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Your search keyword '"Bele, Marjan"' showing total 231 results
Start Over Author "Bele, Marjan" Publication Type Academic Journals
231 results on '"Bele, Marjan"'

23. Ni-MoO 2 Composite Coatings Electrodeposited at Porous Ni Substrate as Efficient Alkaline Water Splitting Cathodes.

Author

Petričević, Aleksandar, Gojgić, Jelena, Bernäcker, Christian I., Rauscher, Thomas, Bele, Marjan, Smiljanić, Milutin, Hodnik, Nejc, Elezović, Nevenka, Jović, Vladimir D., and Krstajić Pajić, Mila N.

Subjects
HYDROGEN evolution reactions, ELECTRODE performance, COMPOSITE coating, SUBSTRATES (Materials science), WATER electrolysis
Abstract

To obtain highly efficient yet easily produced water-splitting cathodes, Ni-MoO2 composite coatings were electrodeposited at a Ni foam substrate with an open-pore structure, pore size of 450 µm, in a Watts-type bath. The concentration of MoO2 particles (about 100 nm) was varied, while the intensive mixing of the solution was provided by air bubbling with 0.5 L min−1. Electrodeposition was performed at different constant current densities at room temperature. The morphology and composition of the coatings were investigated by SEM and EDS. The hydrogen evolution reaction (HER) was tested in KOH of different concentrations, at several temperatures, in a three-electrode H-cell by recording polarization curves and EIS measurements. The lowest achieved HER overpotential was −158 mV at −0.5 A cm−2. Up-scaled samples, 3 × 3.3 cm2, were tested in a single zero-gap cell showing decreasing cell voltage (from 2.18 V to 2.11 V) at 0.5 A cm−2 over 5 h in 30% KOH at 70 °C with electrolyte flow rate of 58 mL min−1. Compared to pure Ni foams used as both cathode and anode under the same conditions, the cell voltage is decreased by 200 mV, showing improved electrode performance. [ABSTRACT FROM AUTHOR]

Published
2024
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36. Time and Potential‐Resolved Comparison of Copper Disc and Copper Nanoparticles for Electrocatalytic Hydrogenation of Furfural.

Author

Maselj, Nik, Jovanovski, Vasko, Ruiz-Zepeda, Francisco, Finšgar, Matjaž, Klemenčič, Tamara, Trputec, Jan, Kamšek, Ana Rebeka, Bele, Marjan, Hodnik, Nejc, and Jovanovič, Primož

Subjects
FURFURAL, HYDROGENATION, COPPER, NANOPARTICLES, FURFURYL alcohol, HYDROGEN evolution reactions, TIME-resolved spectroscopy
Abstract

Herein, a comparative analysis of two case example catalysts for electrocatalytic hydrogenation (ECH) of furfural under acidic conditions, namely a copper polycrystalline disc and copper nanoparticles dispersed on carbon support, is performed. To gain a detailed insight on ECH trends, a task‐specific methodology is employed based on electrochemistry–mass spectrometry coupling, which enabled time‐ and potential‐resolved detection of volatile ECH products, i.e., 2‐methylfurane (2‐MF) and H2. In this way, the ability to elucidate potential‐dependent product distribution for the two catalysts, namely faradaic efficiency, is achieved. Accordingly, the nanoparticulate analog is significantly more active toward competitive hydrogen evolution reaction and 2‐MF production, whereas the polycrystalline sample is more selective toward furfuryl alcohol. The observed differences in ECH are ascribed to alterations in surface domains, which is supported by surface‐sensitive lead underpotential deposition characterization. [ABSTRACT FROM AUTHOR]

Published
2023
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37. Mechanistic Study of Fast Performance Decay of PtCu Alloy-based Catalyst Layers for Polymer Electrolyte Fuel Cells through Electrochemical Impedance Spectroscopy.

Author

Grandi, Maximilian, Gatalo, Matija, Kamšek, Ana Rebeka, Kapun, Gregor, Mayer, Kurt, Ruiz-Zepeda, Francisco, Šala, Martin, Marius, Bernhard, Bele, Marjan, Hodnik, Nejc, Bodner, Merit, Gaberšček, Miran, and Hacker, Viktor

Subjects
ELECTRIC batteries, IMPEDANCE spectroscopy, POLYELECTROLYTES, PROTON exchange membrane fuel cells, ROTATING disk electrodes, PLATINUM catalysts, CATALYSTS, OXYGEN reduction
Abstract

In the past, platinum–copper catalysts have proven to be highly active for the oxygen reduction reaction (ORR), but transferring the high activities measured in thin-film rotating disk electrodes (TF-RDEs) to high-performing membrane electrode assemblies (MEAs) has proven difficult due to stability issues during operation. High initial performance can be achieved. However, fast performance decay on a timescale of 24 h is induced by repeated voltage load steps with H2/air supplied. This performance decay is accelerated if high relative humidity (>60% RH) is set for a prolonged time and low voltages are applied during polarization. The reasons and possible solutions for this issue have been investigated by means of electrochemical impedance spectroscopy and distribution of relaxation time analysis (EIS–DRT). The affected electrochemical sub-processes have been identified by comparing the PtCu electrocatalyst with commercial Pt/C benchmark materials in homemade catalyst-coated membranes (CCMs). The proton transport resistance (Rpt) increased by a factor of ~2 compared to the benchmark materials. These results provide important insight into the challenges encountered with the de-alloyed PtCu/KB electrocatalyst during cell break-in and operation. This provides a basis for improvements in the catalysts' design and break-in procedures for the highly attractive PtCu/KB catalyst system. [ABSTRACT FROM AUTHOR]

Published
2023
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40. Corrigendum to “Observing, tracking and analysing electrochemically induced atomic-scale structural changes of an individual Pt-Co nanoparticle as a fuel cell electrocatalyst by combining modified floating electrode and identical location electron microscopy” [Electrochimica Acta 388 (2021) 138513]

Author

Hrnjic, Armin, Kamšek, Ana Rebeka, Pavlišič, Andraž, Šala, Martin, Bele, Marjan, Moriau, Leonard, Gatalo, Matija, Ruiz-Zepeda, Francisco, Jovanovič, Primož, and Hodnik, Nejc

Published
2022
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46. Alternative and facile production pathway towards obtaining high surface area PtCo/C intermetallic catalysts for improved PEM fuel cell performance.

Author

Heizmann, Philipp A., Nguyen, Hien, von Holst, Miriam, Fischbach, Andreas, Kostelec, Mitja, Gonzalez Lopez, Francisco Javier, Bele, Marjan, Pavko, Luka, Đukić, Tina, Šala, Martin, Ruiz-Zepeda, Francisco, Klose, Carolin, Gatalo, Matija, Hodnik, Nejc, Vierrath, Severin, and Breitwieser, Matthias

Published
2023
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