Adsorption and Reactivity of No on Copper-on-Alumina Catalysts

Centi, Gabriele; Perathoner, Siglinda; Biglino, Daniele; Giamello, Elio

doi:10.1006/jcat.1995.1062

Cited by 165 publications

(68 citation statements)

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“…7(b)) resulted in the appearance of two distinct bands at 1230 and 1300 cm −1 which can be assigned to bridged nitrite and nitrate species on Al or Mn sites, although the precise assignment of these bands is difficult due to the considerable number of species which absorb in this region [44][45][46]. Upon exposure to the NO/O 2 /Ar gas stream at 300 • C, a strong band at 1552 cm −1 and a weak band at 1300 cm −1 were observed.…”

Section: No X Species Studied By In Situ Driftsmentioning

confidence: 97%

NO storage and reduction properties of model manganese-based lean NO trap catalysts

Zhang

Chen

Wang

et al. 2015

Applied Catalysis B: Environmental

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a b s t r a c tIn order to study the role of manganese in LNT catalysis, model Pd/Mn/Ba/Al, Pd/Mn/Al and Pd/Ba/Al catalysts were prepared and characterized. Both Mn-containing catalysts exhibited higher activity for NO oxidation to NO 2 than the Pd/Ba/Al reference catalyst, although NO x -TPD experiments showed that adsorbed NO x species were weakly bound on Pd/Mn/Al. Consequently, the presence of Ba was essential for high storage capacity. Compared to the Pd/Ba/Al reference, Pd/Mn/Ba/Al showed significantly improved NO x conversion under lean-rich cycling conditions as a consequence of its increased activity for NO oxidation and hence, superior NO x storage efficiency. In addition, the presence of Mn greatly lessened the inhibiting effects of H 2 O and CO 2 on cycle-averaged NO x conversion, this being due to the facile decomposition of manganese carbonate at low temperatures as evidenced by DRIFTS. Significantly, the Pd/Mn/Ba/Al catalyst displayed comparable activity to a traditional LNT catalyst of the Pt/Ba/Al type, showing the promising prospect of such new type of LNT catalysts.

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Section: No X Species Studied By In Situ Driftsmentioning

confidence: 97%

NO storage and reduction properties of model manganese-based lean NO trap catalysts

Zhang

Chen

Wang

et al. 2015

Applied Catalysis B: Environmental

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“…Adsorbed ammonia generates several bands in the investigated region at 175°C. The band at 1458 cm )1 can be assigned to NH 4 + since peaks in this area are reported to be generated by ammonium ions arising from the protonation of ammonia on Brønsted acid sites, and the band around 1620 cm )1 has been assigned to Lewis bound ammonia by the same authors [19,23,[33][34][35][36]. Another possible assignment of the band around 1620 cm )1 is water [36][37][38][39].…”

Section: No X Adsorptionmentioning

confidence: 96%

Identification of adsorbed species on Cu-ZSM-5 under NH3 SCR conditions

et al. 2007

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The selective catalytic reduction of nitrogen oxides with ammonia as the reducing agent was studied using Fourier transform infrared (FTIR) spectroscopy. The adsorbed species found on a Cu-ZSM-5 powder during exposure to NO, NO 2 or NH 3 was compared to the adsorbed species identified during SCR conditions. A blocking effect caused by ammonia at 175°C was investigated by a stepwise increase of the ammonia concentration, and the spectra indicated that the formation of nitrites or nitrates decreased as surface coverage of ammonia increased. No such effect was observed at 350°C, since the oxidation of ammonia results in very low ammonia coverage. The effect of changes in the NO to NO 2 ratio was also studied at 350°C, and the species identified during SCR reaction indicated that the enhanced activity at equimolecular amounts of NO and NO 2 possibly involves gas phase components as well as adsorbed species.

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“…Delahay et al [11] correlated the presence of CuO aggregates to the low temperature N 2 O formation. Centi et al [38] suggested that N 2 O formation originates from the decomposition of ammonium nitrate intermediate, at low temperature. At high temperature, Delahay et al [11] postulated copper ions or copper dimers [CuOCu] 2+ as active species in the formation of N 2 O.…”

Section: N 2 O Formationmentioning

confidence: 99%

Kinetic modeling of NH3-SCR over a supported Cu zeolite catalyst using axial species distribution measurements

Auvray

Partridge

Choi

et al. 2015

Applied Catalysis B: Environmental

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a b s t r a c tIn this study, a kinetic model is developed for NH 3 -SCR over a honeycomb-monolith-supported Cuzeolites using intra-catalyst axial species distribution measurements. An ammonia TPD experiment, together with micro calorimetry data were used for tuning the ammonia adsorption and desorption properties. The spatial distribution for NO oxidation, NH 3 oxidation and NH 3 "Standard" SCR were modeled between 200 and 400 • C. Four-step protocol measurements were employed in order to validate the transient functions of the model. The resulting kinetic model provides good spatiotemporal simulation of the SCR reaction and component reactions throughout the monolith catalyst system.

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Adsorption and Reactivity of No on Copper-on-Alumina Catalysts

Cited by 165 publications

References 0 publications

NO storage and reduction properties of model manganese-based lean NO trap catalysts

NO storage and reduction properties of model manganese-based lean NO trap catalysts

Identification of adsorbed species on Cu-ZSM-5 under NH3 SCR conditions

Kinetic modeling of NH3-SCR over a supported Cu zeolite catalyst using axial species distribution measurements

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