The synergistic effects of cerium presence in the framework and the surface resistance to SO 2 and H 2 O in NH 3 -SCR

Fan, Yinming; Ling, Wei; Huang, Bichun; Dong, Lijie; Yu, Changming; Xi, Hongxia

doi:10.1016/j.jiec.2017.07.003

Cited by 55 publications

(9 citation statements)

References 43 publications

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“…Given that the dispersion of two active components on support enhances the active sites further, researchers have been widely reported the supported binary transition metal-based oxides to improve the performance and SO 2 /H 2 O tolerance in NH 3 -SCR reaction. With this perspective, several composites, such as MnCe/CNTs [118], Mn-Fe/TiO 2 [119], MnO x -CeO 2 /graphene [120], Mg-MnO x /TiO 2 [121], CeO x -MnO x /TiO 2 -graphene [122], Fe-Mn/Al 2 O 3 [123], Mn-Fe/W-Ti [124], MnO x -CeO 2 /TiO 2 -1%NG (NG = N-doped grapheme) [125], Mn-Ce/CeAPSO-34 [126], etc., were investigated for the NH 3 -SCR reaction at low-temperature. Smirniotis et al [22] studied the promotional effect of co-doped metals (Cr, Fe, Co, Ni, Cu, Zn, Ce, and Zr) on the NH 3 -SCR performance of Mn/TiO 2 .…”

Section: Supported Binary and Multi Transition Metal-based Catalystsmentioning

confidence: 99%

A Review of Low Temperature NH3-SCR for Removal of NOx

et al. 2019

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The importance of the low-temperature selective catalytic reduction (LT-SCR) of NOx by NH3 is increasing due to the recent severe pollution regulations being imposed around the world. Supported and mixed transition metal oxides have been widely investigated for LT-SCR technology. However, these catalytic materials have some drawbacks, especially in terms of catalyst poisoning by H2O or/and SO2. Hence, the development of catalysts for the LT-SCR process is still under active investigation throughout seeking better performance. Extensive research efforts have been made to develop new advanced materials for this technology. This article critically reviews the recent research progress on supported transition and mixed transition metal oxide catalysts for the LT-SCR reaction. The review covered the description of the influence of operating conditions and promoters on the LT-SCR performance. The reaction mechanism, reaction intermediates, and active sites are also discussed in detail using isotopic labelling and in situ FT-IR studies.

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Section: Supported Binary and Multi Transition Metal-based Catalystsmentioning

confidence: 99%

A Review of Low Temperature NH3-SCR for Removal of NOx

et al. 2019

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“…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.…”

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confidence: 99%

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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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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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“…Compared with manganese oxide, SO 2 preferentially combines with PrO x to form praseodymium sulfate and protecting the active sites of Mn. Fan et al [9] demonstrated that when the cerium oxides were incorporated in the framework and the surface of the Mn/SAPO-34 catalyst, the sulfate of the manganese oxide and the formation of NH 4 HSO 4 could be inhibited. In recent years, catalysts with hierarchical pore structures have attracted much attention for environmental catalytic applications.…”

Section: Introductionmentioning

confidence: 99%

Enhanced Catalytic Performance of Hierarchical MnOx/ZSM-5 Catalyst for the Low-Temperature NH3-SCR

Shao

Cheng

et al. 2020

Catalysts

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A ZSM-5 zeolite with a hierarchical pore structure was synthesized by the desilication-recrystallization method using tetraethyl ammonium hydroxide (TEAOH) and cetyltrimethylammonium bromide (CTAB) as the desilication and structure-directing agents, respectively. The MnO x /ZSM-5 catalyst was synthesized by the ethanol dispersion method and applied for the low-temperature selective catalytic reduction of NO x with NH 3 . The results showed that NO x conversion of the hierarchical MnO x /ZSM-5 catalyst could reach 100% at about 120 • C and could be maintained in the temperature range of 120-240 • C with N 2 selectivity over 90%. Furthermore, the hierarchical MnO x /ZSM-5catalyst presented better SO 2 resistance performance than the traditional catalyst in the presence of 100 ppm SO 2 at 120 • C. XRD, SEM, TEM, XPS, BET, NH 3 -TPD, and TG were applied to characterize the structural properties of the MnO x /ZSM-5 catalysts. These results showed that the MnO x /ZSM-5 catalyst had micropores (0.78 nm) and mesopores (3.2 nm) leading to a larger specific surface area, which improved the mass transfer of reactants and products while reducing the formation of sulfates. The better catalytic performance over hierarchical MnO x /ZSM-5 catalyst could be attributed to the higher concentration of Mn 4+ and chemisorbed oxygen species and higher surface acidity. The improved SO 2 resistance was related to the catalyst's hierarchical pore structure.

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The synergistic effects of cerium presence in the framework and the surface resistance to SO 2 and H 2 O in NH 3 -SCR

Cited by 55 publications

References 43 publications

A Review of Low Temperature NH3-SCR for Removal of NOx

A Review of Low Temperature NH3-SCR for Removal of NOx

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

Enhanced Catalytic Performance of Hierarchical MnOx/ZSM-5 Catalyst for the Low-Temperature NH3-SCR

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