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1.
Solvothermal synthesis of iron phosphides and their application for efficient electrocatalytic hydrogen evolution
Saim Emin, Takwa Chouki, Manel Machreki, 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.
Found in: osebi
Keywords: Solvothermal synthesis, Iron phosphide, Electrocatalyst, Hydrogen evolution, Overpotential
Published: 20.07.2020; Views: 916; Downloads: 0
.pdf Fulltext (2,52 MB)

2.
Preparation of porous [alpha]-Fe[sub]2O[sub]3 thin films for efficient photoelectrocatalytic degradation of basic blue 41 dye
Saim Emin, Lorena Butinar, Branka Mozetič Vodopivec, Mitja Martelanc, Manel Machreki, Takwa Chouki, 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.
Found in: osebi
Keywords: thin films, photoelectrocatalysis, kinetics, visible light, degradation, textile dye
Published: 10.05.2021; Views: 427; Downloads: 2
URL Fulltext (0,00 KB)
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3.
Solvothermal synthesis of iron phosphides and their application for efficient electrocatalytic hydrogen evolution
Saim Emin, Manel Machreki, Takwa Chouki, 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.
Found in: osebi
Keywords: solvothermal synthesis, iron phosphide, electrocatalyst, hydrogen evolution, overpotential
Published: 13.05.2021; Views: 424; Downloads: 0
.pdf Fulltext (4,08 MB)

4.
Photoelectrocatalytic water splitting and dye degradation with fluorine doped tin oxides films
Saim Emin, Takwa Chouki, Manel Machreki, 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.
Found in: osebi
Keywords: FTO, thin films, dye degradation
Published: 13.05.2021; Views: 380; Downloads: 0
.pdf Fulltext (3,87 MB)

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