Catalytic oxidation of NO over TiO2 supported platinum clusters. II: Mechanism study by in situ FTIR spectra

Li, Landong; Shen, Qun; Cheng, Jie; Hao, Zhengping

doi:10.1016/j.cattod.2010.04.038

Cited by 67 publications

(35 citation statements)

References 29 publications

(37 reference statements)

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“…The optimum NO oxidation efficiency reached at 200 • C. In contrast, the NO oxidation values for the molar H 2 O 2 /NO of 48 varied slightly with temperature and maintained a higher level than the others. NO 2 selectivity (Figure 1b) was positively associated with the temperature, and the growth of Catalysts 2017, 7, 386 3 of 17 NO 2 at a high-temperature segment could be due to the decomposition of formed nitrates [16]. As a consequence, the total amount of NO X removal (Figure 1c) (Figure 1d).…”

Section: Effects Of Molar H 2 O 2 /No and Temperaturementioning

confidence: 94%

“…Catalysts 2017, 7, 386 3 of 16 a high-temperature segment could be due to the decomposition of formed nitrates [16]. As a consequence, the total amount of NOX removal (Figure 1c) for the molar H2O2/NO range from 8 to 24 achieved a highest value at 200 °C, and showed a moderating trend along with the temperature for the molar H2O2/NO of 48.…”

Section: Effects Of Molar H 2 O 2 /No and Temperaturementioning

confidence: 96%

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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: Effects Of Molar H 2 O 2 /No and Temperaturementioning

confidence: 94%

Section: Effects Of Molar H 2 O 2 /No and Temperaturementioning

confidence: 96%

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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“…However, new support materials are also studied either in their pure form or in mixture with other metal-oxides [7]. In this regards TiO 2 has been intensively studied due to its better sulfur tolerance [8] and controlled surface dispersion of barium oxide (BaO) [9] as compared to γ-Al 2 O 3 .…”

Section: Introductionmentioning

confidence: 99%

NO 2 adsorption mechanism on TiO 2 : An in-situ transmission infrared spectroscopy study

Sivachandiran

Thévenet

Rousseau

et al. 2016

Applied Catalysis B: Environmental

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As soon as NO 2 molecules reach TiO 2 surface, they dimerized to N 2 O 4. • The adsorbed N 2 O 4 undergoes intra and intermolecular disproportionation reactions. NO 3 species. The intramolecular disproportionation reaction rate depends on NO 2 partial pressure, whereas the intermolecular disproportionation reaction rate depends on the coverage of NO 2 species and the number of available Ti 4+ sites. This mechanism is assessed for different NO 2 partial pressures ranging from 25 to 100 Pa. This study reveals that the configuration and the amount of the N-containing species on activated TiO 2 surface depend on the NO 2 concentration and the contact time.

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“…For Mn5 catalyst, nitrites were formed rapidly in the initial period. Subsequently, the intensity of nitrates increased whilst that of nitrites decreased, indicating that NO adsorbed on Mn5 to form nitrites and then formed NO2 and stable nitrates [48][49][50]. In other words, the storage of NO on Mn5 catalyst followed the "nitrite" pathway.…”

Section: In Situ Drifts Spectramentioning

confidence: 98%

High Performance of Mn-Doped MgAlOx Mixed Oxides for Low Temperature NOx Storage and Release

Cui

Li²,

Liu

et al. 2019

Catalysts

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NOx storage-reduction (NSR) is a potential approach for the effective removal of NOx under the lean conditions in lean-burn engines. Herein, manganese-doped mixed oxides (Mn/MgAlOx) with high performance for low temperature NOx storage and release were derived from hydrotalcites precursors prepared by a facile coprecipitation method. The catalysts were characterized by X-ray diffraction (XRD), SEM, N2 adsorption-desorption, H2-TPR, FT-IR, and X-ray photoelectron spectroscopy (XPS) techniques. The Mn-doped MgAlOx catalysts exhibited high NOx storage capacity (NSC) at low temperature range (150–300 °C), which was related to their increased surface area, improved reducibility and higher surface Mn3+ content. The largest NSC measured, 426 μmol/g, was observed for NOx adsorption at 200 °C on Mn15 catalyst (the sample containing 15 wt% of Mn). The in situ DRIFTS spectra of NOx adsorption proved that the Mn-doped hydrotalcite catalysts are preferred for low temperature NOx storage and release due to their ability to store NOx mainly in the form of thermally labile nitrites. NSR cycling tests revealed the NOx removal rate of Mn15 sample can reach above 70% within the wide temperature range of 150–250 °C. Besides, the influence of CO2, soot, H2O and SO2 on NOx storage performance of Mn15 catalyst was also studied. In all, owning to their excellent NOx storage capacity, NSR cycling performance, and resistance to CO2, soot, SO2 and H2O, the Mn-doped MgAlOx NSR catalysts have broad application prospects in NOx control at low temperatures.

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Catalytic oxidation of NO over TiO2 supported platinum clusters. II: Mechanism study by in situ FTIR spectra

Cited by 67 publications

References 29 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

NO 2 adsorption mechanism on TiO 2 : An in-situ transmission infrared spectroscopy study

High Performance of Mn-Doped MgAlOx Mixed Oxides for Low Temperature NOx Storage and Release

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