Selective catalytic reduction of NO with NH3 at low temperatures over iron and manganese oxides supported on mesoporous silica

Huang, Jihui; Tong, Zhiquan; Huang, Yan; Zhang, Junfeng

doi:10.1016/j.apcatb.2007.09.031

Cited by 173 publications

(98 citation statements)

References 22 publications

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“…As shown in Figure 8, the spectrum of all fresh catalysts exhibited three characteristic peaks at 3440 cm −1 , corresponding to the vibration of -OH units [39][40][41]; at 1645 cm −1 , which was ascribed to the stretching vibration of C=C on the surface of MWCNTs [42]; and a broad peak in the 1000-400 cm −1 range, which was attributed to the stretching vibration of metallic oxide groups (Me-O-Me) [43,44]. Compared to the fresh catalysts, a peak around 1102 cm −1 , assigned to the SO 4 2− species, appeared after reacting with SO 2 [6,45]. From the partial magnification of corresponding FTIR spectra, the peak became weaker after loading Ce or Y, indicating that the addition of Ce or Y may prevent the manganese active sites from being sulfated to some extent [46].…”

Section: Ftir Analysismentioning

confidence: 99%

“…Therefore, there is great interests in developing new catalysts which are active at relatively low temperatures and have better resistance to SO 2 and H 2 O. Some transition metal oxides (Fe, V, Cr, Cu, Mn) supported on catalysts have been found with high activities at low temperatures [5][6][7][8][9]. Among them, Mn-based catalysts have been investigated in depth via several means because manganese oxides contain various kinds of labile oxygen, which is beneficial for the fulfillment of the catalytic cycle [9][10][11][12][13][14][15][16].…”

Section: Introductionmentioning

confidence: 99%

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Effect of Ce/Y Addition on Low-Temperature SCR Activity and SO2 and H2O Resistance of MnOx/ZrO2/MWCNTs Catalysts

et al. 2017

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Abstract:The effects of SO 2 and H 2 O on the low-temperature selective catalytic reduction (SCR) activity over MnO x /ZrO 2 /MWCNTs and MnO x /ZrO 2 /MWCNTs catalysts modified by Ce or Y was studied. MnCeZr and MnYZr catalysts reached nearly 100% and 93.9% NO x conversions at 200 • C and 240 • C, respectively. They displayed a better SO 2 tolerance, and the effect of H 2 O was negligible. The structural properties of the catalysts were characterized by XRD, H 2 -TPR, XPS, and FTIR before and after the reaction. The results showed that Ce could increase the mobility of the oxygen and improve the valence and the oxidizability of manganese, while the effect of Y was the opposite. This might be the main reason why the catalytic activity of MnCeZr was better than MnYZr in the presence or absence of SO 2 and H 2 O. Doping Ce or Y broadened the active temperature window. Ce or Y, which existed in the catalysts with a high dispersion or at the amorphous state, preferred to react with SO 2 to form sulfate species, and protected the manganese active sites from combing with SO 2 to some extent, which coincided with the theory of ionic polarization.

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Section: Ftir Analysismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effect of Ce/Y Addition on Low-Temperature SCR Activity and SO2 and H2O Resistance of MnOx/ZrO2/MWCNTs Catalysts

et al. 2017

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“…(Figure 30) [52]. Huang et al prepared a mesoporous silica-supported Mn-Fe catalyst and found that its SCR activity was suppressed gradually in the presence of SO 2 and H 2 O, and the inhibitory effect was relieved after heating treatment [88]. …”

Section: Carbon Materials Supported Mn-based 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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“…However, their operating temperature (300-400 • C) limits the location of the SCR reactor to upstream from the electrostatic precipitator and desulfurizer [7,8]. This limitation causes some problems, such as the tendency to catalyse the rapid oxidation of SO 2 to SO 3 , the corrosion of the downstream devices, and high concentrations of particulates and SO 2 in the flue gases, which shorten the life of the catalyst [9]. Toavoid these adverse effects, it has been suggested that the SCR reactor could be located downstream of the particle control and desulfurizer devices where the flue gas temperature is typically below 150 • C. In particular, after the wet desulfurization process, the flue gas will be cool, even below 100 • C [10,11].…”

Section: Introductionmentioning

confidence: 99%

Poisoning Effect of SO2 on Honeycomb Cordierite-Based Mn–Ce/Al2O3Catalysts for NO Reduction with NH3 at Low Temperature

et al. 2018

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Honeycomb cordierite-based Mn-Ce/Al 2 O 3 catalysts were prepared by the impregnation method and used for low-temperature selective catalytic reduction (SCR) of NO x with NH 3 , with and without SO 2 and/or H 2 O in a homemade fixed-bed tubular reactor. The catalyst reached nearly 80% NO x conversion at 100 • C in the absence of SO 2 . However, SO 2 reduces the catalytic activity (80% to 72%) of the honeycomb cordierite-based Mn-Ce/Al 2 O 3 catalysts under identical conditions. This finding demonstrated that the catalyst exhibited high activity at low temperature and excellent SO 2 resistance in the presence of 50 ppm SO 2 . The fresh and sulfated honeycomb cordierite-based Mn-Ce/Al 2 O 3 catalysts were characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), N 2 adsorption-desorption, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), thermogravimetry and differential thermal analysis (TG-DTA), and Fourier transform infrared (FT-IR) spectroscopy. Characterization results indicated that the deactivation by SO 2 was primarily the result of the deposition of ammonium hydrogen sulfate and sulfated CeO 2 on the catalyst surface during the SCR process. The formed sulfates depressed the catalytic activity via the blocking of pores and the occupation of active sites. Additionally, the competitive adsorption between SO 2 and NH 3 always decreased the catalytic activity.

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Selective catalytic reduction of NO with NH3 at low temperatures over iron and manganese oxides supported on mesoporous silica

Cited by 173 publications

References 22 publications

Effect of Ce/Y Addition on Low-Temperature SCR Activity and SO2 and H2O Resistance of MnOx/ZrO2/MWCNTs Catalysts

Effect of Ce/Y Addition on Low-Temperature SCR Activity and SO2 and H2O Resistance of MnOx/ZrO2/MWCNTs Catalysts

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

Poisoning Effect of SO2 on Honeycomb Cordierite-Based Mn–Ce/Al2O3Catalysts for NO Reduction with NH3 at Low Temperature

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