Impact of copper on the performance and sulfur tolerance of barium-based NOx storage-reduction catalysts

Hammache, Sonia; Evans, Lindsey; Coker, Eric N.; Miller, James E.

doi:10.1016/j.apcatb.2007.09.010

Cited by 16 publications

(8 citation statements)

References 25 publications

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“…The NH3 concentration increases after the 2 nd rich pulse, and reaches a maximum at 300°C. Conversely, N2O formation decreases with the raise of the temperature and shows a maximum at low temperature (250°C), in agreement with the literature [6,7]. Note that the N2O concentration is much lower than ammonia.…”

Section: Resultssupporting

confidence: 92%

Cooperative effect of Pt–Rh/Ba/Al and CuZSM-5 catalysts for NO reduction during periodic lean-rich atmosphere

Corbos¹,

Haneda²,

Courtois³

et al. 2008

Catalysis Communications

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NOx removal efficiency was investigated with a combination of model Pt-Rh/Ba/Al and Cu-ZSM-5 catalysts using periodic fluctuations between lean (100 s) and rich (10 s) atmosphere. NOx removal is greatly improved at 250°C and 300°C by physically mixing the two catalysts. The mixed catalyst shows a NOx removal activity almost double as compared to a system where Pt-Rh/Ba/Al catalyst is situated upstream and CuZSM-5 downstream the gas flow. FT-IR characterization shows that CuZSM-5 catalyst enhances the formation of NCO species on alumina during rich conditions. These NCO are further hydrolyzed to NH3 under lean condition which acts as a reductant for NOx.

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Section: Resultssupporting

confidence: 92%

Cooperative effect of Pt–Rh/Ba/Al and CuZSM-5 catalysts for NO reduction during periodic lean-rich atmosphere

Corbos¹,

Haneda²,

Courtois³

et al. 2008

Catalysis Communications

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“…Among them, Pt-Ba/Al 2 O 3 was the mostly investigated NSR catalyst with CO, H 2 or C 3 H 6 as the reducing agent, which can provide high NO x removal efficiency (>90%) in successive sequences of lean and rich modes (Bogner et al, 1995). However, the inhibition of SO 2 is still a problem (Hodjati et al, 1998a;Schreier et al, 2005;Hammache et al 2008).…”

Section: No X Storage-reduction (Nsr)mentioning

confidence: 99%

Novel Fluidized Bed Reactor for Integrated NO_x Adsorption−Reduction with Hydrocarbons

Yang

2009

Environ. Sci. Technol.

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In order to avoid the negative impact of excessive oxygen in the combustion flue gases on the selectivity of most hydrocarbon selective catalytic reduction (HC-SCR) catalysts, an integrated NO(x) adsorption-reduction process has been proposed in this study for the treatment of flue gases under lean burn conditions by decoupling the adsorption and reduction into two different zones. The hypothesis has been validated in a novel internal circulating fluidized bed (ICFB) reactor using Fe/ZSM-5 as the catalyst and propylene as the reducing agent. Effects of propylene to the NO(x) molar ratio, flue gas oxygen concentration, and gas velocity on NO(x) conversion were studied using simulated flue gases. The results showed that increasing the ratio of HC:NO improved the reduction performance of Fe/ZSM-5 in the ICFB reactor. NO(x) conversion decreased with an increasing flue gas flow velocity in the annulus U(A) but increased with an increasing reductant gas flow velocity in the draft tube U(D). The NO(x) adsorption ratio decreased with increasing U(A). In most cases, NO(x) conversion was higher than the adsorption ratio due to the relatively poor adsorption performance of the catalyst. Fe/ZSM-5 showed a promising reduction performance and a strong inhibiting ability on the negative impact of excessive O2 in the ICFB reactor, proving that such an ICFB reactor possessed the ability to overcome the negative impact of excessive O2 in the flue gas using Fe/ZSM-5 as the deNO(x) catalyst.

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“…Most of the catalysts employing noble metals are based on Ru, Rh, Ir, − Pd, − Pt, − Au, − or Ag. − Alloys of these metals diluted into cheaper metals are used aiming at reducing the cost of the catalysts but knowing also that alloying may increase the catalytic performance due to synergic effects caused by the combination of different metals. ,,,,, The support can also have a moderate influence in the activity of the catalyst, as found by Casapu et al after thermal analysis of NO x storage and reduction on Pt/Ba/CeO 2 and Pt/Ba/Al 2 O 3 catalysts. When CeO 2 was used as a support, the catalyst exhibited inferior NO x storage and, particularly, reduction activity when compared with the Al 2 O 3 support.…”

Section: Introductionmentioning

confidence: 99%

The Role of Preadsorbed Atomic Hydrogen in the NO Dissociation on a Zigzag Stepped Gold Surface: A DFT Study

Fajín¹,

Cordeiro²,

Gomes³

2009

J. Phys. Chem. C

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NO dissociation with and without the presence of hydrogen on the Au(321) surface was investigated using density functional theory and a periodic supercell approach. The role of hydrogen in the reaction of NO dissociation is studied by comparing four different routes (i.e. direct dissociation of NO on the clean surface and paths involving reaction with hydrogen adatoms prior to N-O bond cleavage). In the latter situation, two routes via a NOH intermediate were considered, producing N* + OH* or N* + H 2 O*, and another route via a NHOH intermediate was also considered, yielding NH* and OH* species. The calculations predict that the kinetically most favorable route is that producing nitrogen adatoms and water, i.e., NO* + 2H* f N* + H 2 O* via the NOH* intermediate. This reaction is exothermic (1.1 eV) and the energy barriers for the separate NO* + H* f NOH* and NOH* + H* f N* + H 2 O* reactions are ∼0.5eV. An identical energy barrier was calculated for the reaction of the dissociation of molecular hydrogen on the stepped surface studied here, which is one-half of the barrier calculated in the case of the planar Au(111) surface. The reaction thermodynamically more favorable is that via the NHOH intermediate (1.5 eV). The kinetically least favorable path for NO dissociation on Au(321) is that occurring on the clean surface with an energy barrier of 3.5 eV; this reaction is also highly endothermic (>2.2 eV). The present work shows that the presence of hydrogen is a necessary condition for NO dissociation on this stepped surface.

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Impact of copper on the performance and sulfur tolerance of barium-based NOx storage-reduction catalysts

Cited by 16 publications

References 25 publications

Cooperative effect of Pt–Rh/Ba/Al and CuZSM-5 catalysts for NO reduction during periodic lean-rich atmosphere

Cooperative effect of Pt–Rh/Ba/Al and CuZSM-5 catalysts for NO reduction during periodic lean-rich atmosphere

Novel Fluidized Bed Reactor for Integrated NO_x Adsorption−Reduction with Hydrocarbons

The Role of Preadsorbed Atomic Hydrogen in the NO Dissociation on a Zigzag Stepped Gold Surface: A DFT Study

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Impact of copper on the performance and sulfur tolerance of barium-based NOx storage-reduction catalysts

Cited by 16 publications

References 25 publications

Cooperative effect of Pt–Rh/Ba/Al and CuZSM-5 catalysts for NO reduction during periodic lean-rich atmosphere

Cooperative effect of Pt–Rh/Ba/Al and CuZSM-5 catalysts for NO reduction during periodic lean-rich atmosphere

Novel Fluidized Bed Reactor for Integrated NOx Adsorption−Reduction with Hydrocarbons

The Role of Preadsorbed Atomic Hydrogen in the NO Dissociation on a Zigzag Stepped Gold Surface: A DFT Study

Contact Info

Product

Resources

About

Novel Fluidized Bed Reactor for Integrated NO_x Adsorption−Reduction with Hydrocarbons