Repository of University of Nova Gorica

Search the repository
A+ | A- | Help | SLO | ENG

Query: search in
search in
search in
search in
* old and bologna study programme

Options:
  Reset


21 - 30 / 57
First pagePrevious page123456Next pageLast page
21.
22.
23.
Photoelectrocatalytic water splitting and dye degradation with fluorine doped tin oxides films
Manel Machreki, Takwa Chouki, Saim Emin, 2019, published scientific conference contribution abstract

Abstract: We report the photoelectrochemical (PEC) water splitting with flourine doped tin oxide (FTO) films. This is the first study where efficient water splitting is achieved with FTO films under light illumination. Potentiostatic test at 1.7 V vs reversible hydrogen electrode (RHE) show that FTO material is very stable for water oxidation without occurence of a noticable current drop over a span of 6 hours. Mass spectrometry analysis of evolved gasses confermed the formation of oxygen and hydrogen in the two half cells (separated by a membrane). Moreover, it was demonstrated that the water splitting reaction involve formation of hydroxyl radicals (•OH) which are known oxidants for organics. We applied these FTO films for degradation of a model pollutant rhodamine B dye (1×10−5 mol/l). PEC assisted degradation of rhodamine B took about 30 min to achieve complete degradation of 60 ml model dye solution.
Keywords: FTO, thin films, dye degradation
Published in RUNG: 13.05.2021; Views: 1981; Downloads: 0
This document has many files! More...

24.
Electrocatalytic hydrogen evolution with textured iron phosphides thin films
Saim Emin, 2019, published scientific conference contribution abstract

Abstract: We used wet-chemistry techniques to prepare colloidal iron phosphides (F2P) nanoparticles (NPs). The synthesis of Fe2P NPs was conducted using the so called hot-matrix method [1]. The sizes of obtained Fe2P NPs are in the order of 2 - 5 nm. The colloidal Fe2P NPs are coated with hydrophobic molecules which allow preparation of stable dispersion in organic solvents like choloroform (CHCl3). The colloidal F2P NPs are very suitable for the preparation of thin films via spin-coated, spray coated or inkjet-printed on various conductive substrates. The obtained Fe2P films were used in hydrogen evolution reaction (HER). In addition, to HER the Fe2P films were used for electrocatalytic degradation of organics.
Keywords: Fe2P, electroctalysis, thin films
Published in RUNG: 13.05.2021; Views: 2293; Downloads: 0
This document has many files! More...

25.
Solvothermal synthesis of iron phosphides and their application for efficient electrocatalytic hydrogen evolution
Takwa Chouki, Manel Machreki, Saim Emin, 2020, published scientific conference contribution abstract

Abstract: We report the solvothermal synthesis of iron phosphide electrocatalysts using a low-cost phosphorus precursor [1]. The synthetic protocol allows for the preparation of a Fe2P phase at 300°C and FeP phase at 350°C. To enhance the catalytic activities of obtained iron phosphide particles, heat-treatments were carried out at elevated temperatures. Annealing at 500°C induced structural changes in the samples: (i) Fe2P provided a pure Fe3P phase (Fe3P−500°C) and (ii) FeP transformed into a mixture of iron phosphide phases (Fe2P/FeP−500°C). The electrocatalytic activities of heat-treated Fe2P−450°C, Fe3P−500°C, and Fe2P/FeP−500°C catalysts were studied for hydrogen evolution reaction (HER) in 0.5 M sulfuric acid (H2SO4). The HER activities of the iron phosphide catalyst were found to be phase dependent. The lowest recorded overpotential of 110 mV at 10 mA cm−2 vs. a reversible hydrogen electrode was achieved with Fe2P/FeP−500°C catalyst. The present approach allows the preparation of immobilized iron phsphide catalyst onto carbon support which is essential for application purpose. The procedure developed by us is an elegant approach to tune the composition of iron phosphide catalyst and control the morphology of particles.
Keywords: solvothermal synthesis, iron phosphide, electrocatalyst, hydrogen evolution, overpotential
Published in RUNG: 13.05.2021; Views: 2061; Downloads: 0
This document has many files! More...

26.
Synthesis of efficient iron phosphide catalyst for electrocatalytic hydrogen generation
Takwa Chouki, D. Lazarević, B. Donkova, Saim Emin, 2021, original scientific article

Abstract: A solvothermal synthesis of iron phosphide electrocatalysts using triphenylphosphine (TPP) as phosphorus precursor is presented. The synthetic protocol generates Fe2P/FeP phase at 350°C. After deposition of the catalyst onto graphite substrate heat-treatment at higher temperature was carried out. Annealing at 500°C under reductive atmosphere induced structural changes in the Fe2P/FeP samples which yielded a pure Fe2P phase. The electrocatalytic activity of the Fe2P catalyst was studied for hydrogen evolution reaction (HER) in 0.5 M H2SO4. The recorded overpotential for HER was about 130 mV vs. a reversible hydrogen electrode (RHE) at 10 mA cm−2
Keywords: solvothermal synthesis, iron phosphide, electrocatalyst, hydrogen evolution
Published in RUNG: 10.05.2021; Views: 2017; Downloads: 0
This document has many files! More...

27.
Preparation of porous [alpha]-Fe[sub]2O[sub]3 thin films for efficient photoelectrocatalytic degradation of basic blue 41 dye
Manel Machreki, Takwa Chouki, Mitja Martelanc, Lorena Butinar, Branka Mozetič Vodopivec, Saim Emin, 2021, original scientific article

Abstract: A novel method was developed for the preparation of porous hematite (α-Fe2O3) thin films. First, a solution containing iron precursor was spin-coated on fluorine-doped tin oxide substrate and later short heat-treated at 750 °C. The prepared α-Fe2O3 thin films were applied as dual-function catalyst in photoelectrochemical (PEC) water oxidation and textile dye degradation studies. For the first time, α-Fe2O3 thin films were used in efficient PEC degradation of a textile dye (Basic Blue 41 – B41) using in-situ generated reactive chlorine species. In comparison with photocatalytic and electrocatalytic approaches, the PEC technique allows faster degradation of B41 dye at an applied bias potential of 1.5 V versus reversible hydrogen electrode and under visible light illumination. In the presence of Cl− using the PEC approach the degradation of B41 reaches 99.8%. High-performance liquid chromatography coupled with UV–VIS system confirmed the degradation of B41 dye using PEC. Gas-chromatography coupled to mass spectrometry was used to study the by-products obtained during PEC degradation. Chemical oxygen demand analyses confirmed that the mineralization level of B41 is in the order of 68%. The α-Fe2O3 films developed in this study give a higher level of PEC degradation efficiency compared to other iron oxide-based systems.
Keywords: thin films, photoelectrocatalysis, kinetics, visible light, degradation, textile dye
Published in RUNG: 10.05.2021; Views: 2242; Downloads: 12
URL Link to full text
This document has many files! More...

28.
Growth of MoSe2 electrocatalyst from metallic molybdenum nanoparticles for efficient hydrogen evolution : Growth of MoSe2 electrocatalyst from metallic molybdenum nanoparticles for efficient hydrogen evolution
Takwa Chouki, Boriana Donkova, Burhancan Aktarla, Plamen Stefanov, Saim Emin, 2021, original scientific article

Abstract: Molybdenum diselenide (MoSe2) is an emerging alternative to platinum-group-metal electrocatalysts for the hydrogen evolution reaction (HER). Herein, the chemical vapor deposition (CVD) approach was demonstrated to be a successful route to grow MoSe2 thin films using colloidal molybdenum nanoparticles (Mo NPs). T
Keywords: Water splitting, electrocatalyst, MoSe2
Published in RUNG: 15.01.2021; Views: 2249; Downloads: 0
This document has many files! More...

29.
Solvothermal synthesis of iron phosphides and their application for efficient electrocatalytic hydrogen evolution
Takwa Chouki, Manel Machreki, Saim Emin, 2020, original scientific article

Abstract: Abstract In this paper, we present a solvothermal synthesis of iron phosphide electrocatalysts using a triphenylphosphine (TPP) precursor. The synthetic protocol generates Fe2P phase at 300 °C and FeP phase at 350 °C. To enhance the catalytic activities of obtained iron phosphide particles heat-treatments were carried out at elevated temperatures. Annealing at 500 °C under reductive atmosphere induced structural changes in the samples: (i) Fe2P provided a pure Fe3P phase (Fe3P−500 °C) and (ii) FeP transformed into a mixture of iron phosphide phases (Fe2P/FeP−500 °C). Pure Fe2P films was prepared under argon atmosphere at 450 °C (Fe2P−450 °C). The electrocatalytic activities of heat-treated Fe2P−450 °C, Fe3P−500 °C, and Fe2P/FeP−500 °C catalysts were studied for hydrogen evolution reaction (HER) in 0.5 M H2SO4. The HER activities of the iron phosphide catalyst were found to be phase dependent. The lowest electrode potential of 110 mV vs. a reversible hydrogen electrode (RHE) at 10 mA cm−2 was achieved with Fe2P/FeP−500 °C catalyst.
Keywords: Solvothermal synthesis, Iron phosphide, Electrocatalyst, Hydrogen evolution, Overpotential
Published in RUNG: 20.07.2020; Views: 2612; Downloads: 0
This document has many files! More...

30.
Improved photocatalytic activity of anatase-rutile nanocomposites induced by low-temperature sol-gel Sn-modification of TiO2
Ksenija 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: 2947; Downloads: 0
This document has many files! More...

Search done in 0.07 sec.
Back to top