41. Scanning Photoelectron Spectro‐Microscopy: A Modern Tool for the Study of Materials at the NanoscalePatrick Zeller, Matteo Amati, Hikmet Sezen, Mattia Scardamaglia, Claudia Struzzi, Carla Bittencourt, Gabriel Lantz, Mahdi Hajlaoui, Evangelos Papalazarou, Marino Marsi, Mattia Fanetti, Stefano Ambrosini, Silvia Rubini, Luca Gregoratti, 2018, review article Keywords: Scanning photoemission microscopy, graphene, GaAs, nanowires, Fermi Level, Mott-Hubbard transition
Published in RUNG: 07.12.2018; Views: 3542; Downloads: 0
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42. Growth, morphology and stability of Au in contact with the Bi[sub]2Se[sub]3(0 0 0 1) surfaceMattia Fanetti, Iuliia Mikulska, Katja Ferfolja, Paolo Moras, Polina M. Sheverdyaeva, M. Panighel, A. Lodi-Rizzini, I. Píš, S. Nappini, Matjaž Valant, Sandra Gardonio, 2018, original scientific article Keywords: metal contact, topological insulator contact, growth mode, electronic properties, chemical properties, photoemission spectroscopy, microscopy
Published in RUNG: 05.12.2018; Views: 3638; Downloads: 0
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45. The effect of Zr loading on photocatalytic activity of Cu modified TiO2Olena Pliekhova, O. L. Pliekhov, Mattia Fanetti, Iztok Arčon, Nataša Novak Tušar, Urška Lavrenčič Štangar, 2018, published scientific conference contribution Keywords: Titanium diokside, acidic sites, surface titration, copper, zirconium
Published in RUNG: 10.09.2018; Views: 3852; Downloads: 0
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48. Effects of Different Copper Loadings on the Photocatalytic Activity of TiO2-SiO2 Prepared at a Low Temperature for the Oxidation of Organic Pollutants in WaterT. Čižmar, Iztok Arčon, Mattia Fanetti, Urška Lavrenčič Štangar, 2018, original scientific article Abstract: The objective of this research is to examine how Cu modification can improve the photocatalytic activity of TiO2-SiO2, to explainthe correlation between the Cu concentration and the chemical state of Cu cations in the TiO2-SiO2 matrix, and the photocatalytic activity under UV/solar irradiation. The Cu-modified TiO2-SiO2 photocatalysts were prepared by a low-temperature sol–gel method from organic Cu, Si and Ti precursors with various Cu concentrations (0.05–3 mol %). The sol–gels were dried at 150 8C to obtain the photocatalysts in a powder form. The photocatalytic activity was determined by using a fluorescence- based method of terephthalic acid decomposition. An up to three times increase in photocatalytic activity is obtained if the TiO2-SiO2 matrix is modified with Cu in a narrow concentration
range from 0.05 to 0.1 mol%. At higher Cu loadings,
the photocatalytic activity of the Cu-modified photocatalysts is lower than that of the un-modified reference TiO2-SiO2 photocatalyst. XRD was used to show that all Cu-modified TiO2-SiO2 composites with different Cu concentrations have the same crystalline structure as un-modified TiO2-SiO2 composites. The addition of Cu does not change the relative ratio between the anatase and brookite phases or unit cell parameters of the two TiO2 crystalline structures. We used Cu K-edge X-ray absorption near edge structure and extended X-ray absorption fine structure analyses to determine the valence state and local structure of Cu cations in the Cu-modified TiO2-SiO2 photocatalysts. The results elucidate the mechanism responsible for the improved photocatalytic activity. In samples with a low Cu content,
which exhibit the highest activity, Cu@O@Ti connections
are formed, which suggests that the activity enhancement is
caused by the attachment of CuII cations on the surface of the photocatalytically active TiO2 nanoparticles, so CuII cations may act as free-electron traps, which reduce the intensity of recombination between electrons and holes at the TiO2 photocatalyst surface. At higher Cu loadings no additional Cu@O@Ti connections are formed, instead only Cu@O@Cu connections are established. This indicates the formation of amorphous or nanocrystalline
copper oxide, which hinders the photocatalytic activity
of TiO2.
Keywords: Cu modified TiO2-SiO2 photocatalyst
Cu EXAFS, XANES, Organic pollutants
Published in RUNG: 30.08.2018; Views: 3532; Downloads: 0
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49. High-temperature stabilization of bulk amorphous Al2O3Andraž Mavrič, Mattia Fanetti, Gregor Mali, Matjaž Valant, 2018, original scientific article Abstract: We present a method for high temperature stabilization of bulk amorphous aluminium oxide. The stabilization is achieved by dispersing polysilane dendritic molecules in aluminium hydroxide gel, which upon thermal treatment gives amorphous aluminium oxide stable up to 900 °C. The dispersed macromolecules covalently bind to the alumina matrix and induce homogeneously distributed strain fields that keep the alumina amorphous. The thermal conversion of the precursor system was followed by thermogravimetry with an evolved gas analysis, infrared spectroscopy and 29Si NMR. The amorphous structure of aluminium oxide was confirmed with an X-ray and electron diffraction. Additionally, the amorphous state was supported by presence of penta-coordinated aluminium detected by 27Al NMR and a low bandgap measured by a UV–visible absorption spectroscopy.
Keywords: Amorphous aluminium oxide, Polysilane, Nanocomposite, Stabilization
Published in RUNG: 30.07.2018; Views: 4293; Downloads: 16
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