Browsing by Author "Costa, Costas N."

Article

Catalytic activity of high surface area mesoporous mn-based mixed oxides for the deep oxidation of methane and lean-nox reduction

Stathopoulos, Vassilis N.; Belessi, Vassiliki C.; Costa, Costas N.; Neophytides, Stylianos G.; Falaras, Polycarpos; Efstathiou, Angelos M.; Pomonis, Phillippos J. (2000)

Article

Catalytic behavior of La-Sr-Ce-Fe-O mixed oxidic/perovskitic systems for the NO+CO and NO+CH4+O2 (lean-NOx) reactions

Belessi, Vassiliki C.; Costa, Costas N.; Bakas, Thomas V.; Anastasiadou, T.; Pomonis, Phillippos J.; Efstathiou, Angelos M. (2000)

Mixed oxides of the general formula La0.5SrxCeyFeOz were prepared by using the nitrate method and characterized by XRD and Mossbauer techniques. The crystal phases detected were perovskites LaFeO3 and SrFeO3-x and oxides ...

Article

Catalytic removal of nitrates from waters

Constantinou, C. L.; Costa, Costas N.; Efstathiou, Angelos M. (2010)

The selective catalytic reduction of nitrates (NO3 -) in pure water towards N2 formation by the use of gaseous H2 and in the presence of O2 (air) at 1 atm total pressure and 25 °C has been investigated over Pd-Cu supported ...

Article

The CH4/NO/O2 "lean-deNOx" reaction on mesoporous Mn-based mixed oxides

Stathopoulos, Vassilis N.; Costa, Costas N.; Pomonis, Phillippos J.; Efstathiou, Angelos M. (2001)

High surface area Mn-based porous oxides (MANPO) containing additives like Ce, Sr and La were found to be very active and selective materials under 0.67% CH4/0.2% NO/5% O2 "lean-deNOx" conditions in the 200-300°C low-temperature ...

Article

Comparative study of La-Sr-Fe-O perovskite-type oxides prepared by ceramic and surfactant methods over the CH4 and H2 lean-deNOx

Stathopoulos, Vassilis N.; Belessi, Vassiliki C.; Bakas, Thomas V.; Neophytides, Stylianos G.; Costa, Costas N.; Pomonis, Phillippos J.; Efstathiou, Angelos M. (2009)

Mixed oxides of the general formula La0.8Sr0.2FeO3-x were prepared by ceramic and surfactant methods and tested towards the NO/H2/O2 and NO/CH4/O2 lean-deNOx reactions in the 200-450 °C range. The materials were characterized ...

Article

Dynamics of oxygen storage and release on commercial aged Pd-Rh three-way catalysts and their characterization by transient experiments

Lambrou, Panayiota S.; Costa, Costas N.; Christou, Stavroula Y.; Efstathiou, Angelos M. (2004)

The present work has provided new fundamental information on the effects of aging (mileage, km) of a commercial Pd-Rh (9:1, w/w) three-way catalyst (TWC) on (a) the H 2 chemisorption, (b) the redox properties of washcoat ...

Article

Hydrogen production by ethylene decomposition over Ni supported on novel carbon nanotubes and nanofibers

Savva, Petros G.; Olympiou, G. G.; Costa, Costas N.; Ryzhkov, V. A.; Efstathiou, Angelos M. (2005)

Ethylene decomposition over Ni supported on novel carbon nanotubes (CNT) and nanofibers under consecutive reaction/regeneration cycles to form CO-free hydrogen and carbon deposits have been investigated. The present work ...

Article

Industrial H2-SCR of NO on a novel Pt/MgO-CeO2 catalyst

Costa, Costas N.; Savva, Petros G.; Fierro, José Luis García; Efstathiou, Angelos M. (2007)

We describe here the performance of a novel MgO-CeO2-supported Pt (0.1 wt%) catalyst towards the selective conversion of NO into N2 (SN2 > 80%) by using H2 (H2-SCR) under process conditions similar to those encountered in ...

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% ...

Article

An investigation of the NO/H2/O2 (Lean-deNOx) reaction on a highly active and selective Pt/La0.5Ce0.5MnO3 catalyst

Costa, Costas N.; Efstathiou, Angelos M.; Stathopoulos, Vassilis N.; Belessi, Vassiliki C. (2001)

The NO/H2/O2 reaction has been studied under lean-burn conditions in the 100-400°C range over 0.1 wt% Pt supported on La0.5Ce0.5MnO3 (mixed oxide containing LaMnO3, CeO2, and MnO2 phases). For a critical comparison, 0.1 ...

Article

Low-temperature H2-SCR of NO on a novel Pt/MgO-CeO2 catalyst

Costa, Costas N.; Efstathiou, Angelos M. (2007)

The selective catalytic reduction of NO by H2 under strongly oxidizing conditions (H2-SCR) in the low-temperature range of 100-200 °C has been studied over Pt supported on a series of metal oxides (e.g., La2O3, MgO, Y2O3, ...

Article

Mathematical modeling of the oxygen storage capacity phenomenon studied by CO pulse transient experiments over Pd/CeO2 catalyst

Costa, Costas N.; Christou, Stavroula Y.; Georgiou, Georgios C.; Efstathiou, Angelos M. (2003)

A mathematical model has been developed for the first time to study the oxygen storage capacity (OSC) phenomenon by the CO pulse injection technique over a 1 wt% Pd/CeO2 model catalyst in the 500-700°C range. A two-step ...

Article

Mathematical modeling of the oxygen storage capacity phenomenon studied by CO pulse transient experiments over Pd/CeO2 catalystAAA

Costa, Costas N.; Christou, Stavroula Y.; Georgiou, Georgios C.; Efstathiou, Angelos M. (2003)

A mathematical model has been developed for the first time to study the oxygen storage capacity (OSC) phenomenon by the CO pulse injection technique over a 1 wt% Pd/CeO2 model catalyst in the 500-700°C range. A two-step ...

Article

The mechanism of reduction of NO with H2 in strongly oxidizing conditions (H2-SCR) on a novel Pt/MgO-CeO2 catalyst: Effects of reaction temperature

Savva, Petros G.; Costa, Costas N.; Efstathiou, Angelos M. (2008)

Steady State Isotopic Transient Kinetic Analysis (SSITKA) experiments using on-line Mass Spectrometry (MS) and in situ Diffuse Reflectance Infrared Fourier-Transform Spectroscopy (DRIFTS) have been performed to study ...

Article

Mechanistic aspects of the H2-SCR of NO on a Novel Pt/MgO-CeO2 catalyst

Costa, Costas N.; Efstathiou, Angelos M. (2007)

Steady State Isotopic Transient Kinetic Analysis (SSITKA) coupled with Temperature-Programmed Surface Reaction (TPSR) experiments, using on line Mass Spectroscopy (MS) and in situ DRIFTS have been performed to study essential ...

Article

Near-monodisperse α-hydroxy and α,ω-dihydroxy amine-based polymers: Synthesis and characterization

Costa, Costas N.; Patrickios, Costas S. (1999)

α-Hydroxy and α,ω-dihydroxy polymers of 2-(dimethylamino)ethyl methacrylate (DMAEMA) of various molecular weights were synthesized by group transfer polymerization (GTP) in tetrahydrofuran (THF), using 1-methoxy-1-(trime ...

Article

Pt/Mg-Ce-O catalyst for NO/H2/O2 lean de-Nox reaction

Costa, Costas N.; Efstathiou, Angelos M. (2004)

The NO/H2/O2 reaction was studied under oxidizing conditions in the 100-400 °C range over 0.1 wt% Pt supported on various metal oxides such as MgO, CeO2, SiO2, La2O3, CaO, Y2O3 and TiO2. The Pt/MgO and Pt/CeO2 catalysts ...

Article

The remarkable effect of oxygen on the N2 selectivity of water catalytic denitrification by hydrogen

Constantinou, C. L.; Costa, Costas N.; Efstathiou, Angelos M. (2007)

The selective catalytic reduction of nitrates (NO3-) in pure water toward N2 formation by the use of gaseous H2 and in the presence of O2 (air) at 1 atm total pressure and 25°C has been investigated over Pd-Cu supported ...

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. ...

Article

Selective catalytic reduction of nitric oxide by methane in the presence of oxygen over CaO catalyst

Fliatoura, K. D.; Verykios, Xenophon E.; Costa, Costas N.; Efstathiou, Angelos M. (1999)

The selective catalytic reduction of nitric oxide by methane in the presence of oxygen was studied over CaO catalyst in the temperature range 550-850°C. The nitric oxide conversion-versus-temperature profile was found to ...