Highly dispersed iron vanadate catalyst supported on TiO2 for the selective catalytic reduction of NOx with NH3

Liu, Fudong; He, Hong; Lian, Zhihua; Shan, Wenpo; Xie, Lijuan; Asakura, Kiyotaka; Yang, Weiwei; Deng, Hua

doi:10.1016/j.jcat.2013.08.003

Cited by 149 publications

(93 citation statements)

References 52 publications

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“…After thermal treatment at 750°C/10 h, a remarkable difference in the catalytic activity of the . This result confirms the stabilizing effect of iron in the form of hematite, as so far, NH 3 -SCR catalysts characterized by FeVO 4 as the active phase were reported to resist only moderate thermal treatments [19]. It is well known that the presence of WO 3 in the V 2 O 5 /TiO 2 SCR catalysts considerably contributes to both NO x reduction activity and thermal stability by inhibition of initial sintering of TiO 2 anatase and its subsequent transformation into rutile [23,24].…”

Section: Introductionsupporting

confidence: 86%

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Enhanced Stability of Fe2O3-Doped FeVO4/TiO2–WO3–SiO2 SCR Catalysts

et al. 2016

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This work investigates the effect of addition of Fe2O3 in FeVO4 supported on TiO2-WO3-SiO2 (TWS) NH3-SCR catalysts. The catalysts were prepared by loading 8.4 wt% FeVO4 and different amounts of Fe2O3 on TWS support and the effect of ageing in the range of temperature 650-750 degrees C on the SCR reaction was studied. Fe2O3 does not give any significant contribution to SCR activity for the samples treated at lower temperature, but a remarkable difference is achieved for the samples aged at 750 degrees C. The presence of Fe2O3 at an appropriate loading significantly enhances the thermal stability of the system by contrasting the formation of rutile and lowering the formation of surface VOx species

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Section: Introductionsupporting

confidence: 86%

“…The higher activity of FeVO 4 /TWS and Fe x Er 1 -x VO 4 /TWS compared to ErVO 4 /TWS were associated to the modification of their redox/acid-base properties. As reported in the work by Liu et al [19], the positive effect of Fe on SCR activity is due to the strong electronic interaction between Fe 3? and V 5?…”

Section: Introductionmentioning

confidence: 53%

Enhanced Stability of Fe2O3-Doped FeVO4/TiO2–WO3–SiO2 SCR Catalysts

et al. 2016

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“…All samples of V 2 O 5 /TiO 2 and V 2 O 5 -WO 3 /TiO 2 with low total surface coverage exhibited signals near 945 cm −1 in their Raman spectra collected at ambient conditions, and these were assigned to surface metavanadate species [55]. On the other hand, not only a significant electronic interaction between Fe 3+ species and V 5+ ones in titania-supported iron vanadates that are highly active for NH 3 -SCR reaction could be evident from the Fe and V K-edge X-ray absorption, but a reduced oxidation capability of the vanadium oxide in the V-O-Fe species was alsoproposed to give a better N 2 selectivity at high temperatures >300 • C [67]. Combining our Raman results with the earlier reports suggests that the tetrahedrally coordinated polymeric vanadates adjacent to Fe 2 O 3 species play a role in the reduction of N 2 O formed in NH 3 -SCR reaction at high temperatures by strongly-adsorbed NH 3 residues.…”

Section: Role Of Fe 2 O 3 Species For the Suppression Of N 2 O Formationmentioning

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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“…For this purpose, an active SCR catalyst formulation has been loaded over supports showing different soot oxidation functionalities. SCR catalyst materials were selected among metal/rare earth vanadates that have been shown to act as efficient catalyst precursors for NH 3 -SCR reaction [11][12][13][14][15][16], while among the different supports, standard TiO 2 -WO 3 -SiO 2 (TWS) was used and compared with more efficient carbon oxidation carriers like CeO 2 and Ce 0.75 Zr 0.25 O 2 [17]. In particular, this work investigates FeVO 4 and Fe 0.5 Er 0.5 VO 4 supported on TWS, CeO 2 , Ce 0.75 Zr 0.25 O 2 (CeZrO 2 ), and Al 2 O 3 in the simultaneous soot oxidation and NH 3 -SCR reactions.…”

Section: Introductionmentioning

confidence: 99%

Investigation of Iron Vanadates for Simultaneous Carbon Soot Abatement and NH3-SCR

2018

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FeVO 4 and Fe 0.5 Er 0.5 VO 4 were prepared and loaded over standard Selective Catalytic Reduction (SCR) supports based on TiO 2 -WO 3 -SiO 2 (TWS) and redox active supports like CeO 2 and CeZrO 2 with the aim of finding a suitable formulation for simultaneous soot abatement and NH 3 -SCR and to understand the level of interaction between the two reactions. A suitable bi-functional material was identified in the composition FeVO 4 /CeZrO 2 where an SCR active component is added over a redox active support, to increase carbon oxidation properties. The influence of the presence of ammonia in soot oxidation and the effect of the presence of soot on SCR reaction have been addressed. It is found that the addition of NO and NO/NH 3 mixtures decreases at different levels the oxidation temperature of carbon soot, while the presence of carbon adversely affects the NH 3 -SCR reaction by increasing the oxidation of NH 3 to NO, thus lowering the NO removal efficiency.

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Highly dispersed iron vanadate catalyst supported on TiO2 for the selective catalytic reduction of NOx with NH3

Cited by 149 publications

References 52 publications

Enhanced Stability of Fe2O3-Doped FeVO4/TiO2–WO3–SiO2 SCR Catalysts

Enhanced Stability of Fe2O3-Doped FeVO4/TiO2–WO3–SiO2 SCR Catalysts

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

Investigation of Iron Vanadates for Simultaneous Carbon Soot Abatement and NH3-SCR

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