Selective catalytic reduction of NO with NH3 over manganese substituted iron titanate catalyst: Reaction mechanism and H2O/SO2 inhibition mechanism study

Liu, Fudong; He, Hong

doi:10.1016/j.cattod.2010.02.043

Cited by 198 publications

(102 citation statements)

References 40 publications

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“…It can be seen that, in the pure TiO2 sample, a broad signal was presented ranging from 500 °C to 650 °C, and the two reduction peaks located at 585 °C and 613 °C can be ascribed to the surface oxygen and lattice oxygen due to Ti 4+ to Ti 3+ [40]. When Fe was incorporated into the TiO2 support, a distinct overlapped peak shifted to the lower temperature range (400-565 °C).…”

Section: Structural Properties Of Catalystmentioning

confidence: 92%

Removal of NOX Using Hydrogen Peroxide Vapor over Fe/TiO2 Catalysts and an Absorption Technique

Chen

Zhao

et al. 2017

Catalysts

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Abstract:In this study, we proposed an innovative oxidation-absorption method for low-temperature denitrification (160-240 • C), in which NO is initially catalytically oxidized by hydrogen peroxide (H 2 O 2 ) vapor over titania-based catalysts, and the oxidation products are then absorbed by NaOH solution. The effects of flue gas temperature, molar H 2 O 2 /NO ratio, gas hourly space velocity (GHSV), and Fe substitution amounts of Fe/TiO 2 catalysts on the denitrification efficiency were investigated by a well-designed experiment. The results indicated that the Fe/TiO 2 catalyst exhibited a combination of remarkable activity and deep oxidation ability (NO converted into harmless NO 3 − ). In order to comprehend the functional mechanism of the Fe dopant's local environment in TiO 2 support, the promotional effect of the calcination temperature of Fe/TiO 2 on the denitration performance was also studied. A tentative synergetic mechanism could be interpreted from two aspects: (1) Fe 3+ as a substitute of Ti 4+ , leading to the formation of enriched oxygen vacancies at the surface, could significantly improve the adsorption efficiency of •OH; (2) the isolated surface Fe ion holds a strong adsorption affinity for NO, such that the adsorbed NO could be easily oxidized by the pre-formed •OH. This process offers a promising alternative for current denitrification technology.

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Section: Structural Properties Of Catalystmentioning

confidence: 92%

Removal of NOX Using Hydrogen Peroxide Vapor over Fe/TiO2 Catalysts and an Absorption Technique

Chen

Zhao

et al. 2017

Catalysts

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“…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%

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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“…Recently, a production line for catalytic converters was built by the China National Heavy Duty Truck Group Corp.; this line will be activated to meet the requirements of the China IV standards (implemented in 2012) for heavy-duty diesel vehicles (He et al, ZL02100669.5, ZL02157917.2, ZL 200710121422.4) ( Table 4). The RCEES successfully developed a series of high-/medium-/low-temperature NH 3 -SCR catalyst systems that effectively removed NOx from the flue gas of coal-fired power plants and industrial boilers in the presence of coexisting pollutants (Liu et al, , 2010aLiu and He, 2010;Shan et al, 2011aShan et al, , 2011b. The IUE also successfully developed a regeneration method for commercial deNOx catalysts and obtained good regeneration efficiencies (Shang et al, 2011(Shang et al, , 2012 (Table 4).…”

Section: Technique Development For the Removal Of Noxmentioning

confidence: 99%

Haze insights and mitigation in China: An overview

Zhuang

Wang

et al. 2014

Journal of Environmental Sciences

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Selective catalytic reduction of NO with NH3 over manganese substituted iron titanate catalyst: Reaction mechanism and H2O/SO2 inhibition mechanism study

Cited by 198 publications

References 40 publications

Removal of NOX Using Hydrogen Peroxide Vapor over Fe/TiO2 Catalysts and an Absorption Technique

Removal of NOX Using Hydrogen Peroxide Vapor over Fe/TiO2 Catalysts and an Absorption Technique

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

Haze insights and mitigation in China: An overview

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