Repozitorij Univerze v Novi Gorici

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1.
Development and characterization of improved materials for antifouling applications
Urška Lavrenčič Štangar, Iztok Arčon, Tihana Čižmar, 2015, objavljeni povzetek znanstvenega prispevka na konferenci

Najdeno v: ključnih besedah
Povzetek najdenega: ...method, photocatalysis, hybrid materials, Cu K-edge XANES, photocatalytic activity...
Ključne besede: sol-gel method, photocatalysis, hybrid materials, Cu K-edge XANES, photocatalytic activity
Objavljeno: 15.02.2016; Ogledov: 1598; Prenosov: 0
.pdf Polno besedilo (131,22 KB)

2.
Thermal properties of surface-modified [alpha] and [epsilon]-Fe [sub] 2O [sub] 3 photocatalysts determined by beam deflection spectroscopy
Fernando Fresno, Mladen Franko, Dorota Korte Kobylinska, Giorgio Carraro, 2014, objavljeni znanstveni prispevek na konferenci

Najdeno v: ključnih besedah
Povzetek najdenega: ... photocatalytic activity, photothermal beam deflection spectroscopy, thin films,...
Ključne besede: photocatalytic activity, photothermal beam deflection spectroscopy, thin films
Objavljeno: 16.06.2016; Ogledov: 1598; Prenosov: 57
URL Polno besedilo (0,00 KB)

3.
Correlations between photocatalytic activity and chemical structure in copper doped TiO2-SiO2 with surface/incorporated Cu2+ sites
Tihana Čižmar, Iztok Arčon, Urška Lavrenčič Štangar, 2016, objavljeni povzetek znanstvenega prispevka na konferenci

Opis: Sol−gel method was used to synthesize copper doped TiO2-SiO2 with varied dopant concentrations using tetraisopropoxide (TTIP) and copper acetlyacetonate (CuAcAc) as titania and copper sources. Structural information of Cu cation incorporation and its chemical state in the coatings are determined with Cu K-edge EXAFS and XANES analysis. The correlations between chemical state of the Cu dopant and the photocatalytic properties of the new active coatings are discussed.
Najdeno v: ključnih besedah
Ključne besede: dip-coating, titanium dioxide, metal doping, Cu K-edge XANES, photocatalytic activity
Objavljeno: 07.07.2016; Ogledov: 1911; Prenosov: 0

4.
Correlations between photocatalytic activity and Cu structure in Cu-modified TiO2-SiO2
T. Čižmar, objavljeni povzetek znanstvenega prispevka na konferenci

Najdeno v: ključnih besedah
Ključne besede: Titanium dioxide, Cu-modified, TiO2-SiO2, photocatalysts, photocatalytic activity, Cu K-edge XANES, EXAFS
Objavljeno: 26.06.2017; Ogledov: 1156; Prenosov: 0
.pdf Polno besedilo (641,42 KB)

5.
Chemical structure in Cu-modified TiO2-SiO2 nanocomposites calcined at 500 °C for 1 h in air
T. Čižmar, Iztok Arčon, Urška Lavrenčič Štangar, 2017, objavljeni povzetek znanstvenega prispevka na konferenci

Najdeno v: ključnih besedah
Povzetek najdenega: ...dioxide, metal doping, Cu K-edge XANES, EXAFS, photocatalytic activity...
Ključne besede: Cu-modified TiO2-SiO2 photocatalysts, titanium dioxide, metal doping, Cu K-edge XANES, EXAFS, photocatalytic activity
Objavljeno: 22.08.2017; Ogledov: 10777; Prenosov: 0
Gradivo ima več datotek! Več...

6.
Correlations between photocatalytic activity and chemical structure of Cu-modified TiO2-SiO2 nanoparticle composites
T. Čižmar, doktorska disertacija

Opis: The objective of this dissertation was to examine how copper modification can improve the photocatalytic activity of TiO2-SiO2 and to explain the correlation between Cu concentration and chemical state of Cu cations in the TiO2-SiO2 matrix, as well as the photocatalytic activity under the UV/solar irradiation. The Cu-modified TiO2-SiO2 photocatalysts were prepared by a low temperature sol-gel method based on organic copper, silicon and titanium precursors with varied Cu concentrations (from 0.05 to 3 mol%). The sol-gels were dried at 150 °C to obtain the photocatalysts in the powder form. To test thermal stability, additional set of photocatalysts was obtained by calcinating dried samples in air at 500 °C for 1 h. The photocatalytic activity was determined by a fluorescence-based method of terephthalic acid decomposition. Up to three times increase in photocatalytic activity of air-dried samples is obtained when 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 Cu-modified photocatalyst is smaller than in the unmodified reference TiO2-SiO2 photocatalyst. Calcined samples showed significantly reduced photocatalytic activity compared to air-dried samples. XRD analysis showed that all Cu-modified TiO2-SiO2 nanocomposites with different Cu concentrations have the same crystalline structure as unmodified TiO2-SiO2 nanocomposites (air-dried or calcined). The addition of Cu does not change the relative ratio between the anatase and brookite phase or unit cell parameters of the two TiO2 crystalline structures. TEM analysis showed that the addition of Cu does not change the morphology of TiO2-SiO2 catalyst dried at 150 °C. The Cu K-edge XANES and EXAFS analysis were used to determine valence state and local structure of Cu cations in Cu-modified TiO2-SiO2 photocatalyst. The results elucidate the mechanism responsible for the improved or hindered photocatalytic activity. In the air-dried samples with low Cu content, which exhibit largest activity, Cu-O-Ti connections are formed, suggesting that the activity enhancement is due to Cu(II) cations attachment on the surface of the photocatalytically active TiO2 nanoparticles, so Cu(II) cations may act as free electron traps, reducing the intensity of recombination between electrons and holes at the TiO2 photocatalyst’s surface. At higher Cu loadings no additional Cu-O-Ti connections are formed, instead only Cu-O-Cu connections are established, indicating the formation of amorphous or nanocrystalline Cu(II) oxide, which hinders the photocatalytic activity of TiO2. Calcination of Cu-modified TiO2-SiO2 photocatalysts at 500 °C induces significant structural changes: Cu-O-Ti connections are lost, Cu partially incorporates into the SiO2 matrix and amorphous copper oxides, which again reduce the photocatalytic activity of the material, are formed.
Najdeno v: ključnih besedah
Ključne besede: titanium dioxide, Cu-modified TiO2-SiO2 photocatalyst, photocatalytic activity, Cu K-edge XANES, EXAFS.
Objavljeno: 17.12.2018; Ogledov: 578; Prenosov: 33
.pdf Polno besedilo (3,05 MB)

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