21. 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, izvirni znanstveni članek Opis: 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.
Ključne besede: Cu modified TiO2-SiO2 photocatalyst
Cu EXAFS, XANES, Organic pollutants
Objavljeno v RUNG: 30.08.2018; Ogledov: 4725; Prenosov: 0
Gradivo ima več datotek! Več... |
22. Surface modified titanium dioxide using transition metals : nickel as a winning transition metal for solar light photocatalysisAndraž Šuligoj, Iztok Arčon, Matjaž Mazaj, Goran Dražić, Denis Arčon, Pegie Cool, Urška Lavrenčič Štangar, Nataša Novak Tušar, 2018, izvirni znanstveni članek Opis: Titanium dioxide has been widely used as an antimicrobial agent, UV-filter and catalyst for pollution abatement. Herein, surface modifications with selected transition metals (Me) over colloidal TiO2 nanoparticles and immobilization with a colloidal SiO2 binder as composite films (MeTiO2/SiO2) on a glass carrier were used to enhance solar-light photoactivity. Colloidal TiO2 nanoparticles were modified by loading selected transition metals (Me ¼ Mn, Fe, Co, Ni, Cu, and Zn) in the form of chlorides on their surface. They were present primarily as oxo-nanoclusters and a portion as metal oxides. The structural characteristics of bare TiO2 were preserved up to an optimal metal loading of 0.5 wt%. We have shown in situ that metal-oxo-nanoclusters with a redox potential close to that of O2/O2 were able to function as co-catalysts on the TiO2 surface which was excited by solar-light irradiation. The materials were tested for photocatalytic activity by two opposite methods; one detecting O2 (reduction, Rz ink test) while the other detecting OH (oxidation, terephthalic acid test). It was shown that the enhancement of the solar-light activity of TiO2 by the deposition of transition metal oxo-nanoclusters on the surface depends strongly on the combination of the reduction potential of such species and appropriate band positions of their oxides. The latter prevented excessive self-recombination of the photogenerated charge carriers by the nanoclusters in Ni and Zn modification, which was probably the case in other metal modifications.
Overall, only Ni modification had a positive effect on solar photoactivity in both oxidation and reduction reactions.
Ključne besede: surface modified TiO2, XANES, EXAFS, Nickel, solar light photocatalyst
Objavljeno v RUNG: 01.06.2018; Ogledov: 4514; Prenosov: 0
Gradivo ima več datotek! Več... |
23. Univerza v Novi Gorici, Spremljanje, ugotavljanje in zagotavljanje kakovosti, Poročilo za študijsko leto 2015/2016Martina Bergant Marušič, Lorena Butinar, IMRE CIKAJLO, Saša Dobričič, Renata Kop, Urška Lavrenčič Štangar, Martin Knez, Boštjan Potokar, Branka Mozetič Vodopivec, Egon Pavlica, Samo Stanič, Tea Stibilj Nemec, Arthur Stepanov, Veronika Piccinini, Tamara Podveršič, Peter Purg, Aljaž Rener, Nives Štefančič, Ana Toroš, Tanja Urbančič, Vanesa Valentinčič, Aleš Vaupotič, Sabina Zelinšček, 2016, elaborat, predštudija, študija Ključne besede: zagotavljanje kakovosti, visoko šolstvo, univerza
Objavljeno v RUNG: 05.02.2018; Ogledov: 5143; Prenosov: 0
Gradivo ima več datotek! Več... |
24. Univerza v Novi Gorici, Spremljanje, ugotavljanje in zagotavljanje kakovosti, Poročilo za študijsko leto 2014/2015Martina Bergant Marušič, Aleš Bogovič, Lorena Butinar, IMRE CIKAJLO, Saša Dobričič, Elsa Fabbretti, Renata Kop, Urška Lavrenčič Štangar, Martin Knez, Katja Mihurko, Branka Mozetič Vodopivec, Egon Pavlica, Samo Stanič, Tea Stibilj Nemec, Arthur Stepanov, Boštjan Potokar, Veronika Piccinini, Peter Purg, Aljaž Rener, Nives Štefančič, Ana Toroš, Tanja Urbančič, Vanesa Valentinčič, Aleš Vaupotič, Sabina Zelinšček, 2015, elaborat, predštudija, študija Ključne besede: zagotavljanje kakovosti, visoko šolstvo, univerza
Objavljeno v RUNG: 05.02.2018; Ogledov: 5558; Prenosov: 0
Gradivo ima več datotek! Več... |
25. Univerza v Novi Gorici, Spremljanje, ugotavljanje in zagotavljanje kakovosti, Poročilo za študijsko leto 2013/2014Iztok Arčon, Martina Bergant Marušič, Aleš Bogovič, Lorena Butinar, Gvido Bratina, IMRE CIKAJLO, Saša Dobričić, Elsa Fabbretti, Mladen Franko, Renata Kop, Urška Lavrenčič Štangar, Martin Knez, Katja Mihurko, Jana Laganis, Branka Mozetič Vodopivec, Egon Pavlica, Ingrid Petrič, Samo Stanič, Tea Stibilj Nemec, Arthur Stepanov, Boštjan Potokar, Veronika Piccinini, Peter Purg, Aljaž Rener, Nives Štefančič, Ana Toroš, Tanja Urbančič, Vanesa Valentinčič, Aleš Vaupotič, Sabina Zelinšček, 2014, elaborat, predštudija, študija Ključne besede: zagotavljanje kakovosti, visoko šolstvo, univerza
Objavljeno v RUNG: 05.02.2018; Ogledov: 5234; Prenosov: 0
Gradivo ima več datotek! Več... |
26. Univerza v Novi Gorici, Fakulteta za znanosti o okolju: Spremljanje, ugotavljanje in zagotavljanje kakovosti Poročilo za študijsko leto 2013/2014 z analizo vseh področij delovanja iz vseh let po zadnji akreditacijiIztok Arčon, Marina Artico, Janja Humar, Renata Kop, Veronika Piccinini, Urška Lavrenčič Štangar, Tea Stibilj Nemec, Lucija Vidrih, Sabina Zelinšček, 2014, elaborat, predštudija, študija Ključne besede: zagotavljanje kakovosti, visoko šolstvo, akreditacija, univerza
Objavljeno v RUNG: 05.02.2018; Ogledov: 4981; Prenosov: 0
Gradivo ima več datotek! Več... |
27. Predlog sprememb študijskega programa 2. stopnje Okolje, Univerza v Novi Gorici, Fakulteta za znanosti o okoljuAsta Gregorič, Veronika Piccinini, Urška Lavrenčič Štangar, 2014, elaborat, predštudija, študija Ključne besede: študijski programi, univerza, kakovost v visokem šolstvu
Objavljeno v RUNG: 05.02.2018; Ogledov: 4787; Prenosov: 0
Gradivo ima več datotek! Več... |
28. Predlog sprememb študijskega programa 1. stopnje Okolje, Univerza v Novi Gorici, Fakulteta za znanosti o okoljuAsta Gregorič, Veronika Piccinini, Urška Lavrenčič Štangar, 2014, elaborat, predštudija, študija Ključne besede: študijski programi, kakovost, visoko šolstvo, izobraževanje
Objavljeno v RUNG: 02.02.2018; Ogledov: 5125; Prenosov: 0
Gradivo ima več datotek! Več... |
29. Design and evaluation of a compact photocatalytic reactor for water treatmentMarko Kete, Olena Pliekhova, Lev Matoh, Urška Lavrenčič Štangar, 2017, izvirni znanstveni članek Ključne besede: Photocatalysis, Photocatalytic ozonation, TiO2, Al2O3 monolith, LAS, PBIC, Reactive blue 19, Phenol
Objavljeno v RUNG: 24.08.2017; Ogledov: 5725; Prenosov: 0
Gradivo ima več datotek! Več... |
30. |
