Browsing by Author "Verykios, Xenophon E."

Article

CO oxidation over Rh dispersed on SiO2, Al2O3 and TiO2: Kinetic study and oscillatory behavior

Ioannides, T.; Efstathiou, Angelos M.; Zhang, Z. L.; Verykios, Xenophon E. (1995)

The kinetic behavior of Rh supported on SiO2, Al2O3, and TiO2 in the CO oxidation reaction has been investigated. It was found that the maximum turnover frequency (TOF) is approximately the same over the three catalysts, ...

Article

Effects of W6+ doping of TiO2 on the reactivity of supported Rh toward NO: Transient FTIR and mass spectroscopy studies

Chafik, T.; Efstathiou, Angelos M.; Verykios, Xenophon E. (1997)

The transient adsorption and dissociation of NO over Rh supported on undoped and W6+-doped TiO2 in the temperature range of 25-450°C has been studied by FTIR and mass spectroscopy. It was found that at 25 °C three kinds ...

Article

Kinetics of methane oxidative coupling on li-doped TiO2 catalysts

Efstathiou, Angelos M.; Boudouvas, D.; Vamvuka, Despina; Verykios, Xenophon E. (1993)

A kinetic study of methane conversion to C2-hydrocarbons was conducted by cofeeding methane and oxygen at 1 bar total pressure over a series of Li-doped TiO2 catalysts. The lithium dopant concentration was varied between ...

Article

Kinetics of methane oxidative coupling on zinc-doped titanium oxide

Efstathiou, Angelos M.; Boudouvas, D.; Vamvuka, Despina; Verykios, Xenophon E. (1992)

A kinetic study of methane conversion to C2-hydrocarbons was conducted by cofeeding methane and oxygen at 1 bar total pressure over a series of zinc-doped TiO2 catalysts. The zinc dopant concentration was varied between 1 ...

Article

A novel analysis of equilibrium adsorption and desorption using transient tracing methods

Szedlacsek, P.; Efstathiou, Angelos M.; Verykios, Xenophon E. (1997)

A novel analysis of adsorption and desorption using transient tracing methods under equilibrium conditions is developed. The analysis performed provides (a) the exchange rate between the gas and surface phases at steady-state, ...

Article

Partial oxidation of methane to synthesis gas over Ru/TiO2 catalysts

Boucouvalas, Yiannis; Zhang, Z. L.; Efstathiou, Angelos M.; Verykios, Xenophon E. (1996)

The catalytic partial oxidation of methane to synthesis gas is investigated over Group VIII metal catalysts. It is shown that while all catalysts promote methane combustion followed by reforming with H2O and CO2, the Ru/TiO2 ...

Article

Partial oxidation of methane to synthesis gas over supported ruthenium catalysts

Boucouvalas, Yiannis; Efstathiou, Angelos M.; Zhang, Z. L.; Verykios, Xenophon E. (1997)

The partial oxidation of methane to synthesis gas has been investigated over Ru supported on SiO2, γ-Al2O3, YSZ (Yttria-stabilized zirconia) and TiO2 catalysts in the temperature range of 550-750°C. The results show that ...

Article

Reforming of methane with carbon dioxide to synthesis gas over supported Rh catalysts

Tsipouriari, Vaso A.; Efstathiou, Angelos M.; Zhang, Z. L.; Verykios, Xenophon E. (1994)

Reforming of methane with carbon dioxide to synthesis gas (CO/H2) has been investigated over rhodium supported on SiO2, TiO2, γ-Al2O3, MgO, CeO2, and YSZ (ZrO2 (8 mol% Y2O3)) catalysts in the temperature range of 650-750°C ...

Article

Reforming of methane with carbon dioxide to synthesis gas over supported rhodium catalysts: I. Effects of support and metal crystallite size on reaction activity and deactivation characteristics

Zhang, Z. L.; Tsipouriari, Vaso A.; Efstathiou, Angelos M.; Verykios, Xenophon E. (1996)

The effects of carrier and metal particle size on the catalytic performance (initial intrinsic activity and deactivation characteristics) of Rh in the reaction of reforming of methane with carbon dioxide were investigated. ...

Article

Reforming of methane with carbon dioxide to synthesis gas over supported rhodium catalysts: II. A steady-state tracing analysis: Mechanistic aspects of the carbon and oxygen reaction pathways to form CO

Efstathiou, Angelos M.; Kladi, Angelica; Tsipouriari, Vaso A.; Verykios, Xenophon E. (1996)

Steady-state tracing techniques have been applied to investigate mechanistic aspects of the CH4 reforming reaction over CO2 over Rh supported on yttria-stabilized zirconia (YSZ) and Al2O3 as catalysts. It was found that ...

Article

The role of lattice oxygen during the oxidative coupling of methane over Li+-Doped TiO2 catalysts

Efstathiou, Angelos M.; Papageorgiou, D.; Verykios, Xenophon E. (1993)

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 ...

Article

The Selective Oxidation of Methane to C2-hydrocarbons over Li+-Doped TiO2: Catalytic and Mechanistic Studies

Efstathiou, Angelos M.; Papageorgiou, D.; Verykios, Xenophon E. (1994)

This chapter presents the performance of Li+-doped TiO2 catalysts and mechanistic conclusions derived from various transient experiments related to the reactivity of C2–hydrocarbons with the lattice oxygen of the catalyst. ...

Article

The selective oxidation of methane to C2-hydrocarbons over lithium-doped TiO2 catalysts

Papageorgiou, D.; Efstathiou, Angelos M.; Verykios, Xenophon E. (1994)

The oxidative coupling of methane (OCM) to C2-hydrocarbons was studied on a series of lithiumdoped titania catalysts by cofeeding methane (PCH4 = 0.5 bar) and oxygen (Po2 = 0.07-0.16 bar) at 1 bar total pressure in the ...

Article

A steady-state tracing kinetic analysis of oxidative coupling of methane over Li+-doped TiO2: Mechanistic aspects of the carbon and oxygen reaction pathways to form CO2

Efstathiou, Angelos M.; Lacombe, S.; Mirodatos, C.; Verykios, Xenophon E. (1994)

A steady-state tracing kinetic study of the oxidative coupling of methane reaction at 800°C over Li+-doped TiO2 catalyst was performed. In particular, the carbon and oxygen reaction pathways which lead to the formation of ...

Article

Transient kinetic study of the oxidation and hydrogenation of carbon species formed during CH4/He, CO2/He, and CH4/CO2 reactions over Rh/Al2O3 catalyst

Tsipouriari, Vaso A.; Efstathiou, Angelos M.; Verykios, Xenophon E. (1996)

The dissociation of CH4 and CO2 on 0.5 wt% Rh/Al2O3 catalyst has been investigated at 650°C using transient techniques with on-line mass spectrometry. The dissociation of CH4 results in the formation of large amounts of ...

Article

Transient kinetic study of the reaction of C2H4 and C2H6 with the lattice and adsorbed oxygen species of Li+-doped TiO2 catalysts

Papageorgiou, D.; Efstathiou, Angelos M.; Verykios, Xenophon E. (1994)

A transient kinetic study of the reactions of C2H4 and C2H6 with lattice oxygen, O2- (in the absence of gaseous oxygen), and "adsorbed" oxygen (in the presence of gaseous oxygen) species over undoped and Li+-doped TiO2 OCM ...

Article

Transient kinetic study of the reaction of CH4 and C2H6 with the lattice oxygen of Li+-doped TiO2 catalyst

Efstathiou, Angelos M.; Papageorgiou, D.; Verykios, Xenophon E. (1993)

A transient kinetic study of the reaction of CH4/He and C2H6/He with the lattice oxygen of Li+-doped TiO2 catalyst was performed. The results obtained indicate that lattice oxygen species must be considered as oxidation ...

Article

Transient methods in heterogeneous catalysis: Experimental features and application to study mechanistic aspects of the CH4/O2 (OCM), NH3/O2 and NO/He reactions

Efstathiou, Angelos M.; Verykios, Xenophon E. (1997)

Experimental features of the transient method using concentration forcing functions to study the surface dynamics of a heterogeneous catalytic reaction at 1 atm and with on line mass spectroscopy are discussed. Emphasis ...