81. Chemical Instability of an Interface between Silver and Bi2Se3 Topological Insulator at Room TemperatureKatja Ferfolja, Matjaž Valant, Iuliia Mikulska, Sandra Gardonio, Mattia Fanetti, 2018, original scientific article Abstract: Understanding an interaction at an interface between a topological insulator and a metal is of critical importance when designing electronic and spintronic devices or when such systems are used in catalysis. In this paper, we report on a chemical instability of the interface between Bi2Se3 and Ag studied by X-ray powder diffraction and electron microscopy. We present strong experimental evidence of a redox solid-state reaction occurring at the interface with kinetics that is significant already at room temperature. The reaction yields Ag2Se, AgBiSe2, and Bi. The unexpected room-temperature chemical instability of the interface should be considered for all future theoretical and applicative studies involving the interface between Bi2Se3 and Ag.
Keywords: topological insulators, Ag, thin metal films, interfaces, redox reaction
Published in RUNG: 17.06.2020; Views: 3069; Downloads: 0
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84. Improved photocatalytic activity of anatase-rutile nanocomposites induced by low-temperature sol-gel Sn-modification of TiO2Ksenija Maver, Iztok Arčon, Urška Lavrenčič Štangar, Mattia Fanetti, Saim Emin, Matjaž Valant, 2020, original scientific article Abstract: The Sn-modified TiO2 photocatalysts are prepared by low-temperature sol-gel processing based on organic titanium
and tin precursors with varied Sn concentrations (from 0.1–20 mol .%). The role of Sn dopant as the
promotor of the formation of TiO2 rutile crystalline phase is explained and the optimal Sn concentration for
preparation of efficient Sn-modified titania photocatalyst is determined. Up to 40 % increase in photocatalytic
activity is achieved in Sn-modified TiO2 photocatalytic thin films dried at 150 °C with low Sn concentrations in
the range from 0.1 to 1 mol .%. At low Sn concentrations optimal ratio between anatase and rutile (nano)crystals
is obtained, which facilitates charge separation at the TiO2 photocatalyst’s surface. When the concentration of Sn
increases above 5 mol.% or when the films are calcined at 500 °C, the relative amount of rutile phase with
inferior photocatalytic activity, increases and the nanocrystals of titania grow, leading to fewer active sites per
unit mass and the reduction of activity in comparison to unmodified TiO2.
Keywords: Anatase-rutile
Sn-modified TiO2
XAS analysis
Photocatalytic activity
Published in RUNG: 10.02.2020; Views: 3170; Downloads: 0
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87. Spremljanje, ugotavljanje in zagotavljanje kakovosti : Poročilo za študijsko leto 2018/2019, Fakulteta za znanosti o okolju, Univerza Nova GoricaBlaž Belec, Iztok Arčon, Marina Artico, Tea Stibilj Nemec, Nivec Štefančič, Maja Terčon, Matjaž Valant, Sabina Zelinšček, treatise, preliminary study, study Keywords: Samoevalvacijsko poročilo
Published in RUNG: 06.01.2020; Views: 3289; Downloads: 0
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