Dispersion and valence state of MnO2/Ce(1−x)ZrxO2–TiO2 for low temperature NH3-SCR

Jo, Seung-Hyeon; Shin, Byeongkil; Shin, Minchul; Tyne, C. J. Van; Lee, Heesoo

doi:10.1016/j.catcom.2014.08.014

Cited by 26 publications

(3 citation statements)

References 21 publications

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“…Metal (Fe, Cu)-exchanged zeolites [ZSM-5 (MFI topology), mordenite (MOR topology), and β (BEA topology)] have also been proposed. Unfortunately, the presence of hydrocarbons in exhaust gases induces their deactivations, as evidenced by Ma et al Among other metal oxides, performances of V 2 O 5 dispersed over TiO 2 , Al 2 O 3 , CeO 2 , and SiO 2 , as well as of ZrO 2 -supported active WO 3 , MoO x , MnO 2 , CeO 2 , and others, were evaluated. Smirniotis then pointed out the potential of manganese-based catalysts, with the highest performance being obtained for MnO x /TiO 2 (anatase phase) and an activity correlated to the redox properties of manganese oxide.…”

Section: Introductionmentioning

confidence: 99%

Morphology-Oriented ZrO₂-Supported Vanadium Oxide for the NH₃-SCR Process: Importance of Structural and Textural Properties

Liu

Wang

Wei

et al. 2019

ACS Appl. Mater. Interfaces

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ZrO 2 supports, with diverse morphologies (hollow sphere, star, rod, mesoporous), were produced using hydrothermal and evaporation-induced self-assembly methods. Zirconia-supported vanadium oxide catalysts were prepared by wet impregnation and used for the low-temperature selective catalytic reduction (SCR) of NO with ammonia. Characterization of catalysts includes N 2 physisorption, elementary analysis, X-ray diffraction, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, temperature-programmed reduction by H 2 , and temperature-programmed desorption of NH 3 . Significant differences in terms of activity are measured. 3 wt % V 2 O 5 supported on mesoporous ZrO 2 (V/MZ) presents excellent N 2 yields (>90%, in the 200−400 °C interval), with a wide operating temperature window (NO conversion > 95%, in the 225−425 °C interval), and less interesting performances were obtained when vanadium oxide is supported over stars, hollow spheres, and rods. Surface characterization showed a content of tetravalent vanadium ion, when supported, decreasing in the order of mesoporous > hollow sphere > star > rod. This order is in perfect agreement with the order of performance of the catalyst in the NH 3 -SCR reaction. The impact of tetravalent ion's presence on the surface is confirmed by diffuse reflectance infrared Fourier transform spectroscopy analysis, Brønsted acid sites generated on the surface, and the V 4+ -OH species involved in the reaction. The production of more important nitrite species over the tetragonal supported vanadium oxide catalyst could be another reason for the excellent NH 3 -SCR performance displayed by the V/MZ catalyst. When supported over monoclinic zirconia, like vanadium oxide over star-type morphology, the adsorbed NH 3 species (NH 4 + and coordinated NH 3 ) reacted with NO x adsorption species (nitrate) to form ammonium nitrate. Ammonium nitrate can be decomposed to N 2 and N 2 O (or NO 2 ). Thus, NO conversion curves and N 2 yield curves over tetragonal zirconia (MZ) at lower temperature were ahead of those over V/star ZrO 2 because of the higher V 4+ surface content and more active B acid sites associated with an easy formation of the nitrito intermediate.

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Section: Introductionmentioning

confidence: 99%

Morphology-Oriented ZrO₂-Supported Vanadium Oxide for the NH₃-SCR Process: Importance of Structural and Textural Properties

Liu

Wang

Wei

et al. 2019

ACS Appl. Mater. Interfaces

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“…In order to clearly observe the morphologies and the dispersion degrees of the active substance on the surface of catalysts, TEM and EDS tests are performed, as shown in Figure 4. It can clearly be seen that the three catalysts have the same microscopic morphology, which is basically characterized by the structural characteristics of titanium dioxide in Figure 4a-c [19].Figure 4d-f show the distribution of Mn on catalysts, and the difference in preparation method has a great influence on the distribution and content of Mn. MnO x had high dispersion in Figure 4f, which means a well-mixed state in all parts of the powder.…”

Section: Tem and Xrf Analysismentioning

confidence: 79%

Modification of V2O5-WO3/TiO2 Catalyst by Loading of MnOx for Enhanced Low-Temperature NH3-SCR Performance

Zhang

Diao

et al. 2020

Nanomaterials

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V2O5-WO3/TiO2 as a commercial selective catalytic reduction (SCR) catalyst usually used at middle-high temperatures was modified by loading of MnOx for the purpose of enhancing its performance at lower temperatures. Manganese oxides were loaded onto V-W/Ti monolith by the methods of impregnation (I), precipitation (P), and in-situ growth (S), respectively. SCR activity of each modified catalyst was investigated at temperatures in the range of 100–340 °C. Catalysts were characterized by specific surface area and pore size determination (BET), X-ray diffraction (XRD), temperature programmed reduction (TPR), etc. Results show that the loading of MnOx remarkably enhanced the SCR activity at a temperature lower than 280 °C. The catalyst prepared by the in-situ growth method was found to be most active for SCR.

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“…Transition metal (Fe, Cr, Ce, and Mn) oxide catalysts have been explored intensively in the low-temperature SCR reaction [7,8]. Mn-based oxide catalysts with the superiority of unique activities at low temperature and excellent redox properties have received much attention [9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Porous bimetallic Mn2Co1Ox catalysts prepared by a one-step combustion method for the low temperature selective catalytic reduction of NOx with NH3

Qiao

Wang

et al. 2015

Catalysis Communications

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Dispersion and valence state of MnO2/Ce(1−x)ZrxO2–TiO2 for low temperature NH3-SCR

Cited by 26 publications

References 21 publications

Morphology-Oriented ZrO₂-Supported Vanadium Oxide for the NH₃-SCR Process: Importance of Structural and Textural Properties

Morphology-Oriented ZrO₂-Supported Vanadium Oxide for the NH₃-SCR Process: Importance of Structural and Textural Properties

Modification of V2O5-WO3/TiO2 Catalyst by Loading of MnOx for Enhanced Low-Temperature NH3-SCR Performance

Porous bimetallic Mn2Co1Ox catalysts prepared by a one-step combustion method for the low temperature selective catalytic reduction of NOx with NH3

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Dispersion and valence state of MnO2/Ce(1−x)ZrxO2–TiO2 for low temperature NH3-SCR

Cited by 26 publications

References 21 publications

Morphology-Oriented ZrO2-Supported Vanadium Oxide for the NH3-SCR Process: Importance of Structural and Textural Properties

Morphology-Oriented ZrO2-Supported Vanadium Oxide for the NH3-SCR Process: Importance of Structural and Textural Properties

Modification of V2O5-WO3/TiO2 Catalyst by Loading of MnOx for Enhanced Low-Temperature NH3-SCR Performance

Porous bimetallic Mn2Co1Ox catalysts prepared by a one-step combustion method for the low temperature selective catalytic reduction of NOx with NH3

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Morphology-Oriented ZrO₂-Supported Vanadium Oxide for the NH₃-SCR Process: Importance of Structural and Textural Properties

Morphology-Oriented ZrO₂-Supported Vanadium Oxide for the NH₃-SCR Process: Importance of Structural and Textural Properties