Mechanism by which Tungsten Oxide Promotes the Activity of Supported V2O5/TiO2 Catalysts for NOX Abatement: Structural Effects Revealed by 51V MAS NMR Spectroscopy

Jaegers, Nicholas R.; Lai, Jun‐Kun; He, Yang; Walter, Éric; Dixon, David A.; Vasiliu, Monica; Chen, Ying; Wang, Chongmin; Hu, Mary Y.; Mueller, Karl T.; Wachs, Israel E.; Wang, Yong; Hu, Jian Zhi

doi:10.1002/anie.201904503

Cited by 104 publications

(48 citation statements)

References 64 publications

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“…Bulk tungsten oxide (WO 3 ) is composed of WO 6 units that are three-dimensionally connected 33 – 35 . Furthermore, WO 3 is known as a promoter for supported vanadia catalysts that enhance the reactivity of vanadia sites 36 . Therefore, the incorporation of tungsten sites into bulk V 2 O 5 would facilitate not only the NH 3 -SCR activity but also the structural stability of bulk vanadium oxide-based catalysts.…”

Section: Introductionmentioning

confidence: 99%

“…The reaction mechanisms of NH 3 -SCR have been widely investigated for a supported vanadium-based oxide catalyst under a dry gas condition using in situ and operando spectroscopic techniques (infrared (IR), ultraviolet–visible (UV–Vis), Raman) 20 , 36 , 38 , 46 , 50 – 54 . The current consensus is that both Lewis acid and Brønsted acid sites participate in the reaction mechanism.…”

Section: Introductionmentioning

confidence: 99%

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Bulk tungsten-substituted vanadium oxide for low-temperature NOx removal in the presence of water

et al. 2021

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NH3-SCR (selective catalytic reduction) is important process for removal of NOx. However, water vapor included in exhaust gases critically inhibits the reaction in a low temperature range. Here, we report bulk W-substituted vanadium oxide catalysts for NH3-SCR at a low temperature (100–150 °C) and in the presence of water (~20 vol%). The 3.5 mol% W-substituted vanadium oxide shows >99% (dry) and ~93% (wet, 5–20 vol% water) NO conversion at 150 °C (250 ppm NO, 250 ppm NH3, 4% O2, SV = 40000 mL h−1 gcat−1). Lewis acid sites of W-substituted vanadium oxide are converted to Brønsted acid sites under a wet condition while the distribution of Brønsted and Lewis acid sites does not change without tungsten. NH4+ species adsorbed on Brønsted acid sites react with NO accompanied by the reduction of V5+ sites at 150 °C. The high redox ability and reactivity of Brønsted acid sites are observed for bulk W-substituted vanadium oxide at a low temperature in the presence of water, and thus the catalytic cycle is less affected by water vapor.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Bulk tungsten-substituted vanadium oxide for low-temperature NOx removal in the presence of water

et al. 2021

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“…The worst “offenders” contributing to air pollution are NOx and CO emissions from vehicles/engines. Various technological advances have allowed to decrease the NO emissions from vehicles significantly relying on so‐called “three‐way‐catalysts (TWC)” and, more recently, selectively catalytic reduction technology (SCR) [1, 3–7, 9–11, 32] …”

Section: Introductionmentioning

confidence: 99%

Economizing on Precious Metals in Three‐Way Catalysts: Thermally Stable and Highly Active Single‐Atom Rhodium on Ceria for NO Abatement under Dry and Industrially Relevant Conditions**

et al. 2020

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We show for the first time that atomically dispersed Rh cations on ceria, prepared by ah igh-temperature atomtrapping synthesis,a re the active species for the (CO + NO) reaction. This provides ad irect link with the organometallic homogeneous Rh I complexes capable of catalyzing the dry (CO + NO) reaction. The thermally stable Rh cations in 0.1 wt %R h 1 /CeO 2 achieve full NO conversion with at urnover-frequency (TOF) of around 330 h À1 per Rh atom at 120 8 8C. Underdry conditions,the main product above100 8 8Cis N 2 with N 2 Ob eing the minor product. The presence of water promotes low-temperature activity of 0.1 wt %R h 1 /CeO 2 .I n the wet stream, ammonia and nitrogen are the main products above120 8 8C. The uniformity of Rh ions on the support, allows us to detect the intermediates of (CO + NO) reaction via IR measurements on Rh cations on zeolite and ceria. We also show that NH 3 formation correlates with the water gas shift (WGS) activity of the material and detect the formation of Rh hydride species spectroscopically.

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“…Selective catalytic reduction (SCR) technology is the most commonly used method to remove NO x from flue gas. 5 Research on a low-temperature SCR denitration catalyst started late in China. Although domestic research has made some progress, a certain distance from the industrial application remains.…”

Section: Introductionmentioning

confidence: 99%

Study on Denitration Performance of Solid Waste Blast Furnace Slag Catalysts under Different Preparation Processes

et al. 2020

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In this article, blast furnace slag, a high-yield industrial solid waste, was taken as the research object and it was used as the main material. Bentonite was used as the binder, and water was added to shape the blast furnace slag into a small column. The denitration catalyst was prepared using different methods, its denitration performances were compared and analyzed, and the best preparation method and process parameters were screened. Results showed that bentonite will clearly improve denitration performance, and 4:1 blast furnace slag and bentonite was selected as the molding ratio to reduce the effect of bentonite on its performance, combined with the hardness and surface adhesion of the prepared carrier. Separately, the catalysts were prepared using citric acid impregnation, hydrothermal decomposition, and mixing method, and active Mn was loaded. Among them, the hydrothermal decomposition method cannot completely decompose in a closed kettle, resulting in a lower denitration performance. The catalyst prepared using the mixing method is superior to that prepared using the impregnation method because the active component prepared by the former was more uniformly dispersed, and simple and easy to operate, which can meet the needs of the excess denitration catalysts of small enterprises.

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Mechanism by which Tungsten Oxide Promotes the Activity of Supported V₂O₅/TiO₂ Catalysts for NO_X Abatement: Structural Effects Revealed by ⁵¹V MAS NMR Spectroscopy

Cited by 104 publications

References 64 publications

Bulk tungsten-substituted vanadium oxide for low-temperature NOx removal in the presence of water

Bulk tungsten-substituted vanadium oxide for low-temperature NOx removal in the presence of water

Economizing on Precious Metals in Three‐Way Catalysts: Thermally Stable and Highly Active Single‐Atom Rhodium on Ceria for NO Abatement under Dry and Industrially Relevant Conditions**

Study on Denitration Performance of Solid Waste Blast Furnace Slag Catalysts under Different Preparation Processes

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