NO interaction with thermally activated CaO and SrO surfaces

Yanagisawa, Yasunori

doi:10.1016/0169-4332(96)00299-1

Cited by 19 publications

(24 citation statements)

References 10 publications

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“…However, the probability of its formation in the absence of excess electrons is expected to be much lower. The activity of unreduced surfaces has also been addressed by Yanagisawa and was again explained by the formation of an (NO) 2 intermediate, providing the necessary N−N bond.…”

Section: Discussionmentioning

confidence: 90%

Effects of O₂ on the Reduction of NO over Prereduced CaO Surfaces: A Mechanistic Understanding

Acke

Panas

1999

J. Phys. Chem. B

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The effect of O 2 on the reduction of NO over prereduced CaO surfaces is investigated. The experimental results suggest the existence of at least three different reaction channels, of which two are related to the high-temperature reduction of the CaO surfaces and involve the use of extra electrons in breaking the NO bond. The third reaction channel does not employ extra electrons for bond breaking, but the activity is affected by the amount of adsorbed surface oxygens. The difference between the former two reaction channels is found in the temperature needed for an observable activity. The reaction channel which is already active at low temperatures is described by a model based on F-centers, whereas the one which needs elevated temperatures involves a hole transport through the bulk. The activation energy for this transport is determined experimentally using a temperature-programmed reaction technique as well as theoretically by means of ab initio quantum chemistry calculations. Room-temperature exposure to O 2 is suggested to result in a poisoning of the F-centers, but has only a minor effect on the reaction channel proposed for high temperatures. Effects on the reduction of NO of time as well as temperature for the O 2 exposure step are also investigated and found to be consistent with an understanding based on the coexistence of different reaction channels.

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Section: Discussionmentioning

confidence: 90%

Effects of O₂ on the Reduction of NO over Prereduced CaO Surfaces: A Mechanistic Understanding

Acke

Panas

1999

J. Phys. Chem. B

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“…On alkaline earth metal oxides such as MgO and CaO, negatively charged nitrosyl ions NO − and dimeric hyponitrite ion (N 2 O 2 ) 2− are also observed. In this case, the negative charge is reported to lead to a weakening of the bond stretch with frequencies below 1500 cm −1 [79,82]. Earlier works reported on the reaction of nitric oxide with oxygen on an oxide surface yielding nirate-nirite compounds.…”

Section: Molecular Spectroscopy Characterizationmentioning

confidence: 94%

Bi2O3 as a selective sensing material for NO detection

Cabot

Marsal

Arbiol

et al. 2004

Sensors and Actuators B: Chemical

210

112

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“…The metal-oxide substrates investigated in this study focus on the alkaline earth oxides. The adsorption of NO on these surfaces has been subject of a number of investigations, mainly by infrared spectroscopy. − Yanagisawa tried to correlate IR spectra with temperature-programmed desorption profiles in an attempt to characterize surface-adsorbed intermediate species on CaO and SrO …”

Section: Introductionmentioning

confidence: 99%

“…Numerous absorption bands were observed, which complicated the assignment. The activity of alkaline earth oxides, especially CaO substrates, toward the reduction of NO has been attributed to the presence of impurities which can act as, or induce, sites for accepting excess electrons during surface-oxygen abstraction by a reducing agent. − Low-temperature activity toward the reduction of NO, in the absence of a reducing agent, was observed for heat-treated CaO surfaces …”

Section: Introductionmentioning

confidence: 99%

Role of Adsorbed Surface Oxygen in the Adsorption of NO on Alkaline Earth Oxides and Pt-Promoted CaO Surfaces

Acke

Skoglundh

1999

J. Phys. Chem. B

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Adsorbed surface oxygens are formed on CaO, SrO, and BaO during exposure to N2O, and their presence is shown to affect the room-temperature NO adsorption. Information about the adsorbed intermediates is contained in the desorption products and in the desorption temperatures during the subsequent heating ramp in Ar. The presence of adsorbed oxygen species increases the total amount of adsorbed NO for CaO and BaO substrates, whereas for SrO the adsorbed intermediate is stabilized. Two NO desorption peaks are found for CaO and SrO, one at low and one at high temperature. The former is assigned to adsorbed NO, whereas the latter is assigned to adsorbed −NO2 and/or −NO3 species. NO adsorption as −NO2 and/or −NO3 species finds evidence in the corresponding O2 desorption. Only one NO desorption peak is found for BaO. This NO desorption peak disappears in the absence of preadsorbed surface oxygens. O2 desorption is observed, even in the absence of any preadsorbed surface oxygens, for CaO and SrO substrates. This suggests NO bond dissociation upon NO adsorption. The effect of the promotion of CaO by Pt has also been investigated. The respective desorption profiles are similar to those for the unpromoted CaO with preadsorbed surface oxygens, although the amounts are significantly increased.

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NO interaction with thermally activated CaO and SrO surfaces

Cited by 19 publications

References 10 publications

Effects of O₂ on the Reduction of NO over Prereduced CaO Surfaces: A Mechanistic Understanding

Effects of O₂ on the Reduction of NO over Prereduced CaO Surfaces: A Mechanistic Understanding

Bi2O3 as a selective sensing material for NO detection

Role of Adsorbed Surface Oxygen in the Adsorption of NO on Alkaline Earth Oxides and Pt-Promoted CaO Surfaces

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NO interaction with thermally activated CaO and SrO surfaces

Cited by 19 publications

References 10 publications

Effects of O2 on the Reduction of NO over Prereduced CaO Surfaces: A Mechanistic Understanding

Effects of O2 on the Reduction of NO over Prereduced CaO Surfaces: A Mechanistic Understanding

Bi2O3 as a selective sensing material for NO detection

Role of Adsorbed Surface Oxygen in the Adsorption of NO on Alkaline Earth Oxides and Pt-Promoted CaO Surfaces

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Product

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Effects of O₂ on the Reduction of NO over Prereduced CaO Surfaces: A Mechanistic Understanding

Effects of O₂ on the Reduction of NO over Prereduced CaO Surfaces: A Mechanistic Understanding