A new view on the relations between tungsten and vanadium in V2O5WO3/TiO2 catalysts for the selective reduction of NO with NH3

Kompio, Patrick G.W.A.; Brückner, Angelika; Hipler, Frank; Auer, Gerhard; Löffler, Elke; Grünert, Wolfgang

doi:10.1016/j.jcat.2011.11.008

Cited by 262 publications

(188 citation statements)

References 47 publications

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“…% V2O5/WT), Amiridis et al [31] (1.0, 2.0, 3.5, 3.9, 6.6, 8.5, 11.1, and 15.9 wt. % V2O5/WT), Kompio et al [7] (0.5, 1.5, 3.0, 5.0 wt. % V2O5/WT) and Djerad et al [3] (3 and 8 wt.…”

Section: Introductionmentioning

confidence: 96%

“…% V2O5 as the active redox species [3][4][5]. Despite the conventional V2O5 notation, vanadium is actually dispersed as VOx species over the high surface area support [6][7][8]. WO3 is proposed to have multiple promoting effects including the prevention of V island formation [7], increase the number of NH3 adsorption sites [9] or improvement of thermal stability of the thermodynamically unfavorable anatase phase [4].…”

Section: Introductionmentioning

confidence: 99%

“…The V loading has been investigated on various support materials such as Al2O3, ZrO2, SiO2 or TiO2 [3,7,[26][27][28]. Among these, WT has often been used for V-based SCR catalyst preparation.…”

Section: Introductionmentioning

confidence: 99%

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VOx Surface Coverage Optimization of V2O5/WO3-TiO2 SCR Catalysts by Variation of the V Loading and by Aging

et al. 2015

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V2O5/WO3-TiO2 selective catalytic reduction (SCR) catalysts with a V2O5 loading of 1.7, 2.0, 2.3, 2.6, 2.9, 3.2 and 3.5 wt. % were investigated in the fresh state and after hydrothermal aging at 600 °C for 16 h. The catalysts were characterized by means of nitrogen physisorption, X-ray diffraction and X-ray absorption spectroscopy. In the fresh state, the SCR activity increased with increasing V loading. Upon aging, the catalysts with up to 2.3 wt. % V2O5 exhibited higher NOx reduction activity than in the fresh state, while the catalysts with more than 2.6 wt. % V2O5 showed increasing deactivation tendencies. The observed activation and deactivation were correlated with the change of the VOx and WOx surface coverages. Only catalysts with a VOx coverage below 50% in the aged state did not show deactivation tendencies. With respect to tungsten, above one monolayer of WOx, WO3 particles were formed leading to loss of surface acidity, sintering, catalyst deactivation and early NH3 slip. An optimal compromise between activity and hydrothermal aging resistance could be obtained only with V2O5 between 2.0 and 2.6 wt. %.

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“…% V2O5/WT), Amiridis et al [31] (1.0, 2.0, 3.5, 3.9, 6.6, 8.5, 11.1, and 15.9 wt. % V2O5/WT), Kompio et al [7] (0.5, 1.5, 3.0, 5.0 wt. % V2O5/WT) and Djerad et al [3] (3 and 8 wt.…”

Section: Introductionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

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VOx Surface Coverage Optimization of V2O5/WO3-TiO2 SCR Catalysts by Variation of the V Loading and by Aging

et al. 2015

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“…They are usually formulated to 0.1-3% V 2 O 5 and 7-10% WO 3 or 6-10% MoO 3 [3][4][5][6][7][8], depending on industrial application target, and V 2 O 5 -WO 3 /TiO 2 systems are prevailed for such deNO x processes. The overall NH 3 -SCR reaction with V 2 O 5 /TiO 2 -based catalysts could be adequately described by [5][6][7]:…”

Section: Introductionmentioning

confidence: 99%

The Role of Fe2O3 Species in Depressing the Formation of N2O in the Selective Reduction of NO by NH3 over V2O5/TiO2-Based Catalysts

Kim

Yang

2018

Catalysts

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Promotion of 2.73% Fe 2 O 3 in an in-house-made V 2 O 5 -WO 3 /TiO 2 (VWT) and a commercial V 2 O 5 -WO 3 /TiO 2 (c-VWT) has been investigated as a cost effective approach to the suppression of N 2 O formation in the selective catalytic reduction of NO by NH 3 (NH 3 -SCR). The promoted VWT and c-VWT catalysts all gave a significantly decreased N 2 O production at temperatures >400 • C compared to the unpromoted samples. However, such a promotion led to the loss in high temperature NO conversion, mainly due to the oxidation of NH 3 to N-containing gases, particularly NO. Characterization of the unpromoted and promoted catalysts using X-ray diffraction (XRD), NH 3 adsorption-desorption, and Raman spectroscopy techniques could explain the reason why the promotion showed much lower N 2 O formation levels at high temperatures. The addition of Fe 2 O 3 to c-VWT resulted in redispersion of the V 2 O 5 species, although this was not visible for 2.73% Fe 2 O 3 /VWT. The iron oxides exist as a highly-dispersed noncrystalline α-Fe 2 O 3 in the promoted catalysts. These Raman spectra had a new Raman signal that could be tentatively assigned to Fe 2 O 3 -induced tetrahedrally coordinated polymeric vanadates and/or surface V-O-Fe species with significant electronic interactions between the both metal oxides. Calculations of the monolayer coverage of each metal oxide and the surface total coverage are reasonably consistent with Raman measurements. The proposed vanadia-based surface polymeric entities may play a key role for the substantial reduction of N 2 O formed at high temperatures by NH 3 species adsorbed strongly on the promoted catalysts. This reaction is a main pathway to greatly suppress the extent of N 2 O formation in NH 3 -SCR reaction over the promoted catalysts.

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“…Nitrogen oxides (NOx), as major atmospheric pollutants (Yu et al, 2013;Liu et al, 2014), have caused a series of environmental issues, such as ozone depletion, acid rain, photochemical smog, particulate matters (PM2.5) transformation, greenhouse effect etc (Skalska et al, 2010;Kompio et al, 2012;Yang et al, 2014;Huang et al, 2015;Ma et al, 2015). In recent years, with the significant growth of environmental awareness, the environmental problems arising from nitrogen oxides (NOx) have been paid more attention.…”

Section: Introductionmentioning

confidence: 99%

Effects of V2O5 and WO3 loadings on the catalytic performance of V2O5-WO3/TiO2 catalyst for SCR of NO with NH3

2017

Global NEST Journal

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V2O5-WO3/TiO2 catalysts were fabricated by a simple impregnation method. Effects of V2O5 and WO3 loadings on the catalytic performance of V2O5-WO3/TiO2 catalyst for selective catalytic reduction (SCR) of NO with NH3 were investigated. Morphology and structure of the V2O5-WO3/TiO2 catalysts were characterised by XRD, SEM, XPS, and N2 adsorption techniques. The XRD patterns of the V2O5-WO3/TiO2 catalyst are indexed to anatase-TiO2. XPS spectra analysis confirms that V, Ti, W and O species exist on the surface of V2O5-WO3/TiO2 catalyst. V2O5 species are the main active sites in the process of SCR reaction. Increasing V2O5 loading in the V2O5-WO3/TiO2 catalysts can improve their catalytic performance. Exceeding 2 wt%, the catalytic performance of V2O5-WO3/TiO2 catalyst begins to decline because high V2O5 loading on TiO2 speeds up the growth of anatase grains, which leads to the loss of catalytic activity. Appropriate WO3 species can significantly improve the catalytic performance of V2O5-WO3/TiO2 catalysts. However, as the WO3 loadings reaches 6 wt%, NO conversion decreases instead.

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A new view on the relations between tungsten and vanadium in V2O5WO3/TiO2 catalysts for the selective reduction of NO with NH3

Cited by 262 publications

References 47 publications

VOx Surface Coverage Optimization of V2O5/WO3-TiO2 SCR Catalysts by Variation of the V Loading and by Aging

VOx Surface Coverage Optimization of V2O5/WO3-TiO2 SCR Catalysts by Variation of the V Loading and by Aging

The Role of Fe2O3 Species in Depressing the Formation of N2O in the Selective Reduction of NO by NH3 over V2O5/TiO2-Based Catalysts

Effects of V2O5 and WO3 loadings on the catalytic performance of V2O5-WO3/TiO2 catalyst for SCR of NO with NH3

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