Browsing by Author "Costa, Costas N."
Now showing items 21-27 of 27
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The selective catalytic reduction of nitric oxide with methane over La2O3-CaO systems: Synergistic effects and surface reactivity studies of NO, CH4, O2, and CO2 by transient techniques
Costa, Costas N.; Anastasiadou, T.; Efstathiou, Angelos M. (2000)Dispersing La2O3 crystallites in a 5 wt% La2O3-CaO mixed oxide system significantly enhances the intrinsic rate of NO reduction by CH4 in the presence of 5% O2 at 550°C compared to pure La2O3 and CaO phases. A synergistic ...
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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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Article
Synergistic effects of crystal phases and mixed valences in La-Sr-Ce-Fe-O mixed oxidic/perovskitic solids on their catalytic activity for the NO+CO reaction
Belessi, Vassiliki C.; Bakas, Thomas V.; Costa, Costas N.; Efstathiou, Angelos M.; Pomonis, Phillippos J. (2000)Mixed oxidic and perovskite-type materials based on the La, Sr, Ce and Fe elements were prepared using a mixture of nitrates salts and heating at 1000°C. Three groups of solids were synthesized: (i) La(1-y)Ce(y)FeO3 (y=0.2, ...
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Article
Thermal stability of solid and aqueous solutions of humic acid
Kolokassidou, C.; Pashalidis, Ioannis; Costa, Costas N.; Efstathiou, Angelos M.; Buckau, G. (2007)The effects of temperature on the stability of a soil humic acid were studied in the present work. Solid samples of Gohy-573 humic acid (HA) and dissolved ones in aqueous solution (pH 6.0, 0.1 mol L-1 NaClO4) were investigated ...
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Transient isotopic kinetic study of the NO/H2/O2 (lean de-NOx) reaction on Pt/SiO2 and Pt/La-Ce-Mn-O catalysts
Costa, Costas N.; Efstathiou, Angelos M. (2004)Steady-state isotopic transient kinetic analysis (SSITKA) coupled with temperature-programmed surface reaction (TPSR) methods and using in situ mass spectroscopy and DRIFTS have been applied for the first time to study ...
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A two-step reaction mechanism of oxygen release from Pd/CeO2: Mathematical modelling based on step gas concentration experiments
Christou, Stavroula Y.; Costa, Costas N.; Efstathiou, Angelos M. (2004)A mathematical model was developed to study the transient release of oxygen from a 1 wt % Pd/CeO2 catalyst in the 450°-550°C range based on alternate step concentration switches between CO and O2. The proposed mathematical ...
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Understanding the synergistic catalytic effect between la2O 3 and CaO for the CH4 Lean De-NOx reaction: Kinetic and mechanistic studies
Anastasiadou, T.; Loukatzikou, Loukia A.; Costa, Costas N.; Efstathiou, Angelos M. (2005)Doping of La2O3 crystallites with Ca2+ ions significantly enhances the intrinsic rate of NO reduction by CH4 in the presence of 5% O2 at 550°C compared to pure La 2O3 and CaO solids, while the opposite is true after doping ...