Browsing by Subject "Oxygen"

Article

Adaptive VN/Ag nanocomposite coatings with lubricious behavior from 25 to 1000 °c

Aouadi, S. M.; Singh, D. P.; Stone, D. S.; Polychronopoulou, K.; Nahif, F.; Rebholz, Claus; Muratore, C.; Voevodin, A. A. (2010)

A two-phase nanocomposite coating that consists of inclusions of silver in a vanadium nitride matrix (VN/Ag) was investigated as a potential adaptive coating with a reduced friction coefficient from 25 to 1000 °C. This ...

Article

Alcoholysis/hydrolysis of 1,1′-carbonyldiimidazole as a means of preparing unprecedented, imidazole-containing one-dimensional coordination polymers of copper(II)

Stamatatos, Theocharis C.; Perlepes, Spyros P.; Raptopoulou, Catherine P.; Terzis, Aris; Patrickios, Costas S.; Tasiopoulos, Anastasios J.; Boudalis, Athanassios K. (2009)

The use of 1,1′-carbonyldiimidazole, (im)2CO, for the synthesis of imidazolate (im-) and/or imidazole (Him)-containing copper(II) coordination polymers is described. The [Cu2(O 2CMe)4(H2O)2]/(im)2CO reaction system in EtOH ...

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

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

Deactivation of Pd/Ce 0.5Zr 0.5O 2 model three-way catalyst by P, Ca and Zn deposition

Christou, Stavroula Y.; García-Rodríguez, S.; Fierro, José Luis García; Efstathiou, Angelos M. (2012)

The negative effects of P, P-Ca and P-Zn deposition on the surface of a model 1wt% Pd/Ce 0.5Zr 0.5O 2 " three-way" catalyst (TWC) on its structural, morphological, textural, oxygen storage and release, and catalytic ...

Article

Direct detection of Fe(IV)=O intermediates in the cytochrome aa3 oxidase from Paracoccus denitrificans[H2O2 reaction

Pinakoulaki, Eftychia; Pfitzner, U.; Ludwig, B.; Varotsis, Constantinos (2003)

We report the first evidence for the formation of the "607- and 580-nm forms" in the cytochrome oxidase aa3/H2O2 reaction without the involvement of tyrosine 280. The pKa of the 607-580-nm transition is 7.5. The 607-nm ...

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

Effect of thermal aging on the transient kinetics of oxygen storage and release of commercial Cex Zr1-x O2-based solids

Christou, Stavroula Y.; Bradshaw, H.; Butler, C.; Darab, J.; Efstathiou, Angelos M. (2009)

The use of powerful analytical methodologies for the evaluation of the performance of commercial oxygen storage materials based on oxygen transient isothermal isotopic exchange experiments is illustrated in this study. Ce ...

Article

The effects of Fe on the oxygen storage and release properties of model Pd-Rh/CeO2-Al2O3 three-way catalyst

Lambrou, Panayiota S.; Efstathiou, Angelos M. (2006)

This work attempts to gain fundamental information about the role of Fe in the chemical deactivation of a three-way catalyst (TWC), with Fe originating from materials used in the construction of automotive engines and ...

Article

The effects of P-poisoning of CexZr1-xO2 on the transient oxygen storage and release kinetics

Christou, Stavroula Y.; Efstathiou, Angelos M. (2013)

The present work reports on the investigation of the effects of chemical poisoning of CexZr1-xO2 solids by phosphorous (P) on the kinetics of oxygen storage and release (OSR) of the thus derived P-contaminated solids, as ...

Article

The effects of the use of weak organic acids on the improvement of oxygen storage and release properties of aged commercial three-way catalysts

Lambrou, Panayiota S.; Christou, Stavroula Y.; Fotopoulos, Apostolos P.; Foti, F. K.; Angelidis, Thomas N.; Efstathiou, Angelos M. (2005)

The efficiency of weak organic acid solutions for improving the oxygen storage and release properties of aged commercial three-way catalysts (TWC) has been investigated. For the first time, three candidate leaching solutions, ...

Article

Employment of methyl 2-pyridyl ketone oxime in manganese non-carboxylate chemistry: MnII2MnIV and MnII 2MnIII6 complexes

Stoumpos, Constantinos C.; Stamatatos, Theocharis C.; Sartzi, H.; Roubeau, O.; Tasiopoulos, Anastasios J.; Nastopoulos, Vassilios; Teat, S. J.; Christou, George; Perlepes, Spyros P. (2009)

The employment of the anion of methyl 2-pyridyl ketone oxime (mpko -) as a tridentate chelating/bridging ligand in manganese chemistry is described. The inorganic anion (Br-, ClO4-) used in the reaction affects the identity ...

Article

Influence of oxychlorination treatments on the redox and oxygen storage and release properties of thermally aged Pd-Rh/CexZr1-xO 2/Al2O3 model three-way catalysts

Daley, R. A.; Christou, Stavroula Y.; Efstathiou, Angelos M.; Anderson, J. A. (2005)

Model Pd-Rh/Al2O3 three-way catalysts with and without CexZr1-xO2 as oxygen storage component have been compared in their fresh, thermally aged and oxychlorinated treated surface states to determine the potential regenerating ...

Article

Interesting copper(ii)-assisted transformations of 2-acetylpyridine and 2-benzoylpyridine

Kitos, Alexandros A.; Efthymiou, Constantinos G.; Manos, Manolis J.; Tasiopoulos, Anastasios J.; Nastopoulos, Vassilios; Escuer, Albert; Perlepes, Spyros P. (2016)

The reactions of various copper(ii) sources with 2-acetylpyridine, (py)(me)CO, and 2-benzoylpyridine, (py)(ph)CO, under strongly basic conditions have been studied and novel ligand transformations have been discovered. ...

Article

Kinetic and mechanistic studies of the water-gas shift reaction on Pt/TiO2 catalyst

Kalamaras, Christos M.; Panagiotopoulou, P.; Kondarides, D. I.; Efstathiou, Angelos M. (2009)

A detailed kinetic and mechanistic study of the water-gas shift (WGS) reaction on a 0.5 wt% Pt/TiO2 catalyst has been carried out. The dependence of kinetic reaction rate on the partial pressures of reactants (CO, H2O) and ...

Article

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 ...

Article

Low-temperature purification of gas streams from phenol by steam reforming over novel supported-Rh catalysts

Constantinou, D. A.; Efstathiou, Angelos M. (2010)

The purification of gas streams from phenol at low-temperatures (350-550 °C) was investigated by its reaction with steam over novel catalytic systems, namely 0.5 wt% Rh supported on Ce0.15Zr0.85O2, Ce0.15Zr0.83Mg0.02O2 and ...

Article

Low-temperature water-gas shift on Pt/Ce1-xLaxO2-δ: Effect of Ce/La ratio

Petallidou, Klito C.; Efstathiou, Angelos M. (2013)

Pt nanoparticles (1.0-1.4nm size) supported on Ce1-xLaxO2-δ (x=0.0, 0.2, 05, 0.8 and 1.0) carriers, the latter prepared by the citrate sol-gel method, were tested toward the water-gas shift (WGS) reaction in the 200-400°C ...

Conference Object

Mechanical stress regulates tissue oxygenation, cancer cell proliferation and drug delivery during progression of solid tumors

Mpekris, F.; Angeli, S.; Pirentis, A. P.; Stylianopoulos, T. (Springer Verlag, 2016)

Oxygen supply plays a central role in cancer cell proliferation. While vascular density increases at the early stages of carcinogenesis, mechanical solid stresses developed during growth compress tumor blood vessels and, ...

Article

A [Mn32] double-decker wheel

Manoli, Maria; Inglis, R.; Manos, Manolis J.; Nastopoulos, Vassilios; Wernsdorfer, W.; Brechin, E. K.; Tasiopoulos, Anastasios J. (2011)

Inventing the double wheel: A mixed-valent [Mn32] cluster with a very rare "double-decker" wheel topology (see its metal-oxygen core: MnIII blue, MnII pink, O red) is reported. It is by far the highest-nuclearity example ...