Selective Catalytic Reduction of NO<sub>x</sub> with NH<sub>3</sub> on Cu-, Fe-, and Mn-Zeolites Prepared by Impregnation: Comparison of Activity and Hydrothermal Stability

Putluru, Siva Sankar Reddy; Schill, Leonhard; Jensen, Anker Degn; Fehrmann, Rasmus

doi:10.1155/2018/8614747

Cited by 27 publications

(12 citation statements)

References 49 publications

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“…There was one broad peak spanned within the temperature range of 200°C to 500°C for these three catalysts, which was corresponded to the successive reduction steps of MnO x and the reduction of Ce 4+ : MnO 2 → Mn 2 O 3 → Mn 3 O 4 → MnO and Ce 4+ → Ce 3+. The reduction peak temperature (T red ) of MDP3 and DP2 was 345°C and 343°C, respectively, which were much smaller than that of 1IMP1. Liu et al believed that the lower T red is, the stronger is the redox ability of catalysts.…”

Section: Resultsmentioning

confidence: 89%

Enhancement of SCR performance of monolithic Mn–Ce/Al₂O₃/cordierite catalysts by using modified deposition precipitation method

Quan

et al. 2019

Asia-Pacific J Chem Eng

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Mn-Ce catalysts have been widely studied for low-temperature selective catalytic reduction (SCR) of NO x with NH 3 ; however, most of them are powdery or granular. Monolithic catalysts which are more suitable for practical industrial applications still need detailed exploration. In this research, a series of monolithic Mn-Ce/Al 2 O 3 /cordierite catalysts were prepared by impregnation (IMP), deposition precipitation (DP), and modified deposition precipitation (MDP) methods. The catalyst MDP3 which depositing alumina and MnO x -CeO x simultaneously for three times by MDP method showed the best activity, and it performed much better at low temperature than the catalysts prepared by IMP and DP methods. MDP3 also showed the best resistance to H 2 O and SO 2 . It was thought that Mn-Al and Mn-Al-Ce clusters formed in the preparation of MDP3 and enhanced the interaction between the mixed oxides, as indicated by the characterization results. MDP3 prepared by MDP method showed the largest BET surface area, good redox capabilities, and the highest atomic ratios of Ce 3+ and O b . Hence, MDP was proved to be an effective method to enhance the interaction between the washcoat and the active phase, which resulted in preparing a good performance monolithic SCR catalyst.

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Section: Resultsmentioning

confidence: 89%

Enhancement of SCR performance of monolithic Mn–Ce/Al₂O₃/cordierite catalysts by using modified deposition precipitation method

Quan

et al. 2019

Asia-Pacific J Chem Eng

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“…According to the high copper content, the excess amount of copper is detected as CuO when the exchange sites have been involved. One primary peak of the Fe/ZSM-5 catalyst at around 470°C ascribes to the reduction of Fe 3+ to Fe 2+ at zeolite ion-exchange positions [36,37] as well as the reduction of Fe 2 O 3 to Fe 3 O 4 [38]. Also, a small and broad peak attended at approximately 630°C, which can refer to the reduction of Fe 3 O 4 to FeO [39] and a residual fraction of framework Fe 3+ that is hardly reduced [40].…”

Section: Chemisorption Resultsmentioning

confidence: 97%

Hybrid Cu-Fe/ZSM-5 Catalyst Prepared by Liquid Ion-Exchange for NOx Removal by NH3-SCR Process

Doan

Dang

Nguyen

et al. 2021

Journal of Chemistry

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A series of Cu/ZSM-5, Fe/ZSM-5, and Cu-Fe/ZSM-5 catalysts (Si/Al in ZSM-5 = 25) were prepared by different metal loadings using the liquid ion-exchange method. Several characterization methods were conducted to explore the effects of metals on the physical and chemical properties of catalysts. Meanwhile, the electron paramagnetic resonance method is also used to assess the copper and/or iron elements’ coordination and valence state at intersections or in channels of ZSM-5. The metal-loading effects of all catalysts on the catalytic activities were studied for the removal of NOx in a fixed-bed flow reactor using selective catalytic reduction with ammonia (NH3-SCR). The results showed that the iron’s addition could markedly broaden the operation temperature range of the Cu/ZSM-5 catalyst for NH3-SCR between 200 and 550°C due to the presence of more isolated Cu2+ ions as well as additional oligomeric Fe3+ active sites and FexOy oligomeric species. This paper gives a facile and straightforward way to synthesize the practical-promising catalyst applied in NH3-SCR technology to control NOx emissions.

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“…The H 2 -TPR profiles were collected, and a peak fitting for all samples was conducted, the results of which are presented in Figure . Research about Cu-zeolites proved that Cu species is copper cations or nanosized polynuclear oxidations in zeolites . The fresh samples show five reduction peaks between 200 and 800 °C as well as the aged samples.…”

Section: Resultsmentioning

confidence: 99%

One-Pot Synthesis of the Cu-SAPO-18 Catalyst Using Waste Mother Liquid and its Application in the SCR of NO_x with NH₃

Guo

Ming

Zhang

et al. 2020

Ind. Eng. Chem. Res.

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A green and efficient way of synthesizing Cu-SAPO-18 was developed, which is characterized by the one-pot method and recycling of the mother liquid. All fresh samples synthesized with or without the mother liquid exhibit similar structural properties, Si/(P + Al), and particle sizes. However, all fresh catalysts show some differences in Brunauer−Emmett−Teller surface areas, Cu content, roughness of the crystal surface, and Si coordination. Temperature-programed desorption of ammonia, 29 Si magic angle spinning nuclear magnetic resonance, temperature-programmed reduction experiments by H 2 , electron paramagnetic resonance, and UV−vis-diffuse reflectance spectroscopy results suggest that the mother liquid declines the content of acid sites, Cu 2+ and CuO of Cu-18-0.5 and Cu-18-1. Therefore, Cu-18-0.5 and Cu-18-1 exhibit a decline in low-temperature activity but an increase in high-temperature activity, compared to Cu-18-0. During aging treatment, the mother liquid contributes to the movement of CuO to ion-exchange sites and new isolated Cu 2+ ions are generated. However, excess mother liquid causes severe structural damage of Cu-18-1. Finally, Cu-18-0.5 exhibits the best hydrothermal stability owing to the more active Cu 2+ sites and less structural collapse.

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Selective Catalytic Reduction of NO_x with NH₃ on Cu-, Fe-, and Mn-Zeolites Prepared by Impregnation: Comparison of Activity and Hydrothermal Stability

Cited by 27 publications

References 49 publications

Enhancement of SCR performance of monolithic Mn–Ce/Al₂O₃/cordierite catalysts by using modified deposition precipitation method

Enhancement of SCR performance of monolithic Mn–Ce/Al₂O₃/cordierite catalysts by using modified deposition precipitation method

Hybrid Cu-Fe/ZSM-5 Catalyst Prepared by Liquid Ion-Exchange for NOx Removal by NH3-SCR Process

One-Pot Synthesis of the Cu-SAPO-18 Catalyst Using Waste Mother Liquid and its Application in the SCR of NO_x with NH₃

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Selective Catalytic Reduction of NOx with NH3 on Cu-, Fe-, and Mn-Zeolites Prepared by Impregnation: Comparison of Activity and Hydrothermal Stability

Cited by 27 publications

References 49 publications

Enhancement of SCR performance of monolithic Mn–Ce/Al2O3/cordierite catalysts by using modified deposition precipitation method

Enhancement of SCR performance of monolithic Mn–Ce/Al2O3/cordierite catalysts by using modified deposition precipitation method

Hybrid Cu-Fe/ZSM-5 Catalyst Prepared by Liquid Ion-Exchange for NOx Removal by NH3-SCR Process

One-Pot Synthesis of the Cu-SAPO-18 Catalyst Using Waste Mother Liquid and its Application in the SCR of NOx with NH3

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Product

Resources

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Selective Catalytic Reduction of NO_x with NH₃ on Cu-, Fe-, and Mn-Zeolites Prepared by Impregnation: Comparison of Activity and Hydrothermal Stability

Enhancement of SCR performance of monolithic Mn–Ce/Al₂O₃/cordierite catalysts by using modified deposition precipitation method

Enhancement of SCR performance of monolithic Mn–Ce/Al₂O₃/cordierite catalysts by using modified deposition precipitation method

One-Pot Synthesis of the Cu-SAPO-18 Catalyst Using Waste Mother Liquid and its Application in the SCR of NO_x with NH₃