Browsing Τμήμα Χημείας / Department of Chemistry by Author "Polychronopoulou, Kyriaki"
Now showing items 1-18 of 18
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Absorption-enhanced reforming of phenol by steam over supported Fe catalysts
Polychronopoulou, Kyriaki; Bakandritsos, Aristides; Tzitzios, Vasileios; Fierro, José Luis García; Efstathiou, Angelos M. (2006)Supported Fe catalysts of varying support chemical composition prepared by sol-gel and incipient wetness impregnation methods were studied for the steam reforming of phenol (one of the main constituents of tar produced ...
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Article
Ceria-based materials for hydrogen production via hydrocarbon steam reforming and water-gas shift reactions
Polychronopoulou, Kyriaki; Kalamaras, Christos M.; Efstathiou, Angelos M. (2011)This review paper provides an overview of the use of ceria-based catalytic materials towards the industrial hydrogen production via the hydrocarbon steam reforming and the water-gas shift reaction routes with a focus on ...
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Article
Cu-Ce-La-Ox as efficient CO oxidation catalysts: Effect of Cu content
AlKetbi, Maitha; Polychronopoulou, Kyriaki; Abi Jaoude, Maguy; Vasiliades, Michalis A.; Sebastian, Victor; Hinder, Steven J.; Baker, Mark A.; Zedan, Abdallah F.; Efstathiou, Angelos M. (2020)Nanograins of Ce-La-xCu-O mixed metal oxides (wherex = 3, 5, 7, 10, 20 at.%), of approximately 16 nm2 area size, and having all the metal cations homogeneously distributed, are tested as ternary catalytic materials towards ...
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Article
Effect of humic acid on the solid phase stability of UO2CO 3
Antoniou, Stella; Kolokassidou, C.; Polychronopoulou, Kyriaki; Pashalidis, Ioannis (2009)The stability of UO2CO3 has been studied as a function of the humic acid concentration in 0.1M NaClO4, in the weak acidic pH range (4.5-5) under CO2 atmosphere. The solid phase under investigation has been prepared by ...
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Article
Effects of sol-gel synthesis on 5Fe-15Mn-40Zn-40Ti-O mixed oxide structure and its H2S removal efficiency from industrial gas streams
Polychronopoulou, Kyriaki; Efstathiou, Angelos M. (2009)A novel Fe-Mn-Zn-Ti-O mixed metal oxide has been developed for efficient low-temperature (25-50°C) removal of H2S from a gas mixture containing 600 ppm H2S, 25 vol% H2, 7.5 vol % CO 2, and 1-3 vol% H2O that simulates typical ...
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Article
An investigation of the NO/H2/O2 (Lean De-NOx) reaction on a highly active and selective Pt/La0.7Sr0.2Ce0.1FeO3 catalyst at low temperatures
Costa, Costas N.; Savva, Petros G.; Andronikou, Ch; Lambrou, Panayiota S.; Polychronopoulou, Kyriaki; Belessi, Vassiliki C.; Stathopoulos, Vassilis N.; Pomonis, Phillippos J.; Efstathiou, Angelos M. (2002)A 0.1 wt% Pt supported on La0.7Sr0.2Ce0.1FeO3 solid (mixed oxide containing LaFeO3, SrFeO3-x, CeO2, and Fe2O3 phases) has been studied for the NO/H2/O2 reaction in the 100-400°C range. For a critical comparison, 0.1 wt% ...
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Low-temperature catalytic decomposition of ethylene into H2 and secondary carbon nanotubes over Ni/CNTs
Savva, Petros G.; Polychronopoulou, Kyriaki; Ryzkov, V. A.; Efstathiou, Angelos M. (2010)The present work reports on the production of H2 and secondary carbon nanotubes (CNTs) during catalytic decomposition of ethylene over a novel catalytic system, namely, nickel supported on carbon nanotubes (Ni/CNTs) at ...
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Article
Low-temperature water-gas shift on Pt/Ce0.8La0.2O2-δ-CNT: The effect of Ce0.8La0.2O2-δ/CNT ratio
Petallidou, Klito C.; Polychronopoulou, Kyriaki; Fierro, José Luis García; Efstathiou, Angelos M. (2015)Hybrid materials of (100 - x) wt% Ce0.8La0.2O2-δ-x wt% CNT composition (x = 0, 7.5, 20.5, 32.5, 44.1 and 100) were synthesized using the urea-assisted co-precipitation method and used as supports of 0.5 wt% Pt toward the ...
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Article
NO x control via H 2-selective catalytic reduction (H 2-SCR) technology for stationary and mobile applications
Polychronopoulou, Kyriaki; Efstathiou, Angelos M. (2012)This review paper provides an overview of the use of hydrogen (H 2) gas towards the selective catalytic reduction of nitrogen oxides (NO x) under strongly oxidizing conditions found in many industrial flue gas streams and ...
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Article
Novel Fe-Mn-Zn-Ti-O mixed-metal oxides for the low-temperature removal of H2S from gas streams in the presence of H2, CO 2, and H2O
Polychronopoulou, Kyriaki; Cabello Galisteo, F.; López Granados, M.; Fierro, José Luis García; Bakas, Thomas V.; Efstathiou, Angelos M. (2005)The efficiency of Fe-Mn-Zn-Ti-O mixed-metal oxides of varying composition prepared by sol-gel methods toward removal of H2S from a gas mixture containing 0.06 vol% H2S, 25 vol% H2, 7.5 vol% CO 2, and 1-3 vol% H2O was studied ...
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Article
Novel Zn-Ti-based mixed metal oxides for low-temperature adsorption of H2S from industrial gas streams
Polychronopoulou, Kyriaki; Fierro, José Luis García; Efstathiou, Angelos M. (2005)The efficiency of various Zn-Ti-based mixed metal oxides prepared by the sol-gel method towards H2S adsorption from a gas mixture containing 0.06 vol.% H2S, 25 vol.% H2, 7.5 vol.% CO2 and 1 vol.% H2O was studied in the ...
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Article
Oxy-chlorination as an effective treatment of aged Pd/CeO 2-Al 2O 3 catalysts for Pd redispersion
Lambrou, Panayiota S.; Polychronopoulou, Kyriaki; Petallidou, Klito C.; Efstathiou, Angelos M. (2012)The present work reports on the effects of oxy-chlorine gas treatment (use of Cl 2/O 2/He gas mixture) applied on a 5wt% Pd/20wt% CeO 2-Al 2O 3 catalyst towards Pd redispersion. X-ray diffraction (XRD), X-ray photoelectron ...
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Article
The phenol steam reforming reaction over MgO-based supported Rh catalysts
Polychronopoulou, Kyriaki; Fierro, José Luis García; Efstathiou, Angelos M. (2004)The phenol steam reforming reaction toward H2 formation has been investigated in the 575-730°C range over MgO, CeO2, and ZrO 2 single metal oxides and various mixed metal oxides such as Mg-Ce-O, Mg-Zr-O, and Mg-Ce-Zr-O, ...
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Article
The role of oxygen and hydroxyl support species on the mechanism of H 2 production in the steam reforming of phenol over metal oxide-supported-Rh and -Fe catalysts
Polychronopoulou, Kyriaki; Costa, Costas N.; Efstathiou, Angelos M. (2006)The aim of this work was to probe for the first time the back-spillover of labile O and OH species during steam reforming of phenol towards H2 production over Rh and Fe supported on MgO, Mg-Ce-O and Mg-Ce-Zr-O metal oxides. ...
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Article
Spillover of labile OH, H, and O species in the H2 production by steam reforming of phenol over supported-Rh catalysts
Polychronopoulou, Kyriaki; Efstathiou, Angelos M. (2006)The aim of this work was to probe the back-spillover of labile O, OH and H species during steam reforming of phenol towards H2 production in the 773-1028 K range over Rh supported on MgO and Mg-Ce-Zr-O mixed-metal oxides. ...
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Article
The steam reforming of phenol reaction over supported-Rh catalysts
Polychronopoulou, Kyriaki; Costa, Costas N.; Efstathiou, Angelos M. (2004)The steam reforming of phenol reaction towards H2 production was studied in the 575-730°C range over Rh supported on CeO2, ZrO2 and SiO2 single metal oxides and various mixed metal oxides such as CeO2-SiO2, ZrO2-SiO2 and ...
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Tailoring MgO-based supported Rh catalysts for purification of gas streams from phenol
Polychronopoulou, Kyriaki; Giannakopoulos, K.; Efstathiou, Angelos M. (2012)The present work is focused on the sol-gel synthesis, characterization and catalytic performance evaluation of novel Mg-Ce-Zr-O-based mixed oxides supported Rh catalysts for the purification of H 2-rich gas streams from ...
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Article
Water-gas shift reaction on Pt/Ce1- xTixO 2-δ: The effect of Ce/Ti ratio
Petallidou, Klito C.; Polychronopoulou, Kyriaki; Boghosian, Soghomon; Garcia-Rodriguez, S.; Efstathiou, Angelos M. (2013)Pt nanoparticles (1.2-2.0 nm size) supported on Ce1-xTi xO2-δ (x = 0, 0.2, 0.5, 0.8, and 1.0) carriers synthesized by the citrate sol-gel method were tested toward the water-gas shift (WGS) reaction in the 200-350 C range. ...