Insights into the highly efficient Co modified MnSm/Ti catalyst for selective catalytic reduction of NO  with NH3 at low temperature

Liu, Lijun; Xiang, Jun; Xu, Kai; Li, Haifeng; Qing, Mengxia; Su, Sheng; Wang, Lele; Xiang, Jun

doi:10.1016/j.fuel.2019.115798

Cited by 40 publications

(10 citation statements)

References 49 publications

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“…In order to recover NH 3 -SCR activity, the 5CoCrCe catalyst was heated to 400 °C because ammonium bisulfate could be completely decomposed. 7 As expected, the 5CoCrCe catalyst could reach the initial NH 3 -SCR activity, suggesting its slight inactivation by 600 ppm SO 2 was reversible.…”

Section: Reaction Mechanism Over the 5cocrce Catalystsupporting

confidence: 72%

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Promotion effect of Co addition on the activity and SO₂ tolerance of CrCe catalysts for selective catalytic reduction of NO_x with NH₃ at middle–low temperatures

Zeng

Wei

et al. 2023

J of Chemical Tech & Biotech

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BackgroundNitrogen oxides (NOx) can result in a series of environmental issues (haze, photochemical smog and acid rain) that endanger human health. Currently, selective catalytic reduction (SCR) of NOx with ammonia (NH3‐SCR) has been considered to be one of the most efficient techniques to eliminate NOx.ResultsNovel Co‐modified chromium/cerium (CrCe) catalysts were synthesized by the citric acid method to improve their insufficient SCR activity and sulfur dioxide (SO2) resistance for NOx removal at middle–low temperatures. Cobalt (Co) addition could significantly increase the catalytic activity of CrCe catalysts, and the 5CoCrCe catalyst exhibited the highest catalytic activity with ≤95% NOx conversion and >80% N2 selectivity within 180–280 °C. In addition, the 5CoCrCe catalyst exhibited outstanding SO2 resistance as well as reversibility, with >90% NO conversion under 600 ppm SO2 for 510 min.ConclusionIt was determined by characterizations that Co addition can increase SSA, Cr6+ concentration, electron transfer between Co and Cr by redox cycle (Cr6+ + 4Co2+ ↔ 4Co3+ + Cr2+) and the redox properties of the CrCe catalyst. The 5CoCrCe catalyst surface consists mainly of Lewis acid and its NH3‐SCR reactions follows the Eley–Rideal (E–R) mechanism. The 5CoCrCe catalyst exhibited outstanding SO2 resistance due to higher Cr3+, Ce3+ and Oα concentrations and strong redox cycles (3Ce4+ + Cr3+ ↔ 3Ce3+ + Cr6+ and Cr6+ + 3Co2+ ↔ 3Co3+ + Cr3+). Furthermore, in situ DRIFTS results revealed that SO2 could induce more adsorbed NOx and NH3 species instead of bulk sulfate, which also was responsible for good SO2 resistance. © 2023 Society of Chemical Industry.

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Section: Reaction Mechanism Over the 5cocrce Catalystsupporting

confidence: 72%

“…6 In addition, the SCR unit must be placed upstream of a dust separator and flue gas desulfurization device, and the temperature of exhaust gases at the SCR unit obviously drops (<300 °C). 7 Thus, it is necessary to develop environmentally friendly and high-efficiency SCR catalysts at middle-low temperatures.…”

Section: Introductionmentioning

confidence: 99%

Promotion effect of Co addition on the activity and SO₂ tolerance of CrCe catalysts for selective catalytic reduction of NO_x with NH₃ at middle–low temperatures

Zeng

Wei

et al. 2023

J of Chemical Tech & Biotech

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“…, the NH 4 + adsorbed on Brønsted acid sites (1405 cm −1 ), and -NH 2 (1540 cm −1 )[48,50]. From the different intensities of the Lewis and Brønsted acid species, it was found that Lewis acid sites were dominant in the MCTO-600, in accordance with the NH 3 -TPD results.…”

supporting

confidence: 77%

“…During the experiment, NH3 was firstly pre-adsorbed at 200 °C for 30 min, then purged with He for 30 min, and finally NO + O2 was passed in for different times to obtain the results, as shown in Figure 8a. After the introduction of NH3, some NH3 species appeared on the surface of the MCTO-600 catalyst, including the coordinated NH3 on the Lewis acid sites (1172, 1594, 3267, 3391 cm −1 ) [48,49], the NH4 + adsorbed on Brønsted acid sites (1405 cm −1 ), and -NH2 (1540 cm −1 ) [48,50]. From the different intensities of the Lewis and Brønsted acid species, it was found that Lewis acid sites were dominant in the MCTO-600, in accordance with the NH3-TPD results.…”

Section: Catalystmentioning

confidence: 99%

Preparation of Mesoporous Mn–Ce–Ti–O Aerogels by a One-Pot Sol–Gel Method for Selective Catalytic Reduction of NO with NH3

et al. 2020

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Novel Mn–Ce–Ti–O composite aerogels with large mesopore size were prepared via a one-pot sol–gel method by using propylene oxide as a network gel inducer and ethyl acetoacetate as a complexing agent. The effect of calcination temperature (400, 500, 600, and 700 °C) on the NH3–selective catalytic reduction (SCR) performance of the obtained Mn–Ce–Ti–O composite aerogels was investigated. The results show that the Mn–Ce–Ti–O catalyst calcined at 600 °C exhibits the highest NH3–SCR activity and lowest apparent activation energy due to its most abundant Lewis acid sites and best reducibility. The NO conversion of the MCTO-600 catalyst maintains 100% at 200 °C in the presence of 100 ppm SO2, showing the superior resistance to SO2 poisoning as compared with the MnOx–CeO2–TiO2 catalysts reported the literature. This should be mainly attributed to its large mesopore sizes with an average pore size of 32 nm and abundant Lewis acid sites. The former fact facilitates the decomposition of NH4HSO4, and the latter fact reduces vapor pressure of NH3. The NH3–SCR process on the MCTO-600 catalyst follows both the Eley–Rideal (E–R) mechanism and the Langmuir–Hinshelwood (L–H) mechanism.

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“…It is generally accepted that O α is more active than O β as a result of its relatively higher mobility and lower energy bonding to the surface, hence, O α plays a more important role in the oxidation process. [ 28,29 ] The Mn 2p 3/2 XPS spectra of 20Mn‐TiO 2 is displayed in Figure 4D. The characteristic peaks at 642.1 and 640.7 eV are ascribed to the existence of Mn 3+ and Mn 2+ , respectively.…”

Section: Resultsmentioning

confidence: 99%

Selective liquid‐phase oxidation of toluene with molecular oxygen catalyzed by Mn‐TiO₂ under solvent‐free conditions

et al. 2022

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In this paper, we reported the preparation, characterization, and catalytic performance of TiO 2 doped with Mn for the selective oxidation of toluene to benzyl alcohol and benzaldehyde without any solvent. The structure of the catalyst was determined by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), nitrogen adsorption-desorption analysis (Brunauer-Emmet-Teller [BET]), scanning electron microscope (SEM), transmission electron microscope (TEM), and mapping. The results demonstrated that the catalytic properties of Mn-TiO 2 were higher than those of pure Mn 3 O 4 and TiO 2 . The effects of reaction temperature, reaction time, oxygen pressure, and the amount of catalyst were studied. Under the optimal conditions, Mn-TiO 2 could afford 6.4% toluene conversion at a combined benzyl alcohol/benzaldehyde selectivity of 58.6%. Moreover, the catalyst can be repeated in the experiment for five times without significant loss of activity.

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Insights into the highly efficient Co modified MnSm/Ti catalyst for selective catalytic reduction of NO with NH3 at low temperature

Cited by 40 publications

References 49 publications

Promotion effect of Co addition on the activity and SO₂ tolerance of CrCe catalysts for selective catalytic reduction of NO_x with NH₃ at middle–low temperatures

Promotion effect of Co addition on the activity and SO₂ tolerance of CrCe catalysts for selective catalytic reduction of NO_x with NH₃ at middle–low temperatures

Preparation of Mesoporous Mn–Ce–Ti–O Aerogels by a One-Pot Sol–Gel Method for Selective Catalytic Reduction of NO with NH3

Selective liquid‐phase oxidation of toluene with molecular oxygen catalyzed by Mn‐TiO₂ under solvent‐free conditions

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Insights into the highly efficient Co modified MnSm/Ti catalyst for selective catalytic reduction of NO with NH3 at low temperature

Cited by 40 publications

References 49 publications

Promotion effect of Co addition on the activity and SO2 tolerance of CrCe catalysts for selective catalytic reduction of NOx with NH3 at middle–low temperatures

Promotion effect of Co addition on the activity and SO2 tolerance of CrCe catalysts for selective catalytic reduction of NOx with NH3 at middle–low temperatures

Preparation of Mesoporous Mn–Ce–Ti–O Aerogels by a One-Pot Sol–Gel Method for Selective Catalytic Reduction of NO with NH3

Selective liquid‐phase oxidation of toluene with molecular oxygen catalyzed by Mn‐TiO2 under solvent‐free conditions

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About

Promotion effect of Co addition on the activity and SO₂ tolerance of CrCe catalysts for selective catalytic reduction of NO_x with NH₃ at middle–low temperatures

Promotion effect of Co addition on the activity and SO₂ tolerance of CrCe catalysts for selective catalytic reduction of NO_x with NH₃ at middle–low temperatures

Selective liquid‐phase oxidation of toluene with molecular oxygen catalyzed by Mn‐TiO₂ under solvent‐free conditions