Selective catalytic reduction of NOx with NH3 over Mn-Ce mixed oxide catalyst at low temperatures

Liu, Z.; Yang, Yi; Zhang, Shaoxuan; Zhu, Tianle; Zhu, Junxing; Wang, Jinggang

doi:10.1016/j.cattod.2013.06.009

Cited by 255 publications

(128 citation statements)

References 28 publications

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“…Experimental analysis on NO adsorption on MnCeO x surface evidenced that the monodentate nitrate, bridging nitrate and bidentate nitrate could be observed after NO + O 2 adsorption (Guan et al, 2011;Liu et al, 2013). It is found that the activity of monodentate nitrate and bridging nitrates over the catalysts is much higher than that of bidentate nitrate (Guan et al, 2011).…”

Section: Introductionmentioning

confidence: 92%

NO Adsorption and Oxidation on Mn Doped CeO2 (111) Surfaces: A DFT+U Study

Liu¹,

Zheng²,

Wang³

et al. 2018

Aerosol Air Qual. Res.

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The adsorption of NO molecules on Mn-doped CeO 2 (111) surfaces for NO oxidation has been studied by employing the periodic density functional theory plus U (DFT+U) method. Through our calculations, it is demonstrated how Mn-doped CeO 2 with superior NO oxidation activity benefits from the high mobility of the oxygen near the Mn cations. On unreduced Mn-doped CeO 2 (111) surfaces, the NO molecule preferentially interacted with the first neighboring O of the Mn cation, with the N also bonding to an Mn cation (E ads = -3.30 eV) or Ce cation (E ads = -2.90 eV). When NO adsorbs on the surface of defective Mn-doped CeO 2 with O 2 adsorbed in advance, an ONOO* four atoms species is formed on the surface (E ads = -2.51 eV and -2.02 eV), which is an intermediate and can decompose into NO 2 , NO 2 * and O*. The adsorption structure with higher adsorption energy has a closer geometry to NO 2 , indicating a deeper oxidation of NO. The calculation results indicate that the presence of Mn only has a strong effect on the nearby oxygen atoms and that the Mndoped CeO 2 surface has similar properties to a noble metal in NO oxidation catalysis. In DOS plots, the spin of the electron state of the adsorption structures involving the oxidation of NO is symmetric, indicating that electron transfer occurs from the slab to NO and strong covalent bonds are formed between N and O on the slab, which can also be confirmed by the charge density difference plots.

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Section: Introductionmentioning

confidence: 92%

NO Adsorption and Oxidation on Mn Doped CeO2 (111) Surfaces: A DFT+U Study

Liu¹,

Zheng²,

Wang³

et al. 2018

Aerosol Air Qual. Res.

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“…Among the metal elements, cerium [24,25], chromium [10], iron [27,28,76], cobalt [29,30], copper [52], nickel [77], and several other elements have drawn the most attention as the mixture or dopant to construct binary metal oxide catalysts with MnOx. CeO2 has been studied extensively due to its good characteristics, such as increasing surface acidity after SO2 poisoning [78,79], high surface area [80,81], good dispersion of MnOx on the surface [45], and the redox shift between Ce 4+ …”

Section: 21mn-based Binary Metal Oxide Catalystsmentioning

confidence: 99%

“…CeO 2 has been studied extensively due to its good characteristics, such as increasing surface acidity after SO 2 poisoning [78,79], high surface area [80,81], good dispersion of MnO x on the surface [45], and the redox shift between Ce 4+ and Ce 3+ . It should be noted that the shift between Ce 4+ and Ce 3+ can result in the formation of oxygen vacancies and anincrease in the chemisorbed oxygen on the surface of Mn-Ce binary metal oxide catalysts, which are helpful for the enhancement of water and sulfur resistance [25,82]. Qi and Yang [24] reported that the Mn-Ce catalyst with a proper mole ratio (Mn/(Mn+Ce) = 0.3) showed great tolerance to water and sulfur.…”

Section: Mn-based Binary Metal Oxide Catalystsmentioning

confidence: 99%

“…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. 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].…”

Section: Mn-based Binary Metal Oxide Catalystsmentioning

confidence: 99%

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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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“…It has also been proven by Liu et al that with the increase the ratio of Ce/Mn, much more N 2 O will be generated. According to the definition of N 2 selectivity in Equation (2) mentioned below, the N 2 selectivity was decreased [16]. For practical application, the catalyst with reasonable molar ratios of Ce/Mn (0.3) can be chosen as a candidate for its high SCR activity, N 2 selectivity, and trace amount of N 2 O formation at low temperature.…”

Section: Scr Activity Of Different Molar Ratios Of Ce/mnmentioning

confidence: 99%

The CeOX and MnOX Nanocrystals Supported on TiO2–Graphene Oxide Catalysts and Their Selective Catalytic Reduction Properties at Low Temperature

Tong

Song

2017

Crystals

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Abstract:A series of 9%CeO x -MnO x /TiO 2 -GO nanocomposites with different molar ratios of Ce/Mn were synthesized by the sol-gel and ultrasonic impregnation methods and characterized by field emission scanning electron microscope (FESEM), high resolution transmission electron microscopy (HRTEM), N 2 adsorption (BET) analysis, X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FT-IR). The results showed that various valences of Ce and Mn oxides were uniformly distributed on the surface of TiO 2 -GO multilayered supports. The coexistence of various valences of Ce and Mn oxides can improve the redox performance of the catalyst. With the introduction of Ce, the amount of MnO 2 and non-stoichiometric MnO x /Mn, the total oxygen and chemisorbed oxygen content, and the electron transfer ability of the catalyst increased significantly. When the molar ratio of Ce/Mn was 0.3, the catalysts exhibited high selective catalytic reduction activity (more than 99% at 180 • C) and N 2 selectivity. The presence of hydrophilic groups on the surface of the GO was considered as the critical factor influencing the H 2 O resistance of the catalyst. Due to the pre-sulfuring process of GO, serious sulfation of the active component can be prevented, and the catalyst exhibited excellent SO 2 resistance.

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Selective catalytic reduction of NOx with NH3 over Mn-Ce mixed oxide catalyst at low temperatures

Cited by 255 publications

References 28 publications

NO Adsorption and Oxidation on Mn Doped CeO2 (111) Surfaces: A DFT+U Study

NO Adsorption and Oxidation on Mn Doped CeO2 (111) Surfaces: A DFT+U Study

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

The CeOX and MnOX Nanocrystals Supported on TiO2–Graphene Oxide Catalysts and Their Selective Catalytic Reduction Properties at Low Temperature

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