Browsing by Subject "X ray photoelectron spectroscopy"

Article

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 ...

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

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

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 calcination temperature on the oxygen storage and release properties of CeO2 and Ce-Zr-O metal oxides modified by phosphorus incorporation

Larese, C.; López Granados, M.; Mariscal, R.; Fierro, José Luis García; Lambrou, Panayiota S.; Efstathiou, Angelos M. (2005)

The present work reports on the effects of calcination temperature (T c) on the oxygen storage and release properties of CeO2 and Ce0.8Zr0.2O2 solids deliberately contaminated with CePO4. Pulsed-feed and stepped-feed dynamic ...

Conference Object

Effect of Cu content on the tribological performance of Cr-N coatings at high temperatures (840°C)

Polychronopoulou, K.; Rebholz, Claus; Demas, N. G.; Polycarpou, A. A.; Gibson, P. N. (Affiliation: Department of Mechanical and Manufacturing Eng., University of Cyprus, Nicosia, CyprusAffiliation: Department of Mechanical Science and Eng., University of Illinois at Urbana-Champaign, Urbana, IL, United StatesAffiliation: Institute for Health and Consumer Protection, Joint Res. Centre of the European Commission, Ispra (VA), ItalyCorrespondence Address: Polychronopoulou, K.Department of Mechanical and Manufacturing Eng., University of Cyprus, Nicosia, Cyprus, 2010)

Cr-N and Cu-Cr-N coatings with Cu content between 3-65 at.%, Cu/Cr ratios in the 0.04-4.5 range and 21-27 at.% N, synthesized by twin e-beam Physical Vapor Deposition (EBPVD) at 450°C, were investigated. Using X-ray ...

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

Effects of calcination temperature on the stability of CePO4 detected in vehicle-aged commercial three-way catalysts

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

Samples extracted from a vehicle-aged commercial TWC monolith (the inlet part of the first cartridge) have been shown to contain CePO4. The effects of calcination temperature in the 773-1173K range on these samples have ...

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

Enhancing the nanoscratch resistance of pulsed laser deposited DLC films through molybdenum-doping

Constantinou, M.; Pervolaraki, M.; Koutsokeras, L.; Prouskas, C.; Patsalas, P.; Kelires, P.; Giapintzakis, John; Constantinides, G. (2017)

Pulsed laser deposition was used to grow DLC and molybdenum-doped DLC (DLC:Mo) films, with metal contents up to 3.2 at.%, on silicon substrates. The microstructural details of the films were investigated using X-ray ...

Article

Evaluating the microstructure and performance of nanocomposite PVD TiAlBN coatings

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

Physical vapour deposition (PVD) TiAlBN coatings can exhibit excellent wear resistance, with optimised coating compositions demonstrating a 150% increase in lifetime compared to standard TiAlN coatings in wet-cutting drill ...

Article

Few-layer graphene-like flakes derived by plasma treatment: A potential material for hydrogen adsorption and storage

Kostoglou, N.; Tarat, A.; Walters, I.; Ryzhkov, V.; Tampaxis, C.; Charalambopoulou, Georgia; Steriotis, T.; Mitterer, C.; Rebholz, Claus (2016)

A novel, one-step, wet-free, environmental friendly and high-yield method for producing few-layer graphene powders with large surface areas (up to 800 m2/g) and narrow nanopore sizes (0.7-0.8 nm) using plasma-induced ...

Article

From beads-on-a-string to colloidal aggregation: novel crystallization phenomena in the PEO-SDS system

Leontidis, Epameinondas; Kyprianidou-Leodidou, Tasoula; Caseri, Walter; Kyriacou, Kyriacos C. (1999)

The anionic surfactant sodium dodecyl sulfate (SDS) interacts strongly with poly(ethylene oxide) (PEO) in aqueous solution, forming micellar aggregates attached to the polymer chains above the so-called critical association ...

Article

From colloidal aggregates to layered nanosized structures in polymer-surfactant systems. 1. Basic phenomena

Leontidis, Epameinondas; Kyprianidou-Leodidou, Tasoula; Caseri, Walter; Robyr, P.; Krumeich, F.; Kyriacou, Kyriacos C. (2001)

In this work, we examine the rich crystallization behavior that occurs in PbII/S-II/poly(ethylene oxide) (PEO)/sodium dodecyl sulfate (SDS) systems, in which the anionic surfactant interacts strongly with the polymer ...

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

Microstructure and nanomechanical properties of pulsed excimer laser deposited DLC:Ag films: Enhanced nanotribological response

Constantinou, M.; Pervolaraki, M.; Nikolaou, P.; Prouskas, C.; Patsalas, P.; Kelires, P.; Giapintzakis, John; Constantinides, G. (2017)

Diamond-like carbon:silver (DLC:Ag) thin films, with metal contents as high as 16.8 at.%, have been deposited on silicon substrates using pulsed excimer laser deposition

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 ...