Dr. Virginija Kepeniene
Department of Catalysis, Center for Physical Sciences and Technology, Saulėtekio Ave. 3, Vilnius, Lithuania
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Academic Career Length
13Years (2014-Present)
(Calculated once Scilit publication data is synced: current year − year of first publication + 1)
Representative Publications
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Journal Article
Zita SukackieneGVGitana Valeckytė
Gitana ValeckytėVirginija KepenieneISIrena Stalnionienė
Irena StalnionienėVJVitalija Jasulaitienė
Vitalija JasulaitienėENEUGENIJUS NORKUS
EUGENIJUS NORKUS +3
The production of high-purity hydrogen from hydrogen storage materials with further direct use of generated hydrogen in fuel cells is still a relevant research field. For this purpose, nickel-molybdenum-plated copper catalysts (NiMo/Cu), comprising between 1 and 20 wt.% molybdenum, as catalytic materials for hydrogen generation, were prepared using a low-cost, straightforward electroless metal deposition method by using citrate plating baths containing Ni2+–Mo6+ ions as a metal source and morpholine borane as a reducing agent. The catalytic activity of the prepared NiMo/Cu catalysts toward alkaline sodium borohydride (NaBH4) hydrolysis increased with the increase in the content of molybdenum present in the catalysts. The hydrogen generation rate of 6.48 L min−1 gcat−1 was achieved by employing NiMo/Cu comprising 20 wt.% at a temperature of 343 K and a calculated activation energy of 60.49 kJ mol−1 with remarkable stability, retaining 94% of its initial catalytic activity for NaBH4 hydrolysis following the completion of the fifth cycle. The synergetic effect between nickel and molybdenum, in addition to the formation of solid-state solutions between metals, promoted the hydrogen generation reaction.
30 September 2020 in New Journal of Chemistry
Journal Article
Virginija KepenieneRSR. Stagniūnaitė
R. Stagniūnaitė
ABA. Balčiūnaitė
A. Balčiūnaitė
Loreta Tamasauskaite-TamasiunaiteENE. Norkus
E. Norkus
Deposition of AuNPs onto a CeO 2 /C substrate results in the enhanced electrocatalytic activity of the formed AuCeO 2 /C catalyst for the oxidation reaction of methanol, ethanol, ethylene glycol, and glycerol compared with the prepared Au/C catalyst.
Journal Article
Virginija KepenieneRSRaminta Stagniūnaitė
Raminta StagniūnaitėSRSidra Rafique
Sidra RafiqueJVJūratė Vaičiūnienė
Jūratė VaičiūnienėVJVitalija Jasulaitienė
Vitalija JasulaitienėENEUGENIJUS NORKUS
EUGENIJUS NORKUS +4
This paper describes the activity of PdCo3O4/C obtained by wet impregnation towards the oxygen reduction reaction (ORR). For this purpose, the Co3O4/C substrate was synthesized using the microwave irradiation heating method with further annealing of the substrate at 400 °C for 3 h (Co3O4/C-T). Then, the initial Co3O4/C substrate was impregnated with palladium chloride (Pd-Cl2-Co3O4/C), and then part of the obtained Pd-Cl2-Co3O4/C catalyst was annealed at 400 °C for 3 h (PdOCo3O4/C). The electrocatalytic activity of the prepared catalysts was investigated for the oxygen reduction reaction in alkaline media and compared with the commercial Pt/C (Tanaka wt. 46.6% Pt) catalyst. It was found that the annealed PdOCo3O4/C catalyst showed the largest ORR current density value of −11.27 mA cm−2 compared with Pd-Cl2-Co3O4/C (−7.39 mA cm−2) and commercial Pt/C (−5.25 mA cm−2).
Journal Article
Zita Sukackiene
Aldona BalčiūnaitėVirginija KepenieneJVJūratė Vaičiūnienė
Jūratė Vaičiūnienė
Giedrius StalnionisENEUGENIJUS NORKUS
EUGENIJUS NORKUS +2
In this study, cobalt-nickel (Co-Ni), cobalt-iron (Co-Fe), cobalt-iron-manganese (Co-Fe-Mn), cobalt-iron-molybdenum (Co-Fe-Mo), and cobalt-zinc (Co-Zn) coatings were studied as catalysts towards the evolution of hydrogen (HER) and oxygen (OER). The binary and ternary Co coatings were deposited on a copper surface using the electroless metal plating technique and morpholine borane (MB) as a reducing agent. The as-deposited Co-Ni, Co-Fe, Co-Fe-Mn, Co-Fe-Mo, and Co-Zn coatings produce compact and crack-free layers with typical globular morphology. It was found that the Co-Fe-Mo coating gives the lowest overpotential of 128.0 mV for the HER and the lowest overpotential of 455 mV for the OER to achieve a current density of 10 mA cm−2. The HER and OER current density values increase 1.4–2.0 times with an increase in temperature from 25 °C to 55 °C using the prepared 3D binary or ternary cobalt coatings for HER and OER. The highest mass electrocatalytic activity of 1.55 mA µg−1 for HER and 2.72 mA µg−1 for OER was achieved on the Co-Fe coating with a metal loading of 28.11 µg cm−2 at 25 °C.
24 November 2015 in ECS Transactions
Journal Article
MSMiroslav Semasko
Miroslav Semasko
Loreta Tamasauskaite-TamasiunaiteVirginija KepenieneAldona BalčiūnaitėJVJurate Vaiciuniene
Jurate Vaiciuniene
ENEugenijus Norkus
Eugenijus Norkus
+1
In this study a series of PtRuCo/GR with the different molar ratios were prepared by microwave-assisted heating of the reaction mixture consisting of H2PtCl6, RuCl3, CoCl2 and ethylene glycol. The Transmission Electron Microscopy and Inductively Coupled Plasma Optical Emission Spectroscopy were employed to characterize the synthesized PtRuCo/GR catalysts. The electrocatalytic activity of the synthesized catalysts towards the oxidation of methanol was investigated by means of cyclic voltammetry and chronoamperometry. It was found that the PtRuCo/GR catalysts with the Pt:Ru:Co molar ratios equal to 1:2:2, 1:1.7:5.6 and 3.5:1:23 were prepared. The PtRuCo/GR catalyst with the Pt:Ru:Co molar ratio equal to 3.5:1:23 has a higher electrocatalytic activity towards the oxidation of methanol in acidic medium as compared with that of other synthesized catalysts.
Journal Article
Zita SukackieneGVGitana Valeckytė
Gitana ValeckytėVirginija KepenieneISIrena Stalnionienė
Irena StalnionienėVJVitalija Jasulaitienė
Vitalija JasulaitienėENEUGENIJUS NORKUS
EUGENIJUS NORKUS +3
In this paper, the generation of hydrogen from alkaline sodium borohydride solution by hydrolysis is studied. To obtain catalysts for efficient hydrogen generation, Ni, Mn, Mo, and Co metals were deposited on the Cu surface by the simple electroless metal deposition method using morpholine borane as a reducing agent. Depending on the peculiarities of the deposition of each metal, the coating thickness was ca. 1 μm for all catalysts. The deposited coatings were compact and crack-free, with multilayer characteristics and a cauliflower-like structure. The prepared Ni/Cu, NiMn/Cu, NiMo/Cu, NiCo/Cu, NiCoMn/Cu, NiCoMo/Cu, and NiCoMoMn/Cu catalysts showed an efficient catalytic activity for sodium borohydride hydrolysis reaction. The lowest activation energy of 45.3 kJ mol−1 for sodium borohydride hydrolysis reaction was obtained using the NiCoMoMn/Cu catalyst. The highest hydrogen generation rate of 3.08 mL min−1 was also achieved using this catalyst at 303 K. With a further increase in temperature to 343 K, the hydrogen generation rate catalyzed by the NiCoMoMn/Cu increased 7.7 times and reached 23.57 mL min−1.
About Me
Dr. Virginija Kepenienė received her PhD degree in 2012 at the Department of Catalysis of the Center for Physical Sciences and Technology (FTMC) on electroless deposition in the group of Prof. dr. Eugenijus Norkus. After a post-doctoral internship related to the investigation of catalysts for alkaline fuel cells at the FTMC in the group of Dr. Loreta Tamašauskaitė-Tamašiūnaitė (2013-2015), she continued her work as a researcher in the same Department in relation to the synthesis and investigation of various nano-scale materials for fuel cell reactions. She has been working as a senior researcher since 2017. Virginija Kepenienė actively participates in scientific activity: she carries out experimental investigations; participates in projects as well as in student training; and supervises Bachelor’s, Master’s, and PhD work and student practice projects. She has published scientific articles in the ISI Web of Science database in referenced journals, has participated in international conferences, and has obtained several patents. Her research interests include electrocatalysis; microwave synthesis; carbon-based catalysts; fuel cells; water splitting; electrochemistry; and advanced multifunctional materials.