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149 results on '"Tsyntsarski, Boyko"'

3. Porous Structure and Surface Chemistry of Biomorphous Composite Derived from Carbonized Yucca Covered by Thin Film of Chitosan and Its Application to Remove Hazardous Substances

Author

Majewska, Justyna, Krzesińska, Marta, Budinova, Temenuzhka, Filipowska, Anna, Petrov, Nartzislav, Tsyntsarski, Boyko, Kacprzyk, Janusz, Series Editor, Gomide, Fernando, Advisory Editor, Kaynak, Okyay, Advisory Editor, Liu, Derong, Advisory Editor, Pedrycz, Witold, Advisory Editor, Polycarpou, Marios M., Advisory Editor, Rudas, Imre J., Advisory Editor, Wang, Jun, Advisory Editor, Gzik, Marek, editor, Paszenda, Zbigniew, editor, Piętka, Ewa, editor, Tkacz, Ewaryst, editor, Milewski, Krzysztof, editor, and Jurkojć, Jacek, editor

Published
2023
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8. Correction to: Porous Structure and Surface Chemistry of Biomorphous Composite Derived from Carbonized Yucca Covered by Thin Film of Chitosan and Its Application to Remove Hazardous Substances

Author

Majewska, Justyna, Krzesińska, Marta, Budinova, Temenuzhka, Filipowska, Anna, Petrov, Nartzislav, Tsyntsarski, Boyko, Kacprzyk, Janusz, Series Editor, Gomide, Fernando, Advisory Editor, Kaynak, Okyay, Advisory Editor, Liu, Derong, Advisory Editor, Pedrycz, Witold, Advisory Editor, Polycarpou, Marios M., Advisory Editor, Rudas, Imre J., Advisory Editor, Wang, Jun, Advisory Editor, Gzik, Marek, editor, Paszenda, Zbigniew, editor, Piętka, Ewa, editor, Tkacz, Ewaryst, editor, Milewski, Krzysztof, editor, and Jurkojć, Jacek, editor

Published
2023
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14. Investigation of the Influence of Ionization Radiation on Glassy Carbon Coatings, after Long Stay in the Outer Space on the International Space Station (ISS)

Author

Teodosiev, Dimitar, primary, Bouzekova-Penkova, Anna, additional, Koleva, Rositsa, additional, Tonev, Dimitar, additional, Geleva, Elena, additional, Tsyntsarski, Boyko, additional, Tzvetkov, Peter, additional, Goutev, Nikolay, additional, Demerdjiev, Anguel, additional, and Slavchev, Bozhidar, additional

Published
2023
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18. CoFe-loaded P, N co-doped carbon foam derived from petroleum pitch waste: An efficient electrocatalyst for oxygen evolution reaction

Author

European Commission, Gebreslase, Gebrehiwet Abrham [0000-0003-3151-6694], Sebastián del Río, David [0000-0002-7722-2993], Martínez Huerta, M. Victoria [0000-0002-2644-0982], Tsoncheva, T. [0000-0002-8202-9012], Tsyntsarski, Boyko [0000-0002-7014-366X], Lázaro Elorri, María Jesús [0000-0002-4769-2564], Gebreslase, Gebrehiwet Abrham, Sebastián del Río, David, Martínez Huerta, M. Victoria, Tsoncheva, T., Tsyntsarski, Boyko, Georgiev, Georgi, Lázaro Elorri, María Jesús, European Commission, Gebreslase, Gebrehiwet Abrham [0000-0003-3151-6694], Sebastián del Río, David [0000-0002-7722-2993], Martínez Huerta, M. Victoria [0000-0002-2644-0982], Tsoncheva, T. [0000-0002-8202-9012], Tsyntsarski, Boyko [0000-0002-7014-366X], Lázaro Elorri, María Jesús [0000-0002-4769-2564], Gebreslase, Gebrehiwet Abrham, Sebastián del Río, David, Martínez Huerta, M. Victoria, Tsoncheva, T., Tsyntsarski, Boyko, Georgiev, Georgi, and Lázaro Elorri, María Jesús

Abstract

Designing and developing affordable, high-performance, and stable electrocatalysts for oxygen evolution reaction (OER) is decisive for pragmatic water electrolysis to produce green hydrogen energy. In this work, we report cobalt and iron incorporated in phosphorus and nitrogen co-doped carbon foam (CF) derived from petroleum pitch as a promising electrocatalyst for alkaline OER. The P, N heteroatoms co-doped carbon foam (PN-CF) was first synthesized via thermo-chemical treatment of low-cost petroleum pitch in the presence of melamine (N source) and sodium hypophosphite (P source) precursors, followed by carbonization. Then, mono and bimetals of Co and Fe were impregnated into the as-prepared composite carbon foam (PN-CF) substrate, followed by further carbonization. Among the different catalysts, the bimetallic CoFe integrated with the PN-CF (CoFe@PN-CF) reveals an outstanding electrocatalytic activity (320 mV overpotential at j = 10 mA·cm-2), low Tafel slope (48 mV·dec-1), and excellent durability during OER measurement in 1 M KOH aqueous solution. The superb performance of the CoFe@PN-CF catalyst stems from the synergetic effect of the bimetals confined on phosphorus and nitrogen co-doped carbon foam support with high specific surface area, highly porous structure, and formation of graphitic domains, which enhances the electrical conductivity. This work sheds light on the potential for valorizing petroleum pitch and provides a facile synthesis approach to synthesizing a low-cost, high-performance, and durable electrocatalyst for alkaline OER.

Published
2022

19. Mesoporous Ce-Fe-Ni nanocomposites encapsulated in carbon-nanofibers: Synthesis, characterization and catalytic behavior in oxygen evolution reaction

Author

European Commission, Rosmini, Consolato [0000-0003-2292-6376], Tsoncheva, T. [0000-0002-8202-9012], Kolev, Hristo [0000-0002-4231-9306], Karashanova, Daniela [0000-0002-8785-3190], Tsyntsarski, Boyko [0000-0002-7014-366X], Sebastián del Río, David [0000-0002-7722-2993], Lázaro Elorri, María Jesús [0000-0002-4769-2564], Rosmini, Consolato, Tsoncheva, T., Kovatcheva, Daniela, Velinov, Nikolay, Kolev, Hristo, Karashanova, Daniela, Dimitrov, M., Tsyntsarski, Boyko, Sebastián del Río, David, Lázaro Elorri, María Jesús, European Commission, Rosmini, Consolato [0000-0003-2292-6376], Tsoncheva, T. [0000-0002-8202-9012], Kolev, Hristo [0000-0002-4231-9306], Karashanova, Daniela [0000-0002-8785-3190], Tsyntsarski, Boyko [0000-0002-7014-366X], Sebastián del Río, David [0000-0002-7722-2993], Lázaro Elorri, María Jesús [0000-0002-4769-2564], Rosmini, Consolato, Tsoncheva, T., Kovatcheva, Daniela, Velinov, Nikolay, Kolev, Hristo, Karashanova, Daniela, Dimitrov, M., Tsyntsarski, Boyko, Sebastián del Río, David, and Lázaro Elorri, María Jesús

Abstract

Ceria-iron oxide mesoporous materials with Fe:Ce molar ratio of 5:5 and 9:1 were synthesized by hydrothermal method using CTAB as a template and subsequently modified with NiO (molar ratio Ni:Fe = 1:2) by incipient wetness impregnation technique. In order to increase the electro-capacitive properties and reduce the intrinsic impedance of the metal oxides, the samples were consecutively modified by reduction in hydrogen to obtain highly dispersed Ni–Fe alloys into ceria matrix. By exploiting the high permeability of carbon inside ferrous alloys, the metal phase has been further modified into ferrous carbides and metal alloys encapsulated within carbon nanofibers. For this purpose, a reaction, already widely studied for the production of hydrogen, was used, that is the decomposition of methanol vapors. In fact, this decomposition, in addition to producing syn-gas and methane, changes the catalysts in use through a chemical vapor deposition-carbon coating process. This fact, has been used by us to demonstrate how the newly obtained metal-carbon nanocomposites can be used for electro-catalytic purposes. The modified phases of the two molar ratios of the Fe–Ni–Ce catalysts were tested in the Oxygen Evolution Reaction (OER) in an alkaline environment (1 M KOH), showing a satisfactory and progressive increase in activity and a surprising decrease in the overpotential at 10 mA/cm2 of current density. The morphological, textural and physicochemical properties of the samples were characterized in details by XRD, N2-physisorption, TG-TPO, TEM, EDX, FTIR, XPS, Raman and Moessbauer spectroscopies.

Published
2022

22. CoFe-loaded P, N co-doped carbon foam derived from petroleum pitch waste: An efficient electrocatalyst for oxygen evolution reaction

Author

Gebreslase, Gebrehiwet Abrham, Sebastián del Río, David, Martínez Huerta, M.ª Victoria, Tsoncheva, T., Tsyntsarski, Boyko, Georgiev, Georgi, Lázaro Elorri, María Jesús, European Commission, Gebreslase, Gebrehiwet Abrham, Sebastián del Río, David, Martínez Huerta, M.ª Victoria, Tsoncheva, T., Tsyntsarski, Boyko, and Lázaro Elorri, María Jesús

Subjects
N co-doped carbon foam, Oxygen evolution reaction, Carbon foam, CoFe, Electrocatalysts, General Chemistry, And P, Petroleum pitch, Catalysis
Abstract

13 figures, 4 tables.-- Supplementary material available., Designing and developing affordable, high-performance, and stable electrocatalysts for oxygen evolution reaction (OER) is decisive for pragmatic water electrolysis to produce green hydrogen energy. In this work, we report cobalt and iron incorporated in phosphorus and nitrogen co-doped carbon foam (CF) derived from petroleum pitch as a promising electrocatalyst for alkaline OER. The P, N heteroatoms co-doped carbon foam (PN-CF) was first synthesized via thermo-chemical treatment of low-cost petroleum pitch in the presence of melamine (N source) and sodium hypophosphite (P source) precursors, followed by carbonization. Then, mono and bimetals of Co and Fe were impregnated into the as-prepared composite carbon foam (PN-CF) substrate, followed by further carbonization. Among the different catalysts, the bimetallic CoFe integrated with the PN-CF (CoFe@PN-CF) reveals an outstanding electrocatalytic activity (320 mV overpotential at j = 10 mA·cm-2), low Tafel slope (48 mV·dec-1), and excellent durability during OER measurement in 1 M KOH aqueous solution. The superb performance of the CoFe@PN-CF catalyst stems from the synergetic effect of the bimetals confined on phosphorus and nitrogen co-doped carbon foam support with high specific surface area, highly porous structure, and formation of graphitic domains, which enhances the electrical conductivity. This work sheds light on the potential for valorizing petroleum pitch and provides a facile synthesis approach to synthesizing a low-cost, high-performance, and durable electrocatalyst for alkaline OER., Financial support from the European Union's Horizon 2020 Research and Innovation programme under the Marie Skłodowska-Curie Actions−Innovative Training Networks (MSCA-ITN) Grant Agreement 813748 are gratefully acknowledged.

Published
2022
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23. XPS INVESTIGATION OF THE WORK FUNCTION OF GLASSY CARBON COATINGS AFTER EXTENDED STAY ON THE INTERNATIONAL SPACE STATION (ISS).

Author

Tsanev, Aleksandar, Grigorov, Korneli, Kolev, Hristo, Bouzekova-Penkova, Anna, Tsyntsarski, Boyko, Tsvetkov, Peter, and Teodosiev, Dimitar

Subjects
ELECTRON work function, SPACE stations, CARBON nanofibers, SURFACE coatings, SPACE plasmas, ELECTRIC fields
Abstract

Copyright of Aerospace Research in Bulgaria is the property of Bulgarian Academy of Sciences, Space Research & Technology Institute (SRTI-BAS) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Published
2024
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27. Hydrogen Storage Properties of Ball Milled MgH 2 with Additives- Ni, V and Activated Carbons Obtained from Different By-Products.

Author

Grigorova, Eli, Markov, Pavel, Tsyntsarski, Boyko, Tzvetkov, Peter, and Stoycheva, Ivanka

Subjects
HYDROGEN storage, ACTIVATED carbon, BALL mills, CARBON-based materials, X-ray diffraction, WASTE products
Abstract

The hydrogen sorption of materials based on 80 wt.% MgH2 with the addition of 15 wt.% Ni or V and 5 wt.% activated carbons synthesized from polyolefin wax, a waste product from polyethylene production (POW), walnut shells (CAN), and peach stones (CPS) prepared by milling under an inert Ar atmosphere for a period of 1 h, is investigated. All precursors are submitted to pyrolysis followed by steam activation in order to obtain the activated carbons. The hydrogen sorption evaluations are carried out for absorption at 473 and 573 K with pressure of 1 MPa and for desorption at 623 and 573 K with pressure of 0.15 MPa. The composition of the samples after milling and hydrogenation is monitored by X-ray diffraction analyses. The 80 wt.% MgH2–15 wt. %Ni–5 wt.% POW or CAN after absorption–desorption cycling and in a hydrogenated state at 573 K and 1 MPa are analyzed by TEM. [ABSTRACT FROM AUTHOR]

Published
2023
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39. Mesoporous Ce-Fe-Ni Nanocomposites Encapsulated in Carbon-Nanofibers: Synthesis, Characterization and Catalytic Behavior in Oxygen Evolution Reaction

Author

Rosmini, Consolato, primary, Tsoncheva, Tanya, additional, Kovatcheva, Daniela, additional, Velinov, Nikolay, additional, Kolev, Hristo, additional, Karashanova, Daniela, additional, Dimitrov, Momtchil, additional, Tsyntsarski, Boyko, additional, Sebastián, David, additional, and Lázaro, María Jesús, additional

Published
2022
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46. BIOCARBON FROM DIFFERENT BIOMASS PRECURSORS

Author

Miteva, Kalina, primary, Georgiev, Georgi, additional, Stoycheva, Ivanka, additional, Petrov, Nartzislav, additional, Petrova, Bilyana, additional, Sarbu, Andrei, additional, and Tsyntsarski, Boyko, additional

Published
2021
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50. NOVEL SYNTHESIS METHOD OF CARBON MATERIALS FROM REFUSEDERIVED FUEL.

Author

Georgiev, Georgi, Stoycheva, Ivanka, Tsyntsarski, Boyko, Miteva, Kalina, and Yardim, Mehmet Ferhat

Subjects
REFUSE as fuel, INDUSTRIAL wastes, CARBON composites, ACTIVATION (Chemistry), WASTE recycling, MICROBIOLOGICAL aerosols, FUEL additives, VIRUS removal (Water purification)
Abstract

RDF (Refuse Derived Fuel) is obtained from the highly combustible components of household and industrial waste. RDF is mainly used in European countries with a high standard for waste recycling, such as Austria, Germany and the Netherlands. A method for the synthesis of carbon materials and composites based on RDF, coal pitch, petroleum coke and others has been developed. Some of the used components of RDF are: cardboard, polyethylene and polypropylene. The first step in the synthesis process is oxidation, performed at a temperature of 300oC and addition of oxidizer. Then the finished samples are carbonized at 550-750 oC, the last stage of the synthesis is activation: hydropyrolysis at 600-900 oC, physical activation with CO2 or chemical activation. The obtained samples are characterized by BET, SEM, XRD, elemental analysis and others. The final products have high surface area. The characteristics of the obtained carbon materials determine their possible application for adsorption of pollutants and nanoparticles used to neutralize microorganisms (bacteria and viruses) in water and air. [ABSTRACT FROM AUTHOR]

Published
2021
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