQUID, EPR, and XPS to be highly effective in generating oxygen vacancies, accompanied by the reduction of Ti4+ centers to Ti3+, resulting in the formation of black titania. The treatment temperature was found to affect the Ti3+/Ti4+ ratios and surface valence, while preserving the original 1D morphology of the titania fibers. Ab initio DFT calculations showed that a high concentration of oxygen vacancies is highly efficient in producing midgap states that enhance the system absorption over the whole visible range, as observed with UV/vis/NIR diffuse reflectance spectroscopy. Pristine TiO2 nanofibers produced a photocurrent density of 0.02 mA/cm2 at 1.23 V vs RHE, whereas the hydrogen plasma treatment resulted in up to a 10-fold increase in the photoelectrochemical performance.

p-Type Co(3)O(4) nanostructured films are synthesized by a plasma-assisted process and tested in the photocatalytic production of H(2) from water/ethanol solutions under both near-UV and solar irradiation. It is demonstrated that the introduction of fluorine into p-type Co(3)O(4) results in a remarkable performance improvement with respect to the corresponding undoped oxide, highlighting F-doped Co(3)O(4) films as highly promising systems for hydrogen generation. Notably, the obtained yields were among the best ever reported for similar semiconductor-based photocatalytic processes.

We report on the fabrication of Cu(x)O-TiO(2) (x = 1, 2) nanomaterials by an unprecedented vapor-phase approach. The adopted strategy involves the growth of porous Cu(x)O matrices by means of chemical vapor deposition (CVD), followed by the controlled dispersion of TiO(2) nanoparticles. The syntheses are performed on Si(100) substrates at temperatures of 400-550 °C under wet oxygen atmospheres, adopting Cu(hfa)(2)·TMEDA (hfa = 1,1,1,5,5,5-hexafluoro-2,4-pentanedionate; TMEDA = N,N,N',N'-tetramethylethylenediamine) and Ti(O-(i)Pr)(2)(dpm)(2) (O-(i)Pr = isopropoxy; dpm = 2,2,6,6-tetramethyl-3,5-heptanedionate) as copper and titanium precursors, respectively. Subsequently, finely dispersed gold nanoparticles are introduced in the as-prepared systems via radio frequency (RF)-sputtering under mild conditions. The synthesis process results in the formation of systems with chemical composition and nano-organization strongly dependent on the nature of the initial Cu(x)O matrix and on the deposited TiO(2) amount. The decoration with low-size gold clusters paves the way to the engineering of hierarchically organized nanomaterials.

On the basis of the study of the thermal behavior of [Mg(tmhd)(2)(TMEDA)] (1; tmhd = 2,2,6,6-tetramethyl-3,5-heptanedionate; TMEDA = N,N,N',N'-tetramethylethylenediamine), a novel procedure for magnesium oxide thin film growth has been developed for chemical vapor deposition (CVD) applications. Complementary studies (thermogravimetric measurements and IR and NMR spectroscopy) enabled revelation of the dissociation of TMEDA from 1, confirmed by the detection of both free TMEDA in the vapor phase and less volatile [Mg(2)(tmhd)(4)] (2) as a residue after sublimation. The effect of this dissociation is an unwanted changeable sublimation rate of the precursor 1 during the CVD process. The endeavor of a constant deposition rate by simultaneously exploiting the good volatility of 1 was achieved through its synthesis in situ by using 2 with a diamine enriched carrier. Laser reflectance interferometry (LRI) measurements testified that such a method ensured a good and constant deposition rate throughout the growth experiment, independently of the adopted processing conditions. In addition, X-ray diffraction (XRD) measurements revealed the obtainment of textured and polycrystalline MgO coatings on sapphire and on Si(100). The system chemical composition was investigated by X-ray photoelectron spectroscopy (XPS).

A copper(II) hexafluoroacetylacetonate (1,1,1,5,5,5-hexafluoro-2,4-pentanedionate, hfa) adduct with N,N,N¡ä,N¡ä-tetramethylethylenediamine (TMEDA) [Cu(hfa)2¡¤TMEDA] is used for the first time as precursor for the chemical vapor deposition (CVD) of copper oxide nanosystems. The syntheses are carried out under both O2 and O2+H2O reaction atmospheres on Si(100) substrates, at temperatures ranging between 250 and 550 ¡ãC. Subsequently, the interrelations between the preparative conditions and the system composition, nanostructure, and morphology are elucidated by means of complementary analytical techniques [Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron and X-ray excited auger electron spectroscopies (XPS and XE-AES), glancing incidence X-ray diffraction (GIXRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM)]. The obtained data revealed a gradual transformation from Cu2O, to Cu2O + CuO, to CuO nanosystems upon increasing the deposition temperature from 250 to 550 ¡ãC under both growth atmospheres. Such a phenomenon was accompanied by a progressive morphological evolution from continuous films to 1D hyperbranched nanostructures. Water vapor introduction in the deposition environment enabled to lower the deposition temperature and resulted in a higher aggregate interconnection, attributed to a higher density of nucleation centers.

The stabilization of the reactive amide complexes of niobium and tantalum with malonates as chelating ligands leads to stable six-coordinated monomeric complexes ([M(NMe2)4(dbml)]; M ) Nb, Ta), namely tetrakis(dimethylamido)(di-tert-butylmalonato)niobium(V) (1) and tetrakis(dimethylamido)(di-tert-butylmalonato) tantalum(V) (2). Compounds 1 and 2 were characterized by 1H NMR, 13C NMR, EI-mass spectroscopy, elemental analysis, and single-crystal X-ray diffraction studies. The thermal properties of the compounds were studied by thermogravimetric analysis. Both the complexes possess good thermal characteristics, improved resistance to air and moisture, and high solubility and stability in solvents compared to their respective parent alkyl amides. Compound 1 was studied for metalorganic chemical vapor deposition (MOCVD) of Nb2O5 while compound 2 was studied for liquid injection metalorganic chemical vapor deposition (LI-MOCVD) of Ta2O5 thin films. The films were deposited at substrate temperatures from 400 to 800 °C, and for both Nb2O5 and Ta2O5 the maximum growth rate was at 600 °C. The films were characterized by X-ray diffraction, scanning electron microscopy, and atomic force microscopy for their crystallinity and morphology. Thin film composition was analyzed by X-ray photoelectron spectroscopy, Rutherford backscattering, and depth profiling the composition with secondary neutral mass spectrometry. Electrical properties of the films were studied in terms of the C-V characteristics.

HPLC separation of flavonoids and furocoumarins in the crude juices of three cultivars of Citrus bergamia Risso ("Castagnaro", "Fantastico", and "Femminello") was carried out on a C18 reversed phase column. The analysis was performed in a single run using a DAD detector coupled with an ESI-MS-MS source. Two furocoumarins (bergapten and bergamottin) were detected and quantified simultaneously with the sixteen flavonoid components previously found in industrial bergamot juice. Full characterization of the furocoumarins was performed by (1)H NMR analysis on samples separated by means of preparative HPLC. The free-radical scavenging ability of cultivar juices was assessed by using DPPH radical. The data presented show that the "Femminello" cultivar, even though it is the least common of the three, is by far the richest in health-promoting bioactive compounds (both flavonoids and furocoumarins). Given the range of applications of furocoumarins, the preparative separation described herein is proposed as a simple and rapid method to obtain this class of compounds in good yield from crude juice.

A sulfur-containing single molecule magnet, [Mn12O12(O2CC6H4SCH3)16(H2O)4], was assembled from solution on a Au(111) surface affording both submonolayer and monolayer coverages. The adsorbate morphology and the degree of coverage were inspected by scanning tunneling microscopy (STM), while X-ray photoelectron spectroscopy (XPS) allowed the determination of the chemical nature of the adsorbate on a qualitative and quantitative basis. The properties of the adsorbates were found to be strongly dependent on the solvent used to dissolve the magnetic complex. In particular, systems prepared from tetrahydrofuran solutions gave arrays of isolated and partially ordered clusters on the gold substrate, while samples prepared from dichloromethane exhibited a homogeneous monolayer coverage of the whole Au(111) surface. These findings are relevant to the optimization of magnetic addressing of single molecule magnets on surfaces.

Lanthanum cobaltite (LaCoO3) thin films were synthesized by an innovative route based on the combination of chemical vapor deposition (CVD) and sol−gel (SG) methods. In particular, the approach is based on the sequential deposition of binary oxide systems (Co−O on La−O) and on the ex situ thermal treatment of the final product (T = 400−900 °C, t = 1−8 h), aimed at favoring solid-state reactions for the formation of a ternary La−Co−O nanosystem. To highlight the peculiar effects of these procedures on the characteristics of the final product, both SG and CVD routes were used for the preparation of single-phase La−O and Co−O species. The process resulted in the formation of LaCoO3 nanostructured films with an average crystallite size lower than 20 nm. The required processing conditions were strongly dependent on the specific synthetic pathway: (i) SG of Co−O on CVD La−O; (ii) CVD of Co−O on SG La−O. In this framework, particular attention was focused on the analogies and differences between the two sequenc...

An original synthetic approach to Au/TiO 2 nanosystems is developed. The adopted technique is based on the RF-sputtering of gold (guest) on porous titania xerogels (host) obtained by the sol-gel route. Such a combined synthetic pathway joins the peculiarities offered by the features of the sol-gel layers (porosity, nonbridging groups) and the advantages of plasmochemical methods (conformal coverage, infiltration power). In particular, host titania substrates were first prepared on silica by dip-coating from ethanolic solutions of Ti(OPr i ) 4 (OPr i =iso-propoxy) and Hacac (2,4-pentanedione). Subsequently, Au depositions were performed on the as-prepared xerogels in Ar plasmas at low temperatures. The resulting samples were finally annealed in air between 200 and 600 °C with the aim of tailoring the system features as a function of thermal treatment and gold content. Their structural, compositional, and morphological evolution was investigated by Glancing Incidence X-ray Diffraction (GIXRD), Transmission Electron Microscopy (TEM), optical absorption spectroscopy, X-ray Photoelectron Spectroscopy (XPS), and Atomic Force Microscopy (AFM). The adopted strategy enabled the synthesis of Au/YiO 2 nanosystems with characteristics strongly dependent on the deposited gold amount and processing conditions. In this way, materials with tunable structure, composition, and optical properties could be synthesized.

The thermal evolution of sol-gel SnO2-based thin films was explored by investigating their structural and morphological features. Nanostructured SnO2 and Pt-doped SnO2 layers were obtained using tetra(tert-butoxy)tin(IV) and Pt(II) acetlylacetonate as precursors. Films were prepared by spin coating from ethanol solutions with different viscosity. After drying at room temperature, they were annealed in air at 673 and 973 K. The surface morphology was analyzed by scanning electron microscopy, atomic force microscopy, and scanning nearfield optical microscopy. The structural characterization was performed by means of glancing incidence X-ray diffraction and microdiffraction. Both drying at room temperature and thermal treatment at 673 K resulted in the formation of holes on the surface and inside the films. Their distribution and average dimension were found to depend mainly on the viscosity of the sol precursor, and on the presence of Pt in the films. After annealing at 973 K, surface segregation of PtOx phases and partial filling of the surface holes occurred. The effects of morphology on the electrical transport properties are discussed on the basis of sensitivity, S, measurements (S ) Rair/RCO, where Rair and RCO stand for the resistance in air and CO/ air, respectively).

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 Co3O4. 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.

An η3-allylic complex of ruthenium(II) is used as a precursor for the chemical vapor deposition (CVD) of Ru and RuO2 thin films at low temperatures. The depositions are carried out on α-Al2O3 and surface-oxidized Si(100) in N2, N2 + H2, N2 + O2, or O2 flow to tailor the film composition from pure metal Ru to RuO2. The microstructure features of the samples are analyzed by X-ray diffraction and Raman spectroscopy, whereas their surface composition is studied by X-ray photoelectron spectroscopy. Surface and in-depth analyses of the coatings are also performed by secondary ion mass spectrometry, which allows to distinguish the composition of different coating regions along their thickness. The surface morphology and its dependence on the synthesis conditions are investigated by atomic force microscopy. The electrical and optical studies confirm the metallic character of Ru and RuO2 films.