1. Solvothermal synthesis of iron phosphides and their application for efficient electrocatalytic hydrogen evolutionSaim 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: ključnih besedah
Summary of found: ...we present a solvothermal synthesis of iron phosphide electrocatalysts using a triphenylphosphine (TPP) precursor. The...
Keywords: Solvothermal synthesis, Iron phosphide, Electrocatalyst, Hydrogen evolution, Overpotential
Published: 20.07.2020; Views: 1848; Downloads: 0
 Fulltext (2,52 MB) |
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3. Solvothermal synthesis of iron phosphides and their application for efficient electrocatalytic hydrogen evolutionSaim 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: ključnih besedah
Summary of found: ...We report the solvothermal synthesis of iron phosphide electrocatalysts using a low-cost phosphorus precursor [1]....
Keywords: solvothermal synthesis, iron phosphide, electrocatalyst, hydrogen evolution, overpotential
Published: 13.05.2021; Views: 1368; Downloads: 0
Fulltext (4,08 MB) |
4. Highly active iron phosphide catalysts for selective electrochemical nitrate reduction to ammoniaSaim Emin, Luis Miguel Azofra, Moussab Harb, Georgi Tyuliev, Pawel J. Kulesza, Iwona Rutkowska, Beata Rytelewska, Manel Machreki, Takwa Chouki, 2023, original scientific article Abstract: The electrochemical reduction reaction of the nitrate ion (NO3−), a widespread water pollutant, to valuable ammonia (NH3) is a promising approach for environmental remediation and green energy conservation. The development of high-performance electrocatalysts to selectively reduce NO3− wastes into value-added NH3 will open up a different route of NO3− treatment, and impose both environmental and economic impacts on sustainable NH3 synthesis. Transition metal phosphides represent one of the most promising earth-abundant catalysts with impressive electrocatalytic activities. Herein, we report for the first time the electrocatalytic reduction of NO3− using different phases of iron phosphide. Particularly, FeP and Fe2P phases were successfully demonstrated as efficient catalysts for NH3 generation. Detection of the in-situ formed product was achieved using electrooxidation of NH3 to nitrogen (N2) on a Pt electrode. The Fe2P catalyst exhibits the highest Faradaic efficiency (96 %) for NH3 generation with a yield (0.25 mmol h−1 cm-−2 or 2.10 mg h−1 cm−2) at − 0.55 V vs. reversible hydrogen electrode (RHE). The recycling tests confirmed that Fe2P and FeP catalysts exhibit excellent stability during the NO3− reduction at − 0.37 V vs. RHE. To get relevant information about the reaction mechanisms and the fundamental origins behind the better performance of Fe2P, density functional theory (DFT) calculations were performed. These results indicate that the Fe2P phase exhibits excellent performance to be deployed as an efficient noble metal-free catalyst for NH3 generation.
Found in: ključnih besedah
Keywords: Iron phosphide, Electrocatalysts, Nitrates reduction Ammonia, DFT calculations
Published: 02.02.2023; Views: 335; Downloads: 0
Fulltext (7,95 MB) |
5. Efficient Iron Phosphide Catalyst as a Counter Electrode in Dye-Sensitized Solar CellsSammy W Verbruggen, Rajeshreddy Ninakanti, Saim Emin, Aycan Atli, Moussab Harb, Takwa Chouki, Abdullah Yildiz, 2021, original scientific article Abstract: Developing an efficient material as a counter electrode (CE) with excellent catalytic activity, intrinsic stability, and low cost is essential for the commercial application of dye-sensitized solar cells (DSSCs). Transition metal phosphides have been demonstrated as outstanding multifunctional catalysts in a broad range of energy conversion technologies. Here, we exploited different phases of iron phosphide as CEs in DSSCs with an I–/I3–-based electrolyte. Solvothermal synthesis using a triphenylphosphine precursor as a phosphorus source allows to grow a Fe2P phase at 300 °C and a FeP phase at 350 °C. The obtained iron phosphide catalysts were coated on fluorine-doped tin oxide substrates and heat-treated at 450 °C under an inert gas atmosphere. The solar-to-current conversion efficiency of the solar cells assembled with the Fe2P material reached 3.96 ± 0.06%, which is comparable to the device assembled with a platinum (Pt) CE. DFT calculations support the experimental observations and explain the fundamental origin behind the improved performance of Fe2P compared to FeP. These results indicate that the Fe2P catalyst exhibits excellent performance along with desired stability to be deployed as an efficient Pt-free alternative in DSSCs.
Found in: ključnih besedah
Keywords: Iron phosphide, catalyst, counter electrode, dye-sensitized solar cell, solvothermal synthesis
Published: 06.02.2023; Views: 258; Downloads: 0
Fulltext (4,96 MB) |
6. Iron phosphide as an efficient electrocatalysts for hydrogen evolutionSaim 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. 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 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 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: ključnih besedah
Keywords: solvothermal synthesis
iron phosphide
electrocatalysis
HER
Published: 06.02.2023; Views: 276; Downloads: 0
Fulltext (2,67 MB) |
7. Iron phosphide thin films for electrocatalytic H2 generation and water remediation studiesSaim Emin, Aaron Fait, Matjaz Valant, Jack S Summers, Erika Jez, Plamen Stefanov, Lorena Butinar, Jelena Topic, Takwa Chouki, Manel Machreki, 2022, published scientific conference contribution abstract Found in: ključnih besedah
Keywords: Iron phosphide thin films
H2 generation
water remediation
Published: 10.02.2023; Views: 282; Downloads: 0
Fulltext (755,86 KB) |
