Outstanding low temperature HC-SCR of NOx over platinum-group catalysts supported on mesoporous materials expecting diesel-auto emission regulation

Komatsu, Toshimitsu; Tomokuni, Keizou; Yamada, Issaku

doi:10.1016/j.cattod.2006.01.035

Cited by 29 publications

(16 citation statements)

References 13 publications

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“…The present zeolites are not solid bases, such as BaO usually used as LNT-agents, therefore, the materials have no problems such as deactivation with several ppm SOx (SOx poisoning or stoichiometric sufation). Zeolites, such as HZSM-5 and MCM-41, produce low-temperature activities in the catalyst, as previously reported (Komatsu et al, 2006). These results strongly suggest that the support effect is due to the incorporated metals.…”

Section: The Support Effect On Nox-conversion Vs Temperature Profilesupporting

confidence: 85%

“…The silica/metal atom ratio was adjusted to 20/1. The experimental details were described in the previous report (Komatsu et al, 2006). The Pt-catalyst supported on MPS (Pt/MPS) and on the silicates (Pt/metal-silicate) were prepared by impregnating each support-material with an aqueous solution of H 2 PtCl 4 and RhCl 3 ·3H 2 O, evaporated to dryness at 110 , followed by reduction with hydrogen at 300 for 1 h. The precious metal loading of the Pt-catalysts was adjusted at a 5 mass % Pt-0.3 mass % Rh.…”

Section: Sample Preparationmentioning

confidence: 99%

“…We have previously reported the low-temperature active Pt/MPS (platinum-catalyst supported on mesoporous silica) (Komatsu et al, 2006(Komatsu et al, , 2010. This paper describes a prototype Pt/MPS coated honeycomb for practical applications to remove the diesel-NOx.…”

Section: Introductionmentioning

confidence: 99%

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Low-Temperature Active Pt-catalysts Supported on Mesoporous Silica and Metal-Silicates for Cleaning Diesel-NOx Exhausts

Komatsu¹,

Tomokuni²,

Konishi³

et al. 2012

IJC

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New Pt-catalysts supported on mesoporous silica (MPS) and metal-silicates, which have high de-NOx capabilities over 70 % in NOx-conversion at temperatures around 170 under lean conditions, were developed. A new prototype honeycomb supporting Pt-catalyst allows high de-NOx of diesel-exhausts possible over the wide temperature range of 170-400 . The low-temperature activities of the catalysts are well correlated with the Brønsted acidity of the support materials. In view of the reaction mechanism of the de-NOx processes, the Brønsted acid-sites of the supports probably stimulate the oxidation of NO into NO 2 , which is the rate-determining step of de-NOx processes, leading to the low-temperature activities.

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Section: The Support Effect On Nox-conversion Vs Temperature Profilesupporting

confidence: 85%

Section: Sample Preparationmentioning

confidence: 99%

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Low-Temperature Active Pt-catalysts Supported on Mesoporous Silica and Metal-Silicates for Cleaning Diesel-NOx Exhausts

Komatsu¹,

Tomokuni²,

Konishi³

et al. 2012

IJC

Self Cite

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“…This research is focused on HC-SCR which could eliminate the need for a secondary fuel tank [8]- [12] and the use of expensive platinum group metal (pgm) loadings. A hydrocarbon (HC) containing reactant is injected into the exhaust gas upstream the HC-SCR catalyst and those hydrocarbons then react with the NOx on the catalyst's active sites to reduce the NOx levels downstream the catalysis.…”

Section: Introductionmentioning

confidence: 99%

Enhancing selective catalytic reduction of NOx with alternative reactants/promoters

Herreros

George

Umar

et al. 2014

Chemical Engineering Journal

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The hydrocarbon-selective catalytic reduction (HC-SCR) activity of an Ag/Al 2 O 3 catalyst was investigated. The function on catalytic NOx reduction of different fuel properties using alternative reactants such as gas-to-liquid (GTL) and butanol was studied. This work proves that such improvements are due to the high reactivity, polarity and diffusivity of butanol within the catalyst enhancing NOx conversion. Furthermore, it is suggested that HC components such butanol share some of the reaction mechanisms to hydrogen as a promoter in addition to his role as a reductant leading to improve NOx reduction. Therefore, it is proposed the simultaneous dual role of butanol as a reactant and as promoter.Catalyst performance at low temperature was further improved with the addition of hydrogen (H 2 ).However, this performance was found to degrade as temperature increases, due to H 2 reactant selectivity changing, directly being oxidised. Increased NOx conversion was dependent on HC:NOx ratio, showing at low temperature a low HC:NOx ratio is required. As temperature increases, so does the required HC:NOx ratio to compensate for hydrocarbons partial and complete oxidation. These results demonstrate a method of gaining significant NOx reduction through the combination of environmental catalysts and alternative reactants.

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“…Figure 6a, b shows the NO x conversion and N 2 selectivity, respectively, of the 0.2 wt% Pd/(60+20)−20 and 0.05 wt% Pd/(60+20)−20 catalysts tested before and after aging. The aging procedure simulated at least 80,000 km of on-road usage [44]. The maximum NO x conversion of 0.05 wt% Pd/ (60+20)−20 shifted to higher temperature and decreased from approximately 90 % at 200°C to circa 51 % at 310°C after aging.…”

Section: Aged Catalystsmentioning

confidence: 99%

Influence of Supports on Pd Catalysts for the Selective Catalytic Reduction of NOx with H2 and CO

Caravaggio

Nossova

Burich

2015

Emiss. Control Sci. Technol.

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A major concern of current commercial catalysts for the selective catalytic reduction (SCR) of nitrogen oxides (NO x ) (DeNO x ) is the lack of sufficient catalytic activity at low temperatures (below 200°C) that typically occur during cold start and urban driving conditions. To address this issue, a study was undertaken to develop an (H 2 + CO)-SCR Pd-based catalyst to obtain high DeNO x activity in this low-temperature range. A series of catalysts with Pd loaded on supports containing various amounts of γ-alumina (γ-Al 2 O 3 ) (0-65 wt%), CBV-2314 (15-100 wt%), and TiO 2 (0-20 wt%) were tested for DeNO x activity and aging in a catalyst testing unit (CTU). The results showed that each component in the support played a role in the NO x conversion, depending on the temperature. Catalysts with Pd supported on {[γ-Al 2 O 3 (60 wt%)+CBV-2314 (20 wt%)]-TiO 2 (20 wt%)} achieved the best overall DeNO x activity. Catalysts with various Pd loadings (0.05 wt% to 0.5 wt%) were prepared with a {[γ-Al 2 O 3 (60 wt%)+CBV-2314 (20 wt%)]−TiO 2 (20 wt%)} support. The catalysts loaded with 0.05 wt% and 0.2 wt% Pd demonstrated the best overall DeNO x activity (up to 90 % NO x conversion starting at 150°C). These catalysts were subjected to an accelerated aging regime. Based on the aging studies, the 0.2 wt% Pd/{[γ-Al 2 O 3 (60 wt%)+CBV-2314 (20 wt%)]− TiO 2 (20 wt%)} composition was the most active and stable catalyst.

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Outstanding low temperature HC-SCR of NOx over platinum-group catalysts supported on mesoporous materials expecting diesel-auto emission regulation

Cited by 29 publications

References 13 publications

Low-Temperature Active Pt-catalysts Supported on Mesoporous Silica and Metal-Silicates for Cleaning Diesel-NOx Exhausts

Low-Temperature Active Pt-catalysts Supported on Mesoporous Silica and Metal-Silicates for Cleaning Diesel-NOx Exhausts

Enhancing selective catalytic reduction of NOx with alternative reactants/promoters

Influence of Supports on Pd Catalysts for the Selective Catalytic Reduction of NOx with H2 and CO

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