Understanding the co-effects of manganese and cobalt on the enhanced SCR performance for MnxCo1−xCr2O4 spinel-type catalysts

Gao, Erhao; Huang, Bei Qing; Zhao, Zilong; Pan, Hua; Zhang, Wei; Li, Younan; Bernards, Matthew T.; He, Yi; Shi, Yao

doi:10.1039/d0cy00872a

Cited by 28 publications

(17 citation statements)

References 47 publications

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“…According to several previous studies [58] combined with our findings, the L-H reaction pathway mainly occurs during the reaction as follows: (M denotes Fe and/or elemental Mn) 5a). The highly reactive NH 2 species reacted with NO x (NO, NO 2 ) to form NH 2 NO or NH 2 NO 2 , which rapidly discomposed into N 2 and H 2 O [57]. As given in Figure 5b, the adsorbed NO 2 or nitrates species reacts with adsorbed ammonia species when the NH 3 was confirmed to follow the Langmuir-Hishelwood (L-H) mechanism.…”

Section: Mechanisms and Reaction Pathwaysmentioning

confidence: 87%

“…With the introduction of NO + O2, most of the absorbed ammonia species decreased, and new species were formed (Figure 5a). The highly reactive NH2 species reacted with NOx (NO, NO2) to form NH2NO or NH2NO2, which rapidly discomposed into N2 and H2O [57]. As given in Figure 5b, the adsorbed NO2 or nitrates species reacts with adsorbed ammonia species when the NH3 was confirmed to follow the Langmuir-Hishelwood (L-H) mechanism.…”

Section: Mechanisms and Reaction Pathwaysmentioning

confidence: 89%

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A Study on Mn-Fe Catalysts Supported on Coal Fly Ash for Low-Temperature Selective Catalytic Reduction of NOX in Flue Gas

et al. 2020

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A series of Mn0.15Fe0.05/fly-ash catalysts have been synthesized by the co-precipitation method using coal fly ash (FA) as the catalyst carrier. The catalyst showed high catalytic activity for low-temperature selective catalytic reduction (LTSCR) of NO with NH3. The catalytic reaction experiments were carried out using a lab-scale fixed-bed reactor. De-NOx experimental results showed the use of optimum weight ratio of Mn/FA and Fe/FA, resulted in high NH3-SCR (selective catalytic reduction) activity with a broad operating temperature range (130–300 °C) under 50000 h−1. Various characterization methods were used to understand the role of the physicochemical structure of the synthesized catalysts on their De-NOx capability. The scanning electron microscopy, physical adsorption-desorption, and X-ray photoelectron spectroscopy showed the interaction among the MnOx, FeOx, and the substrate increased the surface area, the amount of high valence metal state (Mn4+, Mn3+, and Fe3+), and the surface adsorbed oxygen. Hence, redox cycles (Fe3+ + Mn2+ ↔ Mn3+ + Fe2+; Fe2+ + Mn4+ ↔ Mn3+ + Fe3+) were co-promoted over the catalyst. The balance between the adsorption ability of the reactants and the redox ability can promote the excellent NOx conversion ability of the catalyst at low temperatures. Furthermore, NH3/NO temperature-programmed desorption, NH3/NO- thermo gravimetric-mass spectrometry (NH3/NO-TG-MS), and in-situ DRIFTs (Diffuse Reflectance Infrared Fourier Transform Spectroscopy) results showed the Mn0.15Fe0.05/FA has relatively high adsorption capacity and activation capability of reactants (NO, O2, and NH3) at low temperatures. These results also showed that the Langmuir–Hinshelwood (L–H) reaction mechanism is the main reaction mechanism through which NH3-SCR reactions took place. This work is important for synthesizing an efficient and environmentally-friendly catalyst and demonstrates a promising waste-utilization strategy.

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Section: Mechanisms and Reaction Pathwaysmentioning

confidence: 87%

Section: Mechanisms and Reaction Pathwaysmentioning

confidence: 89%

A Study on Mn-Fe Catalysts Supported on Coal Fly Ash for Low-Temperature Selective Catalytic Reduction of NOX in Flue Gas

et al. 2020

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“…As shown in Fig. 5c, the Mn 2p3/2 spectra were deconvoluted into three peaks at 640.6, 641.7, and 643.0 eV, which were ascribed to the Mn 2+ , Mn 3+ , and Mn 4+ species, respectively (Gao et al 2020). The peak areas of the Mn 4+ species accounted for 43.8% and 48.1% before and after acetic acid ozonation.…”

Section: Characteristics Of the Mno2/γ-al2o3 Catalystsmentioning

confidence: 92%

Complete mineralization of acetic acid using catalytic ozonation with a high energy efficiency enhanced by MnO2/γ-Al2O3

Meng

Yao

Gao

et al. 2021

Preprint

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The complete mineralization of acetic acid in a biodegradation process is difficult due to the α-position methyl on the carboxyl group of acetic acid. This study explores the complete oxidation of acetic acid by catalytic ozonation. Metal oxides of MnO2, Co3O4, Fe3O4, and CeO2 loaded on γ-Al2O3 power were used as the catalysts. The experimental results showed that MnO2/γ-Al2O3 catalyst had the best mineralization performance for acetic acid. Typically, the mineralization of acetic acid is as high as 88.4% after 300 min ozonation of 100 mL of 1.0 g L‒1 acetic acid catalysed by 3.0 g 1.0wt.% MnO2/γ-Al2O3 catalyst powder with an energy efficiency of 15 g kWh‒1. However, without a catalyst, the mineralization of acetic acid is only 33.2% with an energy efficiency of 5.1 g kWh−1. The effects of MnO2 loading, catalyst dosage, acetic acid concentration, O3 concentration, ozonation temperature, and initial pH value of the acetic acid solution were systematically investigated. Radical quenchers and in-situ DRIFTS analyses indicated that •OH radical and reactive oxygen species on catalyst surface played an important role in the ozonation of acetic acid to CO2 and H2O. The mechanism of acetic acid oxidation on MnO2/γ-Al2O3 is proposed.

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“…10 Combined with XPS analysis, the changing of metal ion valence state would promote the generation of oxygen vacancy on the surface of catalytic, which was mainly responsible for NO adsorption and nitrate formation. 66 Thus, according to Fig. 7(a and b), the SCR reaction on CeCrLa/ TiO 2 -N could be facilitated through the following pathway (, denotes an oxygen vacancy):…”

Section: Investigation Of Reaction Mechanismmentioning

confidence: 99%

Improvement of low-temperature NH₃-SCR catalytic performance over nitrogen-doped MO_x–Cr₂O₃–La₂O₃/TiO₂–N (M = Cu, Fe, Ce) catalysts

Sun

Liu

et al. 2021

RSC Adv.

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Understanding the co-effects of manganese and cobalt on the enhanced SCR performance for Mn_xCo_1−xCr₂O₄ spinel-type catalysts

Abstract:
A novel ternary Mn_0.1Co_0.9Cr₂O₄ catalyst was identified from a range of chromium-based spinel-type oxides for the SCR of NOx in coking flue gas. The SCR reaction mainly occurs between the adsorbed NH₃ and the adsorbed nitrates, following the Langmuir–Hinshelwood mechanism.

Cited by 28 publications

References 47 publications

A Study on Mn-Fe Catalysts Supported on Coal Fly Ash for Low-Temperature Selective Catalytic Reduction of NOX in Flue Gas

A Study on Mn-Fe Catalysts Supported on Coal Fly Ash for Low-Temperature Selective Catalytic Reduction of NOX in Flue Gas

Complete mineralization of acetic acid using catalytic ozonation with a high energy efficiency enhanced by MnO2/γ-Al2O3

Improvement of low-temperature NH₃-SCR catalytic performance over nitrogen-doped MO_x–Cr₂O₃–La₂O₃/TiO₂–N (M = Cu, Fe, Ce) catalysts

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Understanding the co-effects of manganese and cobalt on the enhanced SCR performance for MnxCo1−xCr2O4 spinel-type catalysts

Abstract: A novel ternary Mn0.1Co0.9Cr2O4 catalyst was identified from a range of chromium-based spinel-type oxides for the SCR of NOx in coking flue gas. The SCR reaction mainly occurs between the adsorbed NH3 and the adsorbed nitrates, following the Langmuir–Hinshelwood mechanism.

Cited by 28 publications

References 47 publications

A Study on Mn-Fe Catalysts Supported on Coal Fly Ash for Low-Temperature Selective Catalytic Reduction of NOX in Flue Gas

A Study on Mn-Fe Catalysts Supported on Coal Fly Ash for Low-Temperature Selective Catalytic Reduction of NOX in Flue Gas

Complete mineralization of acetic acid using catalytic ozonation with a high energy efficiency enhanced by MnO2/γ-Al2O3

Improvement of low-temperature NH3-SCR catalytic performance over nitrogen-doped MOx–Cr2O3–La2O3/TiO2–N (M = Cu, Fe, Ce) catalysts

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Product

Resources

About

Understanding the co-effects of manganese and cobalt on the enhanced SCR performance for Mn_xCo_1−xCr₂O₄ spinel-type catalysts

Abstract:
A novel ternary Mn_0.1Co_0.9Cr₂O₄ catalyst was identified from a range of chromium-based spinel-type oxides for the SCR of NOx in coking flue gas. The SCR reaction mainly occurs between the adsorbed NH₃ and the adsorbed nitrates, following the Langmuir–Hinshelwood mechanism.

Improvement of low-temperature NH₃-SCR catalytic performance over nitrogen-doped MO_x–Cr₂O₃–La₂O₃/TiO₂–N (M = Cu, Fe, Ce) catalysts