NOx Storage Reduction over PtBa/γ-Al2O3 Catalyst

Lietti, Luca; Forzatti, Pio; Nova, Isabella; Tronconi, Enrico

doi:10.1006/jcat.2001.3370

Cited by 344 publications

(281 citation statements)

References 13 publications

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“…Catalysts were prepared via wet impregnation of the supports using the procedure described in [11]. Commercial c-Al 2 O 3 (BET surface area 210 m 2 /g), SiO 2 (200 m 2 /g) and ZrO 2 (60 m 2 /g) were impregnated with precursor solutions of Pt(NH 3 ) 2 (NO 2 ) 2 and Ba(CH 3 COO) 2 to a final loading of active metals of 1 wt% Pt and 17 wt% Ba.…”

Section: Methodsmentioning

confidence: 99%

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Role of Support in Lean DeNO_xCatalysis

Piacentini

Maciejewski

Bürgi

et al. 2004

Topics in Catalysis

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FTIR and pulse thermal analysis were applied to investigate catalysts containing Pt (1 wt%)/Ba (17 wt%) supported on c-Al 2 O 3 , SiO 2 and ZrO 2 . The aim was to learn how the support material affects the thermal stability of barium carbonate and its activity in the reaction to bulk Ba(NO 3 ) 2 . The lower thermal stability of BaCO 3 in alumina supported samples was found to influence the formation of barium nitrate during the NO x storage process. Quantification of Ba(NO 3 ) 2 formed during NO x storage indicated that for alumina supported catalysts only ca. 30% of barium present in the sample is involved in the storage process. The low thermal stability found for alumina supported barium nitrite excludes its role in the formation of barium nitrate during interaction of NO x with the catalyst at 300°C. The studies indicate that c-Al 2 O 3 plays a major role in influencing the thermal stability of BaCO 3 and Ba(NO 3 ) 2 . This finding seems to be relevant for the higher activity of c-Al 2 O 3 -supported catalysts in NO x storage reduction reactions. KEY WORDS:Lean DeNO x ; BaCO 3 ; Ba(NO 3 ) 2 and Ba(NO 2 ) 2 thermal stability; pulse thermal analysis; role of the support in NO x storage.

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Section: Methodsmentioning

confidence: 99%

“…In situ FTIR studies were performed by several authors [5][6][7][8][9][10][11] showing the formation of both nitrite and nitrate species during storage of NO/O 2. Li et al [12] stated that the higher the adsorption temperature, the higher is the concentration of nitrate compared to nitrite.…”

Section: Introductionmentioning

confidence: 99%

Role of Support in Lean DeNO_xCatalysis

Piacentini

Maciejewski

Bürgi

et al. 2004

Topics in Catalysis

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“…Most of previous studies have focused on catalyst compositions and operating conditions that have a great impact on the performance of NO x storage and reduction [7][8][9][10][11][12][13]. For Ba-containing catalysts, noble metal species and their dispersion can lead to different NO oxidation activity during the lean phase [8,14,15] thus directly influencing subsequent adsorption on Ba sites.…”

Section: Introductionmentioning

confidence: 99%

“…For Ba-containing catalysts, noble metal species and their dispersion can lead to different NO oxidation activity during the lean phase [8,14,15] thus directly influencing subsequent adsorption on Ba sites. Additionally, as a result of different preparation methods and reaction conditions, Ba can be present in the form of BaO, Ba(OH) 2 , or BaCO 3 , with NO x adsorption ability showing a decreased order [9]. Furthermore, Ba sites located in proximity to Pt play an important role during the trap process.…”

Section: Introductionmentioning

confidence: 99%

Effect of Co addition to Pt/Ba/Al2O3 system for NOx storage and reduction

Wang

2010

Applied Catalysis B: Environmental

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a b s t r a c tA comparative study of Pt/Ba/Al 2 O 3 , Co/Ba/Al 2 O 3 , Pt/Co/Al 2 O 3 and Pt/Co/Ba/Al 2 O 3 was performed in regards to their NO x storage capacities and NO oxidation abilities as a function of temperature. The nitrate stability and dynamic behaviors of NO x storage reduction during lean/rich fuel cycles using hydrogen as a reductant were also investigated over these catalysts. It was found that Pt/Co/Ba/Al 2 O 3 possessed the largest NO x storage capacity within the temperature range of 200-350 • C. The existence of Co not only improved the oxidation of NO to NO 2 under lean conditions, but also enhanced the release and reduction of NO x during the rich phase. The Pt and Co co-supported catalysts showed better NO x storage reduction activity and higher N 2 selectivity than Pt supported Ba/Al 2 O 3 catalysts within the tested temperature range. As for Pt/Co/Ba/Al 2 O 3 , high conversion was obtained at either a low reductant concentration with long duration time or a high reductant concentration with short duration time during the rich phase. In situ FTIR studies showed that NO x adsorption over Co-containing catalysts takes "nitrite route" as an important pathway. The intimate contact of Co and Ba/Al could accelerate nitrite/nitrate formation and the synergistic effect of Pt and Co could accelerate NO x reduction.

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“…Depending on the surrounding gas-phase the catalyst may need an initiation time to reach the state of catalytic activity such as in FischerTropsch catalysts [20]. The catalyst may also store certain gaseous components and release them upon modified conditions in the gas-phase such as NO x storage catalysts [21,22]. Adsorbed species can undergo structural changes leading to undesired deposits such as carbonaceous overlayers, e.g.…”

Section: Introductionmentioning

confidence: 99%

Modeling of the Interactions Between Catalytic Surfaces and Gas-Phase

Deutschmann

2014

Catal Lett

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The catalytic surface interacts with the gasphase by a variety of chemical and physical processes. Hence, optimization of design and operation conditions of catalytic reactors do not only require the understanding of the catalytic reaction sequence but also its coupling with mass and heat transport and potential homogeneous reactions. The chemical, thermal, and mass-transport interactions between the catalytic surface and the gas-phase are discussed in terms of the individual and combined interactions. The state-of-the-art modelling of reactive flows and its coupling with the catalytic surface is summarized. The interactions are illustrated by a number of examples such as reforming of hydrocarbons, catalytic combustion, exhaust-gas after-treatment, each focusing on a special aspect of catalyst-gas interactions. The potentials and limitations of the numerical simulations will be discussed including experimental techniques for model validation.

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NOx Storage Reduction over PtBa/γ-Al2O3 Catalyst

Cited by 344 publications

References 13 publications

Role of Support in Lean DeNO_xCatalysis

Role of Support in Lean DeNO_xCatalysis

Effect of Co addition to Pt/Ba/Al2O3 system for NOx storage and reduction

Modeling of the Interactions Between Catalytic Surfaces and Gas-Phase

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NOx Storage Reduction over PtBa/γ-Al2O3 Catalyst

Cited by 344 publications

References 13 publications

Role of Support in Lean DeNOxCatalysis

Role of Support in Lean DeNOxCatalysis

Effect of Co addition to Pt/Ba/Al2O3 system for NOx storage and reduction

Modeling of the Interactions Between Catalytic Surfaces and Gas-Phase

Contact Info

Product

Resources

About

Role of Support in Lean DeNO_xCatalysis

Role of Support in Lean DeNO_xCatalysis