Enhanced low-temperature NH 3 -SCR performance of MnO x /CeO 2 catalysts by optimal solvent effect

Yao, Xin‐Kan; Kong, Tingting; Chen, Li; Ding, Shimin; Yang, Fumo; Dong, Lin

doi:10.1016/j.apsusc.2017.05.156

Cited by 100 publications

(33 citation statements)

References 39 publications

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“…Another method is to improve the preparation method of the Mn-based catalyst. Yao et al [21] found that the MnO 2 -based catalyst prepared by impregnation method in acetic acid solvent shows better SCR activity and SO 2 resistance than in deionized water, anhydrous ethanol, and oxalic acid, owing to the evenly dispersed MnO x and enhanced interaction between metal oxides. Yu et al [22] investigated the effect of Fe addition into Mn/TiO 2 catalyst via sol-gel and impregnation methods and they reported that the promotion of SO 2 resistance is related to the catalyst structure rather than the catalyst's components.In the present work, the Cu-Mn/SAPO-34 zeolite catalysts were prepared by impregnation method.…”

mentioning

confidence: 99%

Effect of Transition Metal Additives on the Catalytic Performance of Cu–Mn/SAPO-34 for Selective Catalytic Reduction of NO with NH3 at Low Temperature

Liu

Zhang

et al. 2019

Catalysts

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The adsorption of NO, NH 3 , H 2 O, and SO 2 gaseous molecules on different transition metal oxides was studied based on density function theory (DFT), and three better-performing transition metal elements (Fe, Co, and Ce) were selected. Cu-Mn/SAPO-34 catalysts were prepared by impregnation method and then modified by the selected transition metals (Fe, Co, and Ce); the SO 2 resistance experiments and characterizations including Brunner−Emmet−Teller (BET), X-ray Diffraction (XRD), Scanning Electronic Microscopy (SEM), and thermal gravity analysis (TG)-differential thermal gravity (DTG) before and after SO 2 poisoning were conducted. The results showed that the deactivation of the Cu-Mn/SAPO-34 catalyst is ascribed to the deposition of lots of ammonium sulfates on the surface, depositing on the active sites and inhibiting the adsorption of NH 3 . After the modification of Fe, Co, and Ce oxides, the SO 2 resistance of the modified Cu-Mn/SAPO-34 catalyst was significantly enhanced due to the less formation of ammonium sulfates. Among all these modified Cu-Mn/SAPO-34 catalysts, the Cu-Mn-Ce/SAPO-34 exhibited the highest SO 2 resistance owing to the decreased decomposition temperature and the trapper of ceria for capturing SO 2 to form Ce(SO 4 ) 2 , further inhibiting the deposition of ammonium sulfates.Catalysts 2019, 9, 685 2 of 15 be an important oxide component in the SCR reaction, due to the various types of labile oxygen and high oxygen-storage capacity [9]. CuO is found to be highly resistant to SO 2 in the low-temperature SCR reaction due to the activity of CuSO 4 [10]. It is reported that the Mn-Cu/SAPO-34 catalyst displays remarkable hydrothermal stability and good SCR activity in a broad temperature range [11][12][13].It is well accepted that the application of low-temperature SCR catalyst relies not only on the high SCR activity, but also the superior SO 2 resistance due to the fact that the exhaust from the industrial boiler system contains a good amount of SO 2 . However, Mn-based catalysts are proven to be sensitive to SO 2 poisoning. Two main deactivation routes are widely reported. Firstly, SO 2 can be oxidized to SO 3 , which can react with NH 3 and H 2 O to form (NH 4 ) 2 SO 4 and NH 4 HSO 4 ; the former dries powdery, which decomposes at 280 • C [14], but the latter is a kind of corrosive and sticky substance, which decomposes at 390 • C [15], Secondly, MnO x or CuO may react with SO 2 to form stable sulfate species, which can cut off the redox cycle of the catalyst [16] and hinder the adsorption and activation of NO on the surface of the catalyst [17]. As such, the development of Mn-based catalysts with superior SO 2 resistance has attracted wide concern by many researchers.The main method to improve SO 2 resistance is adding other modification metals/non-metals to SCR catalyst. Chang et al. [18] reported that the NO conversion over the SnO x -MnO 2 -CeO 2 catalyst exhibited 60% approximately in the presence of SO 2 and H 2 O, which is much higher than that over MnO 2 -CeO 2 . The promotion effect...

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confidence: 99%

Effect of Transition Metal Additives on the Catalytic Performance of Cu–Mn/SAPO-34 for Selective Catalytic Reduction of NO with NH3 at Low Temperature

Liu

Zhang

et al. 2019

Catalysts

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“…Yao et al successfully prepared a series of Mn/CeO2 catalysts via impregnation using deionized water, anhydrous ethanol, acetic acid, and oxalic acid as a solvent and found that Mn/Ce-OA (oxalic acid) exhibited the best water and sulfur tolerance among all catalysts ( Figure 6) [26]. Chen et al [10] found that the SO2 tolerance of MnOx was dramatically enhanced by the introduction of Cr due to the formation of CrMn1.5O4.…”

Section: Mn-based Binary Metal Oxide Catalystsmentioning

confidence: 99%

“…presented a noticeable decrease in the catalytic activity for the NOx conversion at 100 °C in the presence of H2O and SO2 ( Figure 5), a slight inhibiting effect was observed from 150 to 200 °C, and the promoting effect was exhibited above 200 °C [25]. Yao et al successfully prepared a series of Mn/CeO2 catalysts via impregnation using deionized water, anhydrous ethanol, acetic acid, and oxalic acid as a solvent and found that Mn/Ce-OA (oxalic acid) exhibited the best water and sulfur tolerance among all catalysts ( Figure 6) [26]. Chen et al [10] found that the SO2 tolerance of MnOx was dramatically enhanced by the introduction of Cr due to the formation of CrMn1.5O4.…”

Section: Mn-based Binary Metal Oxide Catalystsmentioning

confidence: 99%

Sulfur and Water Resistance of Mn-Based Catalysts for Low-Temperature Selective Catalytic Reduction of NOx: A Review

et al. 2018

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Selective catalytic reduction (SCR) with NH 3 is the most efficient and economic flue gas denitrification technology developed to date. Due to its high low-temperature catalytic activity, Mn-based catalysts present a great prospect for application in SCR de-NO x at low temperatures. However, overcoming the poor resistance of Mn-based catalysts to H 2 O and SO 2 poison is still a challenge. This paper reviews the recent progress on the H 2 O and SO 2 resistance of Mn-based catalysts for the low-temperature SCR of NO x . Firstly, the poison mechanisms of H 2 O and SO 2 are introduced in detail, respectively. Secondly, Mn-based catalysts are divided into three categories-single MnO x catalysts, Mn-based multi-metal oxide catalysts, and Mn-based supported catalysts-to review the research progress of Mn-based catalysts for H 2 O and SO 2 resistance. Thirdly, several strategies to reduce the poisonous effects of H 2 O and SO 2 , such as metal modification, proper support, the combination of metal modification and support, the rational design of structure and morphology, are summarized. Finally, perspectives and future directions of Mn-based catalysts for the low-temperature SCR of NO x are proposed.

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“…[24][25][26][27] Excellent H 2 O tolerance levels and high thermal stability have been obtained in novel MnFeO x nanorods and Mn 2 O 3 -doped Fe 2 O 3 hexagonal microsheet catalysts. The catalytic performance and H 2 O resistance of modified Mn-based catalysts by Fe, Ce, Co and Ni have shown a certain degree of improvement.…”

Section: Introductionmentioning

confidence: 99%

“…The catalytic performance and H 2 O resistance of modified Mn-based catalysts by Fe, Ce, Co and Ni have shown a certain degree of improvement. [24][25][26][27] Excellent H 2 O tolerance levels and high thermal stability have been obtained in novel MnFeO x nanorods and Mn 2 O 3 -doped Fe 2 O 3 hexagonal microsheet catalysts. [28,29] Meng et al reported that the addition of Sm on MnO x catalysts can markedly enhance the SCR activity and resistance to H 2 O.…”

Section: Introductionmentioning

confidence: 99%

Improved Low‐Temperature Activity and H₂O Resistance of Fe‐Doped Mn−Eu Catalysts for NO Removal by NH₃−SCR

et al. 2019

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Novel MnÀ EuÀ Fe catalysts were prepared via co-precipitation method for NO x removal by selective catalytic reduction with NH 3 (NH 3 À SCR). The MnÀ EuÀ Fe(1)-500 catalyst possessed the highest level of low-temperature activity, giving 98 % NO conversion at 100°C. This catalyst also exhibited excellent H 2 O resistance capacity, even at a high gas hourly space velocity (GHSV) of 75,000 h À 1 . The NO conversion still maintained at approximately 90 % in the presence of 15 % H 2 O at 230°C after 50 h, and the adverse effects of H 2 O could be quickly eliminated after the removal of H 2 O. Detailed characterization and analysis indicated that strong interactions among Mn, Eu and Fe resulted in the excellent low-temperature SCR activity and H 2 O resistance of the MnÀ EuÀ Fe(1)-500 catalyst. The strong interactions lead to larger specific surface area, higher concentrations of Mn 4 + , Fe 3 + and O α ; improved redox properties, increased acid sites and acid strength, and more adsorption amounts of NO/NH 3 in the presence of H 2 O. The MnÀ EuÀ Fe(1)-500 catalyst is a potential future catalyst for low-temperature NO x removal derived from high-H 2 O-content flue gases of natural gas combustion.

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Enhanced low-temperature NH 3 -SCR performance of MnO x /CeO 2 catalysts by optimal solvent effect

Cited by 100 publications

References 39 publications

Effect of Transition Metal Additives on the Catalytic Performance of Cu–Mn/SAPO-34 for Selective Catalytic Reduction of NO with NH3 at Low Temperature

Effect of Transition Metal Additives on the Catalytic Performance of Cu–Mn/SAPO-34 for Selective Catalytic Reduction of NO with NH3 at Low Temperature

Sulfur and Water Resistance of Mn-Based Catalysts for Low-Temperature Selective Catalytic Reduction of NOx: A Review

Improved Low‐Temperature Activity and H₂O Resistance of Fe‐Doped Mn−Eu Catalysts for NO Removal by NH₃−SCR

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Enhanced low-temperature NH 3 -SCR performance of MnO x /CeO 2 catalysts by optimal solvent effect

Cited by 100 publications

References 39 publications

Effect of Transition Metal Additives on the Catalytic Performance of Cu–Mn/SAPO-34 for Selective Catalytic Reduction of NO with NH3 at Low Temperature

Effect of Transition Metal Additives on the Catalytic Performance of Cu–Mn/SAPO-34 for Selective Catalytic Reduction of NO with NH3 at Low Temperature

Sulfur and Water Resistance of Mn-Based Catalysts for Low-Temperature Selective Catalytic Reduction of NOx: A Review

Improved Low‐Temperature Activity and H2O Resistance of Fe‐Doped Mn−Eu Catalysts for NO Removal by NH3−SCR

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Improved Low‐Temperature Activity and H₂O Resistance of Fe‐Doped Mn−Eu Catalysts for NO Removal by NH₃−SCR