Controlling the selectivity to N2O over Pt/Ba/Al2O3 NOX storage/reduction catalysts

Elizundia, U.; Divakar, D.; Pereda‐Ayo, Beñat; López‐Fonseca, Rubén; González‐Velasco, Juan R.

doi:10.1016/j.cattod.2010.11.075

Cited by 24 publications

(15 citation statements)

References 19 publications

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“…It is generally admitted that the N2O formation over precious metals comes from the recombination of atomic N (from the NO dissociative adsorption on metallic platinum sites) with adsorbed NO [33]. In NSR cycles, N2O was reported to be especially detected during the lean/rich switches, due to a lack in metal reduction [34]. Results reported above in this study show that the composition of the rich and lean gas mixtures dramatically modifies the catalytic results.…”

Section: Influence Of Reductant(s) In the Lean Phases On The N2o Formationmentioning

confidence: 50%

“…The effect of various reducing agent (H2, CO, C3H6) on the efficiency and selectivity of NSR catalysts was already studied on platinum supported on alumina-based oxides [15,26,27], but usually with simplified mixtures. Using CO or C3H6 as reducing agents, authors have reported that significant N2O emission occurs rather at low temperature (i.e.…”

Section: Influence Of the Nature Of The Reductant On The Nox Conversion And Selectivitymentioning

confidence: 99%

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Effect of reducing agent (C3H6, CO, H2) on the NOx conversion and selectivity during representative lean/rich cycles over monometallic platinum-based NSR catalysts. Influence of the support formulation

Masdrag¹,

Courtois²,

Can³

et al. 2014

Applied Catalysis B: Environmental

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NOx storage reduction efficiency was investigated on a Pt-10%BaO/Al2O3 model catalyst using a complex gas feed including reductants and oxidants in both lean and rich mixtures. Three representative reductants have been studied, separately and blended: C3H6, CO, H2 and C3H6+CO+H2. The influence of each reductant was evaluated with a special consideration to the N2O selectivity. The reductant /oxidant ratio was kept constant for the lean and the rich gas mixture, respectively. The N2O emission depends on the introduced reductant(s), and the nature of reductant acts differently depending on the temperature. At 200°C, H2 mainly drives the N2O emission, whereas at 300°C, N2O yields is enhanced by C3H6. In addition, it is demonstrated that NOx reduction also occurs during the lean period, leading to significant amount of N2O. In fact, on Pt-10%BaO/Al2O3 catalyst, 70 to 90% of the produced N2O come from the lean phase, except with CO as reductant which does not allow any NOx reduction in lean condition. Results were compared with a platinum/ceria-zirconia-based oxide (Pt/CZ) previously studied. Pt/CZ is generally more active at low temperature (200°C). At 300°C, significant differences appear between the two formulations depending on the used reductant, especially concerning the Ncompound selectivities in the rich pulses.

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Section: Influence Of Reductant(s) In the Lean Phases On The N2o Formationmentioning

confidence: 50%

Section: Influence Of the Nature Of The Reductant On The Nox Conversion And Selectivitymentioning

confidence: 99%

Effect of reducing agent (C3H6, CO, H2) on the NOx conversion and selectivity during representative lean/rich cycles over monometallic platinum-based NSR catalysts. Influence of the support formulation

Masdrag¹,

Courtois²,

Can³

et al. 2014

Applied Catalysis B: Environmental

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show abstract

“…e-Other aspects should be considered such as the formation of N2O 15,16 which should be minimized due to its very powerful greenhouse effect, or the formation of NH3 which should benefit for the whole NOx reduction. NH3 selectivity is clearly related to the presence of H2 in the rich gas 17 but also depends on H2O and CO2 concentration due to the reverse-water gas shift reaction (CO2+H2  CO + H2O) which generates a certain amount of CO. 18 Finally, it was proven that coupling NSR and SCR materials presents great advantage, the SCR catalysts allowing a supplementary conversion of NOx thanks to ammonia formed in the NSR process.…”

Section: Requirements For Nsr Catalytic Materialsmentioning

confidence: 99%

Chapter 3. NSR Catalytic Materials

Can¹,

Courtois²,

Duprez³

2018

Catalysis Series

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Imagined in the 90's, the NOx-storage and reduction (NSR) process operates with alternative cycles of long lean phases (NOx storage) and short rich phases (NOx reduction). NSR catalysts should possess at least two components: a basic oxide for trapping the NOx and a metallic component for the NO oxidation and the reduction of stored NOx. The reference material is composed of barium oxide (10-20 wt-%) deposited on a Pt/Al2O3 (1-2 % Pt). Improvements of NSR catalysts were obtained by changing (i) the basic component (especially potassium but it can also damage the catalyst substrate; other alkaline or alkaline-earth oxides were also envisaged); (ii) the support (especially cerium-based supports, or titania, hydrotalcites, perovskites); (iii) the metal (Rh is often added to improve the NOx reduction, and combinations of precious metals are considered). Noble metal-free catalysts were also developed, mainly based on cobalt, copper or manganese oxides. Perovskites including these transition metal oxides and potassium are also interesting for NSR applications. However, complete replacement of noble metal catalysts cannot be feasible yet. Usual NSR catalysts are sensitive to aging (sintering; strong of Ba-support interactions) and to sulphur poisoning but supports like TiO2 or cerium-based oxides can protect the catalyst from stable sulphate adsorption.

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“…The catalytic reduction of NO has gained much attention in recent years, [3][4][5][6][7] due to its high efficiency, selectivity and simplicity. Previous studies [8][9][10][11][12][13][14] have indicated that NO could be converted into N 2 O, N 2 or NO 2 species in the presence of CO as the reducing agent. This is promising, since it also provides a route for removing toxic CO from the atmosphere.…”

Section: Introductionmentioning

confidence: 99%

NO reduction over an Al-embedded MoS₂ monolayer: a first-principles study

Esrafili

Heydari

2019

RSC Adv.

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Controlling the selectivity to N2O over Pt/Ba/Al2O3 NOX storage/reduction catalysts

Cited by 24 publications

References 19 publications

Effect of reducing agent (C3H6, CO, H2) on the NOx conversion and selectivity during representative lean/rich cycles over monometallic platinum-based NSR catalysts. Influence of the support formulation

Effect of reducing agent (C3H6, CO, H2) on the NOx conversion and selectivity during representative lean/rich cycles over monometallic platinum-based NSR catalysts. Influence of the support formulation

Chapter 3. NSR Catalytic Materials

NO reduction over an Al-embedded MoS₂ monolayer: a first-principles study

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Controlling the selectivity to N2O over Pt/Ba/Al2O3 NOX storage/reduction catalysts

Cited by 24 publications

References 19 publications

Effect of reducing agent (C3H6, CO, H2) on the NOx conversion and selectivity during representative lean/rich cycles over monometallic platinum-based NSR catalysts. Influence of the support formulation

Effect of reducing agent (C3H6, CO, H2) on the NOx conversion and selectivity during representative lean/rich cycles over monometallic platinum-based NSR catalysts. Influence of the support formulation

Chapter 3. NSR Catalytic Materials

NO reduction over an Al-embedded MoS2 monolayer: a first-principles study

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NO reduction over an Al-embedded MoS₂ monolayer: a first-principles study