Browsing by Subject "XPS"

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

A comparative study of the steam reforming of phenol towards H2 production over natural calcite, dolomite and olivine materials

Constantinou, D. A.; Fierro, José Luis García; Efstathiou, Angelos M. (2010)

Pre-calcined (air, 850 °C) naturally occurring calcite, dolomite and olivine materials were studied for phenol steam reforming towards H2 production. The effect of reaction temperature, feed volume flow rate, and hydrogen ...

Article

The effect of Fe on the catalytic behavior of model Pd-Rh/CeO2-Al2O3 three-way catalyst

Lambrou, Panayiota S.; Savva, Petros G.; Fierro, José Luis García; Efstathiou, Angelos M. (2007)

The present work attempts to address the issue whether iron (Fe) which is accumulated on the surface of "three-way" catalysts (TWCs) used in gasoline-driven cars is a true chemical poison of their catalytic activity. This ...

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

Effects of the CePO 4 on the oxygen storage and release properties of CeO 2 and Ce 0.8Zr 0.2O 2 solid solution

Larese, C.; Galisteo, F. C.; Granados, M. L.; Mariscal, R.; Fierro, José Luis García; Lambrou, Panayiota S.; Efstathiou, Angelos M. (2004)

In an attempt to gain fundamental information about the role of P on the chemical deactivation of a three-way catalyst (TWC), P was deliberatively incorporated in CeO 2 and Ce 0.8Zr 0.2O 2 solid solution. XRD, Raman, XPS, ...

Article

Electron spectroscopic studies of nanocomposite PVD TiAlBN coatings

Baker, M. A.; Rebholz, Claus; Leyland, A.; Matthews, A. (2002)

A range of TiAlBN coatings have been deposited by electron beam evaporation and the optimised composition exhibits a 150% improvement over single phase TiAlN coatings in drilling tests. The coatings have been analysed by ...

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 conversion of phenol into CO, CO 2 and H 2 by steam reforming over La-containing supported Rh catalysts

Constantinou, D. A.; álvarez-Galván, M. C.; Fierro, José Luis García; Efstathiou, Angelos M. (2012)

The steam reforming of phenol in the low-temperature range of 350-550°C was studied over 0.5wt% Rh supported on Ce 0.15Zr 0.85O 2, Zr 0.93La 0.07O 2, and Ce 0.13Zr 0.83La 0.04O 2 mixed metal oxides. The reforming specific ...

Article

Nanostructural studies of PVD TiAlB coatings

Monclus, M. A.; Baker, M. A.; Rebholz, Claus; Stolojan, V.; Gibson, P. N.; Leyland, A.; Matthews, A. (2006)

TiAlB coatings with different compositions were deposited by co-sputtering from TiAl and TiB2 targets onto AISI316 stainless steel substrates at a temperature of 170 °C. The stoichiometry and nanostructure have been studied ...

Article

The nanostructure, wear and corrosion performance of arc-evaporated CrBxNy nanocomposite coatings

Polychronopoulou, K.; Baker, M. A.; Rebholz, Claus; Neidhardt, J.; O'Sullivan, M.; Reiter, A. E.; Kanakis, K.; Leyland, A.; Matthews, A.; Mitterer, C. (2009)

The composition, nanostructure, tribological and corrosion behaviour of reactive arc evaporated CrBxNy coatings have been studied and compared to CrN. The CrBxNy coatings were deposited on a commercial Oerlikon Balzers RCS ...

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 ...

Article

Nucleation of isolated PO4 units on CeO2 driven by high temperatures and the effect on its oxygen storage and release properties

López Granados, M.; Cabello Galisteo, F.; Lambrou, Panayiota S.; Alifanti, M.; Mariscal, R.; Gurbani, A.; Sanz, J.; Sobrados, I.; Efstathiou, Angelos M.; Fierro, José Luis García (2007)

The chemical nature of P-containing species of varying concentration present in CeO2 after impregnation with (NH4)2HPO4 and calcination at 1273 K, and their effects on the oxygen storage and release (OSR) properties of ...

Article

Role of P-containing species in phosphated CeO2 in the deterioration of its oxygen storage and release properties

López Granados, M.; Galisteo, F. C.; Lambrou, Panayiota S.; Mariscal, R.; Sanz, J.; Sobrados, I.; Fierro, José Luis García; Efstathiou, Angelos M. (2006)

The chemical nature of P-containing species incorporated on the surface and within the subsurface regions of CeO2 solid and their effects on the deterioration of the oxygen storage and release properties of phosphated ceria ...

Article

Tribological properties of twin electron-beam evaporated Cr-N and Al-Cr-N coatings under laboratory sliding and drill experiments

Polychronopoulou, K.; Demas, N. G.; Rebholz, Claus; Polycarpou, A. A. (2008)

The tribological behavior of substoichiometric Cr-N and Al-Cr-N coatings prepared by twin electron-beam evaporation at 450°C was studied. Al-Cr-N coatings with Al to Cr ratios in the range of 1-8 (and nitrogen concentrations ...