V2O5-WO3/TiO2 catalysts under thermal stress: Responses of structure and catalytic behavior in the selective catalytic reduction of NO by NH3

Kompio, Patrick G.W.A.; Brückner, Angelika; Hipler, Frank; Manoylova, Olga; Auer, Gerhard; Mestl, Gerhard; Grünert, Wolfgang

doi:10.1016/j.apcatb.2017.06.006

Cited by 56 publications

(35 citation statements)

References 61 publications

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“…6a). Furthermore, the widely used conventional, V 2 O 5 /TiO 2 39–41 and V 2 O 5 -WO 3 /TiO 2 38,42,48 , were synthesized for comparison. NO conversion of VT-1 (82%) was higher than that of V 2 O 5 /TiO 2 (30%) and V 2 O 5 -WO 3 /TiO 2 (28%) at 120 °C.…”

Section: Resultsmentioning

confidence: 99%

A zeolitic vanadotungstate family with structural diversity and ultrahigh porosity for catalysis

et al. 2018

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Design of the structure and composition of crystalline microporous inorganic oxides is of great importance in catalysis. Developing new zeolites is one approach towards this design because of the tunable pore system and high thermal stability. Zeolites are limited to main group elements, which limits their applications in redox catalysis. Another promising choice is zeolitic transition metal oxides providing both porosity and redox activity, thereby further expanding the diversity of porous materials. However, the examples of zeolitic transition metal oxides are rare. Here, we report a new class of zeolitic vanadotungstates with tunable frameworks exhibiting a large porosity and redox activity. The assembly of [W4O16]8− units with VO2+ forms two isomeric porous frameworks. Owing to the complex redox properties and open porosity, the vanadotungstates efficiently catalyse the selective reduction of NO by NH3. This finding provides an opportunity for design and synthesis of inorganic multifunctional materials for future catalytic applications.

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Section: Resultsmentioning

confidence: 99%

A zeolitic vanadotungstate family with structural diversity and ultrahigh porosity for catalysis

et al. 2018

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“…All the catalysts had bands near 394, 515, 636, and 790 cm −1 , that are due to the TiO 2 support (Figure 7c), and they all also produced peaks at 880 and 981 cm −1 (Figure 7a-d). Any of the catalysts indicated no band near 1020-1030 cm −1 regarding isolated surface VO x species [35,55]. The 981 and 880 cm −1 peaks had appeared even in the WT-only sample (Figure 7d).…”

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

confidence: 94%

“…These behaviors are consistent with those reported for 1. [35], and 1-5% V 2 O 5 on four different commercial WO 3 /TiO 2 supports with a WO 3 content of 4.7-6.8% [36]. After addition of 2.73% Fe 2 O 3 to VWT and c-VWT, these all gave a significant decrease in NO conversion above 400 • C. As an example, the 2.73% Fe 2 O 3 /VWT had a NO conversion of 60% at 480 • C, which is lower, by 20%, than that indicated over the unpromoted catalyst.…”

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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“…The thermal stability of catalysts is an important property to in-vestigate when assessing the commercial viability of a catalyst for NH3-SCR [21,22]. In commercial flue gas streams, large fluctuations in temperature are common and temperatures in excess of 600 °C can be observed under certain conditions [22].…”

Section: Introductionmentioning

confidence: 99%

SO2 promoted in situ recovery of thermally deactivated Fe2(SO4)3/TiO2 NH3-SCR catalysts: From experimental work to theoretical study

Chen

et al. 2019

Chemical Engineering Journal

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V2O5-WO3/TiO2 catalysts under thermal stress: Responses of structure and catalytic behavior in the selective catalytic reduction of NO by NH3

Cited by 56 publications

References 61 publications

A zeolitic vanadotungstate family with structural diversity and ultrahigh porosity for catalysis

A zeolitic vanadotungstate family with structural diversity and ultrahigh porosity for catalysis

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

SO2 promoted in situ recovery of thermally deactivated Fe2(SO4)3/TiO2 NH3-SCR catalysts: From experimental work to theoretical study

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