In situ DRIFTS study of NO reduction by NH3 over Fe–Ce–Mn/ZSM-5 catalysts

Zhou, Guangying; Zhong, Biaocheng; Wang, Wenhui; Guan, Xiaojian; Huang, Bichun; Ye, Daiqi; Wu, Huijun

doi:10.1016/j.cattod.2011.06.004

Cited by 153 publications

(81 citation statements)

References 36 publications

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“…NH 3 -SCR catalyst with excellent catalytic activity at low temperatures (<200°C).Previous studies reported that Mn-Fe-Ce mixed metal-oxide catalysts possessed remarkable NH 3 -SCR activity [11][12][13]. However, the high-temperature treatment involved in their preparation was unsafe and expensive.…”

mentioning

confidence: 96%

One-step synthesis of ternary MnO2–Fe2O3–CeO2–Ce2O3/CNT catalysts for use in low-temperature NO reduction with NH3

Zhang

Zheng

Zou

et al. 2015

Catalysis Communications

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mentioning

confidence: 96%

One-step synthesis of ternary MnO2–Fe2O3–CeO2–Ce2O3/CNT catalysts for use in low-temperature NO reduction with NH3

Zhang

Zheng

Zou

et al. 2015

Catalysis Communications

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“…The mechanism of the SCR reaction had been studied extensively elsewhere and different hypotheses had been proposed (Li et al, 2011;Zhou et al, 2011;Fu et al, 2014;Yu et al, 2014). Fig.…”

Section: Discussionmentioning

confidence: 99%

“…It was noted that several adsorbed species were detected after injection of NH 3 for about 25 min. The weak bands corresponding to N-H stretching vibration modes of NH 3 , especially for the coordinated ammonia bonded to Lewis acid sites (3345, 3325, 3249 and 3152 cm -1 ) (Galvez et al, 2008;Sun et al, 2009;Jin et al, 2010;Liu et al, 2012) were observed at a broad band in the range of 3350-3100 cm -1 (Kijlstra et al, 1997a;Wu et al, 2007;Liu and He, 2010;Zhou et al, 2011). And the bands at 965 and 930 cm -1 attributed to gaseous state or weakly adsorbed NH 3 (Jiang et al, 2010;Jin et al, 2010;Liu et al, 2012) were also observed.…”

Section: Nh 3 Adsorption On Mno X /Mwcntsmentioning

confidence: 99%

“…With the supply of NO and O 2 mixture, the bands at 1741,1697,1648,1627,1559,1508, and 1457 cm -1 were clearly observed. These bands could be assigned to N 2 O 4 (a) (1741 and 1697 cm -1 ) (Zhou et al, 2011), bridging nitrate species (1648 and 1627 cm -1 ) (Kijlstra et al, 1997a;Zhao et al, 2009), bidentate nitrate (1559 cm -1 ) (Liu and He, 2010;Wu et al, 2010;Zhou et al, 2011;Zhang et al, 2013a), monodentate nitrate (1539 cm -1 ) (Zhang et al, 2013a), and nitrite species (1508 and 1457 cm -1 ) (Kijlstra et al, 1997a;Jin et al, 2010). When NO and O 2 were absorbed onto the surface of MnO x /MWCNTs catalysts for about 15 min, the intensity of bands at 2236 and 2221 cm -1 were detected and became larger afterwards.…”

Section: No and O 2 Co-adsorption On Mno X /Mwcntsmentioning

confidence: 99%

“…5. After all the reaction gases were supplied, the bands due to N 2 O (2241 and 2203 cm -1 ), nitrosyl NO− (1911 and 1847 cm -1 ) (Zhou et al, 2011), bridging nitrate (1627 cm -1 ) (Zhao et al, 2009) (Zhao et al, 2009) and the gaseous or weakly adsorbed NH 3 (966 and 928 cm -1 ) were detected. The bands due to bridging nitrate, coordinate ammonia species on Lewis acid sites, and the gaseous or weakly adsorbed NH 3 increased obviously with time.…”

Section: Scr Steady-state Response Experiments On Mno X /Mwcnts Catalmentioning

confidence: 99%

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In Situ DRIFTS Study of the Low Temperature Selective Catalytic Reduction of NO with NH3 over MnOx Supported on Multi-Walled Carbon Nanotubes Catalysts

Wang

Huang

2015

Aerosol Air Qual. Res.

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MnO x supported on multi-walled carbon nanotubes (MWCNTs) catalysts were prepared by the pore volume impregnation method and used for low-temperature selective catalytic reduction (SCR) of NO with NH 3 . Based on the previous study, 10 wt.% loading MnO x /MWCNTs were then selected for investigation of the reaction mechanism by in situ Diffuse Reflectance Infrared Fourier Transform spectroscopy (in-situ DRIFTS). The important intermediates in the SCR of NO x process at 210°C were discussed based on the DRIFTS results. Furthermore, the NH 3 -SCR reaction pathways over MnO x /MWCNTs catalysts were proposed. The results showed that NH 4 + species on Brønsted acid sites and coordinate ammonia species on Lewis acid sites existed during the SCR reaction. NH 4 + species was more active than coordinate ammonia species over the catalysts at 210°C. Most of NO x ad-species would react with NH 3 ad-species. However, nitrite species, bidentate and monodentate nitrates contributed to the SCR reaction over the catalysts mostly. Two possible reaction pathways were proposed. One was that NO x ad-species could react with NH 4 + to form intermediate of NH 4 N 2 O 4 (a), NH 4 NO 2 (a) or NH 4 NO 3 (a), then to produce N 2 and H 2 O as the final products. The other pathway was that NH 3 was initially adsorbed on active site and NH 2 was formed, then NH 2 reacted with NO x ad-species to produce intermediate NH 2 NO 2 or NH 2 NO 3 which were unstable and would decompose into N 2 and H 2 O.

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Nanoscale Precursor Distribution by Microfluidization for Scalable Production of Highly Efficient Thermocatalysts

Kim,

Lee,

Kim

et al. 2024

Adv Funct Materials

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The preparation of two‐dimensional (2D) materials often requires complicated exfoliation procedures having low yields. The exfoliated nanosheets are prone to thermal aggregation and unsuitable for thermocatalysis. Herein, a scalable approach produces 2D catalyst precursors well‐distributed and mixed at the nanoscale. Using continuous microfluidization and single‐layer layered double hydroxide (LDH) synthesis, the prepared suspension contained exfoliated hexagonal boron nitride (h‐BN) nanosheets and single‐layer LDHs. The increased contact area between h‐BN and LDHs enables the formation of highly dispersed MnCoAl mixed metal oxide nanoparticles anchored on h‐BN nanosheets after calcination. In the selective catalytic reduction of NOx with NH3 (NH3‐SCR, a representative thermocatalytic application), this nanocomposite demonstrates a record turnover frequency of 0.772 h−1 among reported Mn‐based NH3‐SCR catalysts, with high NOx conversion and high N2 selectivity at low temperatures. By creating 2D precursors mixed at the nanoscale, this new synthetic approach can realize the scalable production of highly efficient thermocatalysts.

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In situ DRIFTS study of NO reduction by NH3 over Fe–Ce–Mn/ZSM-5 catalysts

Cited by 153 publications

References 36 publications

One-step synthesis of ternary MnO2–Fe2O3–CeO2–Ce2O3/CNT catalysts for use in low-temperature NO reduction with NH3

One-step synthesis of ternary MnO2–Fe2O3–CeO2–Ce2O3/CNT catalysts for use in low-temperature NO reduction with NH3

In Situ DRIFTS Study of the Low Temperature Selective Catalytic Reduction of NO with NH3 over MnOx Supported on Multi-Walled Carbon Nanotubes Catalysts

Nanoscale Precursor Distribution by Microfluidization for Scalable Production of Highly Efficient Thermocatalysts

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