Development of Low Temperature Selective Catalytic Reduction (SCR) Catalysts for Future Emissions Regulations

Ettireddy, Padmanabha R.; Kotrba, Adam; Spinks, Thomas; Boningari, Thirupathi; Smirniotis, Panagiotis G.

doi:10.4271/2014-01-1520

Cited by 19 publications

(13 citation statements)

References 29 publications

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“…As can be deduced from Figure , the reduction profiles of Mn−Ni/OMA catalysts consist of two reduction peaks around 314 and 393 °C, while the reduction profiles peaks of Mn−Ni/Al 2 O 3 catalysts appeared at 326 and 403 °C. The peak at the lower temperature might be assigned to the reduction of MnO 2 to Mn 2 O 3 and later are correlated to the reduction of Mn 2 O 3 to Mn 3 O 4 . The two steps reduction patterns were discovered for all catalysts, whereas the Mn−Ni/OMA samples indicated the shift of the position of the reduction peaks to lower temperatures, implying that the redox potential of Mn−Ni/OMA catalysts is increased compared to those of Mn−Ni/Al 2 O 3 catalysts.…”

Section: Resultsmentioning

confidence: 90%

Effect of Ordered Mesoporous Alumina Support on the Structural and Catalytic Properties of Mn−Ni/OMA Catalyst for NH₃−SCR Performance at Low‐temperature

et al. 2019

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MnÀ Ni oxides supported on ordered mesoporous alumina (OMA) catalysts were applied to the NH 3 À SCR of NO x at lowtemperature compared with MnÀ Ni oxides supported on commercial γ-Al 2 O 3 . The NO x conversion and N 2 selectivity of MnÀ Ni/OMA were superior to the MnÀ Ni/γ-Al 2 O 3 in the temperature window of 90~240°C. BET, XRD, NH 3 À TPD, NO + O 2 À TPD, Pyridine-IR, H 2 À TPR, and XPS were performed to characterized the physicochemical properties of the catalysts. The characterization results manifested that supports conduct a significant part on the structural and catalytic properties of catalysts for NH 3 À SCR performance. Compared with MnÀ Ni/Al 2 O 3 , the super SCR performances of MnÀ Ni/OMA could be ascribed to not only the higher dispersion of MnO x but also more abundant Lewis acid sites, and the increase in redox capacity since the extremely primary MnO 2 phase on catalyst's surface. Furthermore, in situ DRIFTs were conducted to detect the SCR-reaction mechanism over the two catalysts. Results demonstrate that although the OMA support can greatly enhance the catalytic activity of MnÀ Ni/OMA catalysts, the reaction mechanism over MnÀ Ni/OMA does not alter in comparison with MnÀ Ni/Al 2 O 3 . Namely, the concurrence of Langmuir-Hinshelwood (LÀ H) and Eley-Rideal (EÀ R) mechanism, among which the EÀ R mechanism plays a dominant role.[a] Dr.

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Section: Resultsmentioning

confidence: 90%

Effect of Ordered Mesoporous Alumina Support on the Structural and Catalytic Properties of Mn−Ni/OMA Catalyst for NH₃−SCR Performance at Low‐temperature

et al. 2019

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“…Three distinct reduction peaks are observed for the pure Mn/TiO 2 catalyst. The temperature reduction peaks at 364°C (T 1 ), 445°C (T 2 ), and 556°C (T 3 ) can be interpreted as a consecutive reduction of MnO 2 to Mn 2 O 3 , Mn 2 O 3 to Mn 3 O 4, and Mn 3 O 4 to MnO, respectively (Table 3) [19,20,[23][24][25].…”

Section: H 2 -Temperature-programmed Reduction (H 2 -Tpr)mentioning

confidence: 99%

Influence of elevated surface texture hydrated titania on Ce-doped Mn/TiO2 catalysts for the low-temperature SCR of NO under oxygen-rich conditions

Boningari

Ettireddy

Somogyvari

et al. 2015

Journal of Catalysis

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423

179

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“…Moreover, it exists a trade-off when operating under conventional diesel combustion (CDC) by which reducing one pollutant, the other increases [4]. Thus, current automotive diesel engines require using a selective catalyst reduction (SCR) to reduce NOx, together with a diesel particulate filter (DPF) for soot emissions [5] [6]. The addition of these elements at the exhaust line implies an increase of the production costs due to the increased complexity level as well as the operation costs due to the maintenance required and consumption of exhaust fluids needed for their operation (urea injection upwards the SCR and diesel fuel for passive DPF regenerations) [7] [8].…”

Section: Introductionmentioning

confidence: 99%

Sizing a conventional diesel oxidation catalyst to be used for RCCI combustion under real driving conditions

García

Piqueras

Monsalve‐Serrano

et al. 2018

Applied Thermal Engineering

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Reactivity controlled compression ignition (RCCI) combustion has demonstrated to be able to avoid the NOx-soot trade-off appearing during conventional diesel combustion (CDC), with similar or better thermal efficiency than CDC under a wide variety of engine platforms. However, a major challenge of this concept comes from the high hydrocarbon (HC) and carbon monoxide (CO) emission levels, which are orders of magnitude greater than CDC, and similar to those of port fuel injected (PFI) gasoline engines. The high HC and CO emissions levels combined with the low exhaust temperatures during RCCI operation could present a challenge for the current exhaust aftertreatment technologies. The objective of this work is to evaluate the potential of a conventional diesel oxidation catalyst (DOC) for light-duty diesel engines when operating under dual-fuel RCCI dieselgasoline combustion and to define its necessary size to accomplish with the current emissions standards. For this purpose, a 1-D model has been developed and calibrated through gas emissions measurements upstream and downstream the DOC under different engine steady-state conditions. After that, the DOC response in transient conditions has been evaluated by means of vehicle systems simulations under different driving cycles representative of the homologation procedures currently in force around the world. The results show that the HC and CO levels at the DOC outlet are unacceptable considering the different emissions regulations. By this reason, a dedicated study to define the DOC size needed to accomplish the different emissions standards is carried out. The results suggest that, the DOC volume needed to fulfill the type approval regulation limits ranges from four to six times the original volume.

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Development of Low Temperature Selective Catalytic Reduction (SCR) Catalysts for Future Emissions Regulations

Cited by 19 publications

References 29 publications

Effect of Ordered Mesoporous Alumina Support on the Structural and Catalytic Properties of Mn−Ni/OMA Catalyst for NH₃−SCR Performance at Low‐temperature

Effect of Ordered Mesoporous Alumina Support on the Structural and Catalytic Properties of Mn−Ni/OMA Catalyst for NH₃−SCR Performance at Low‐temperature

Influence of elevated surface texture hydrated titania on Ce-doped Mn/TiO2 catalysts for the low-temperature SCR of NO under oxygen-rich conditions

Sizing a conventional diesel oxidation catalyst to be used for RCCI combustion under real driving conditions

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Development of Low Temperature Selective Catalytic Reduction (SCR) Catalysts for Future Emissions Regulations

Cited by 19 publications

References 29 publications

Effect of Ordered Mesoporous Alumina Support on the Structural and Catalytic Properties of Mn−Ni/OMA Catalyst for NH3−SCR Performance at Low‐temperature

Effect of Ordered Mesoporous Alumina Support on the Structural and Catalytic Properties of Mn−Ni/OMA Catalyst for NH3−SCR Performance at Low‐temperature

Influence of elevated surface texture hydrated titania on Ce-doped Mn/TiO2 catalysts for the low-temperature SCR of NO under oxygen-rich conditions

Sizing a conventional diesel oxidation catalyst to be used for RCCI combustion under real driving conditions

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Effect of Ordered Mesoporous Alumina Support on the Structural and Catalytic Properties of Mn−Ni/OMA Catalyst for NH₃−SCR Performance at Low‐temperature

Effect of Ordered Mesoporous Alumina Support on the Structural and Catalytic Properties of Mn−Ni/OMA Catalyst for NH₃−SCR Performance at Low‐temperature