Publications by authors named "Petros M Sakkas"

4 Publications

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Rhenium oxide nanoparticles - Sonochemical synthesis and integration on anode powders for solid oxide fuel cells.

Ultrason Sonochem 2020 Dec 8;69:105250. Epub 2020 Jul 8.

National Technical University of Athens, School of Chemical Engineering, Laboratory of Inorganic Materials Technology, I. Polytechniou 9, 15773 Zografou, Athens, Greece; Technische Universität Clausthal, Clausthal Research Center for Materials Technology (CZM), Leibnizstr. 9, 38678 Clausthal-Zellerfeld, Germany. Electronic address:

Rhenium oxide nanoparticles have been prepared using ultrasonication at 20 kHz. Samples characterization was committed via SEM-EDX, TEM, XRD, and Raman spectroscopy. Various experimental parameters were examined, including precursor/substrate amounts, ultrasonication intensity, and type of solvent used. Insights to the agglomeration of the prepared nanoparticles depending on the preparation parameters are given. As ultrasonic source we used either an ultrasonic probe by Sonics & Materials Inc. (20 kHz, 750 W net output) or a Bandelin SONOPULS HD 3200 ultrasound generator (20 kHz, 200 W net output) at intensities between 30 and 100 W/cm. The rhenium oxide nanoparticles haven been decorated on state-of-the-art anode materials (NiO/GDC) for solid oxide fuel cells (SOFCs) in order to prepare catalytically more active anode powders. These experiments revealed that ultrasonication intensity and solvents used are able to affect final nanoparticles size distribution and morphology. At the same time, ratio of precursor and substrate compounds amounts as well as ultrasonication intensity and duration were all found to affect the decoration loading extend of nanoformations on substrate powders. The results showing the influence of the above-mentioned parameters allowed for the quantification of the effects on the loading and the preferable sites of the decoration.
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http://dx.doi.org/10.1016/j.ultsonch.2020.105250DOI Listing
December 2020

A study on the synchronous decoration of molybdenum oxide or tungsten oxide nanoparticles on anode materials for natural gas fed solid oxide fuel cells using ultrasounds.

Ultrason Sonochem 2019 Dec 1;59:104715. Epub 2019 Aug 1.

National Technical University of Athens, School of Chemical Engineering, Laboratory of Inorganic Materials Technology, I. Polytechniou 9, 15773 Zografou/Athens, Greece; Technische Universität Clausthal, Clausthal Research Centre for Materials Technology (CZM), Leibnizstr. 9, 38678 Clausthal-Zellerfeld, Germany. Electronic address:

Sonochemistry was used for the metal oxides nanoparticle synthesis. All experiments were run using a BANDELIN Sonopuls HD 3200 ultrasonic generator (20 kHz, 200 W net output) with a ultrasonic probe in thermostated environment of 80 °C under ambient air. At the same time, ultrasonication activity achieved their decoration on state-of-the-art fuel cell anode powders. These modified powders shall be used in solid oxide and ceramic proton exchange membrane fuel cells anode sites. Metal oxide nanoformations synthesized were those of tungsten and molybdenum. In case of sonochemical synthesis, organometallic compounds dissolved in organic solvents played the role of precursors. Experiments of metal oxides synthesis revealed that ultrasonication intensity and solvents are able to affect final nanoparticles size distribution and morphology. At the same time, ratio of precursor and substrate compounds amounts as well as ultrasonication intensity and duration were all found to affect the decoration loading extent of nanoformations on substrates. Transmission electron microscopy was mainly used for identifying the final product of each synthesis attempt. Moreover, selected area diffraction of characteristic formations examined, gave important information about the nanocrystallinity and stoichiometry of all materials synthesized.
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http://dx.doi.org/10.1016/j.ultsonch.2019.104715DOI Listing
December 2019

Sonoelectrochemical one-pot synthesis of Pt - Carbon black nanocomposite PEMFC electrocatalyst.

Ultrason Sonochem 2017 Mar 13;35(Pt B):591-597. Epub 2016 May 13.

National Technical University of Athens, School of Chemical Engineering, Zografou Campus, 9 Heroon Polytechneiou St., 15773 Zografou-Athens, Greece; Institut für Energieforschung und Physikalische Technologien, Clausthal University of Technology, Leibnizstr. 4, 38678 Clausthal-Zell., Germany; Clausthaler Zentrum für Materialforschung (CZM), Agricola Str. 2, 38678 Clausthal-Zellerfeld, Germany. Electronic address:

Simultaneous electrocatalytic Pt-nanoparticle synthesis and decoration of Vulcan XC-72 carbon black substrate was achieved in a novel one-step-process, combining galvanostatic pulsed electrodeposition and pulsed ultrasonication with high power, low-frequency (20kHz) ultrasound. Aqueous chloroplatinic acid precursor baths, as well as carbon black suspensions in the former, were examined and decoration was proven by a combination of characterization methods, namely: dynamic light scattering, transmission electron microscopy, scanning electron microscopy with EDX-analysis and cyclic voltammetry. In particular, PVP was shown to have a beneficial stabilizing effect against free nanoparticle aggregation, ensuring narrow size distributions of the nanoparticles synthesized, but is also postulated to prevent the establishment of a strong metal-substrate interaction. Current pulse amplitude was identified as the most critical nanoparticle size-determining parameters, while only small size particles, under 10nm, appeared to be attached to carbon black.
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http://dx.doi.org/10.1016/j.ultsonch.2016.05.023DOI Listing
March 2017

Sonochemistry in the service of SOFC research.

Ultrason Sonochem 2014 Nov 8;21(6):1939-47. Epub 2014 Feb 8.

School of Chemical Engineering, National Technical University of Athens, 15780 Zografou Campus, Greece. Electronic address:

Decoration of SOFC anode cermets with metal nanoparticles (NPs) enchance their ability and stability in natural gas to hydrogen reform. A novel sonoelectrochemical approach of Au-NPs synthesis (mean 12.31±2.69nm) is suggested, according to which the sonication is held constant while the electrochemical activity is either pulsed or continuous. The gold colloidal solution is cosonicated with state of the art cermet powder to yield particles decorated with Au-NPs. Nevertheless sonochemical routes of mixed molybdenum, rhenium or tungsten mixed oxides synthesis are utilized in order to decorate SOFC anode cermets. The decoration loading achieved spanned from 0.1 to 10.0wt.%.
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http://dx.doi.org/10.1016/j.ultsonch.2014.02.001DOI Listing
November 2014
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