Selective catalytic reduction of NO by NH3 over Fe2O3-promoted V2O5/TiO2-based catalysts with high Fe2O3-to-V2O5 ratios

Nguyen, Thi Phuong Thao; Yang, Ki Hyuck; Kim, Moon Hyeon; Hong, Yong Seok

doi:10.1016/j.cattod.2020.02.021

Cited by 10 publications

(20 citation statements)

References 52 publications

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“…To identify the types of acid sites, DRIFT studies of NH 3 adsorption at 150 • C were performed and shown in Figure 4. The bands at 1672 cm −1 and 1430 cm −1 were attributed to NH 4 + species adsorbed on Brønsted acid sites, and bands at 1606 cm −1 and 1209 cm −1 were ascribed to NH 3 species adsorbed on Lewis acid sites [46][47][48]. By comparing the intensity of bands at 1430 cm −1 , one can easily observe that more NH 4 + species adsorbed on Brønsted acid sites on FeM 0.3 O x -C catalysts than on FeM 0.3 O x catalysts.…”

Section: Acidity and Redox Ability 241 Acidic Propertiesmentioning

confidence: 99%

Iron-Based Composite Oxide Catalysts Tuned by CTAB Exhibit Superior NH3–SCR Performance

et al. 2021

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Iron-based oxide catalysts for the NH3–SCR (selective catalytic reduction of NOx by NH3) reaction have gained attention due to their high catalytic activity and structural adjustability. In this work, iron–niobium, iron–titanate and iron–molybdenum composite oxides were synthesized by a co-precipitation method with or without the assistance of hexadecyl trimethyl ammonium bromide (CTAB). The catalysts synthesized with the assistance of CTAB (FeM0.3Ox-C, M = Nb, Ti, Mo) showed superior SCR performance in an operating temperature range from 150 °C to 400 °C compared to those without CTAB addition (FeM0.3Ox, M = Nb, Ti, Mo). To reveal such enhancement, the catalysts were characterized by N2-physisorption, XRD (Powder X-ray diffraction), NH3-TPD (temperature-programmed desorption of ammonia), DRIFTS (Diffuse Reflectance Infrared Fourier Transform Spectroscopy), XPS (X-ray Photoelectron Spectroscopy), and H2-TPR (H2-Total Physical Response). It was found that the crystalline phase of Fe2O3 formed was influenced by the presence of CTAB in the preparation process, which favored the formation of crystalline γ-Fe2O3. Owing to the changed structure, the redox-acid properties of FeM0.3Ox-C catalysts were modified, with higher exposure of acid sites and improved ability of NO oxidation to NO2 at low-temperature, both of which also contributed to the improvement of NOx conversion. In addition, the weakened redox ability of Fe prevented the over-oxidation of NH3, thus accounting for the greatly improved high-temperature activity as well as N2 selectivity.

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Section: Acidity and Redox Ability 241 Acidic Propertiesmentioning

confidence: 99%

Iron-Based Composite Oxide Catalysts Tuned by CTAB Exhibit Superior NH3–SCR Performance

et al. 2021

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“…Figure 8(b) shows the Fe 2p core‐level binding energy spectra of the catalysts, the two main peaks occurred at 711 eV and 724 eV were assigned to the Fe 2p 3/2 and Fe 2p 1/2 binding energy, respectively, [36] the separation of the 2p doublet was 13 eV. Besides, the satellite peak at about 717.0 eV could be observed obviously, proving the present of Fe 2 O 3 in all catalysts, [37] which was consistent with the reports in other literatures. By the peak‐fitting deconvolution technique, the Fe 2p 3/2 spectra could be fitted into two characteristic peaks, the peaks around 711.1 eV was assigned to the Fe 2+ ion, and the peak center at 713.1 e might be ascribed to Fe 3+ ions [38] .…”

Section: Resultsmentioning

confidence: 84%

Low‐Temperature NH₃ Selective Catalytic Reduction Performance Enhancement of Fe‐Based Oxides by Employing Carbon Nanotubes to Decorate the MgFe‐LDH

Liu

et al. 2023

ChemistrySelect

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In this study, a series of Mg3Fe1‐layered double oxide/xcarbon nanotubes (Mg3Fe1‐LDO/xCNTs) catalysts were constructed from the topological shift of Mg3Fe1‐layered double hydroxide (Mg3Fe1‐LDH) precursor. The as‐prepared catalysts were innovatively evaluated as potential candidates for low temperature selective catalytic reduction of NO with NH3 (NH3‐SCR). It was found that Mg3Fe1/10CNTs catalyst exhibited superb NH3‐SCR activity, with NOx conversion exceeding 80 % at low temperatures (180–270 °C). Moreover, excellent durability and stability towards SO2 was obtained. Such high catalytic efficiency can be attributed to the proper surface acidity and redox capacity of the catalyst, which might be correlated with higher dispersion and more appropriate valence distribution of Fe species caused by the moderate CNTs doping content. This work provides a fundamental understanding on Fe3+/Fe2+ synergistic effect of NH3‐SCR, which is propitious for the rational design and optimization of Fe‐based oxide low‐temperature denitrification (de‐NOx) catalysts.

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“…While after being activated by acid leaching (3V/ACFA), the amounts of NH 3 desorption increased to 260 μmol/g, and the peak of NH 3 desorption shifted to 344 °C. This suggested that acid leaching improved the adsorption of gaseous NH 3 and the formation of active NH 3 -adsorbed intermediates, thereby promoting the activity of the SCR reaction . Moreover, compared with 3V/RCFA and 3V/ACFA, the amounts of NH 3 desorbed over the 3V/MC-CFA catalyst increased to 505 μmol/g, and the peak of NH 3 desorption shifted to 295 °C.…”

Section: Resultsmentioning

confidence: 99%

Green and Moderate Activation of Coal Fly Ash and Its Application in Selective Catalytic Reduction of NO with NH₃

Zhang

et al. 2022

Environ. Sci. Technol.

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Coal fly ash (CFA) is an ideal source for the preparation of heterogeneous catalysts due to its abundant silicon and aluminum oxides, but its activity needs to be improved. In this study, a green and moderate approach for CFA activation was proposed, and a series of CFA-based catalysts were prepared for NO selective catalytic reduction (SCR). The results indicated that CFA could be well activated via mechanochemical activation with 3 h of milling duration in 1 mol/L of acetic acid, and 90% of NO removal was achieved over the CFA-based catalyst in 250 to 375 °C. Two activating mechanisms, i.e., the enhanced CFA fragmentation and the motivated Al dissolution, were revealed during the mechanochemical activation. The former facilitated the formation of mesopores and the exposure of Fe components in CFA fragments, which enhanced the capacity of oxygen storage over the as-activated catalyst. The latter motivated the formation of Si−OH groups, which promoted the migration of electrons and the dispersion of V species, thereby increasing the capacity of NH 3 adsorption over the as-obtained catalyst. Therefore, the performance of NO reduction was improved. The proposed activating approach could be a promising integration for CFA disposal and NO removal from inside coal-fired power plants.

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Selective catalytic reduction of NO by NH3 over Fe2O3-promoted V2O5/TiO2-based catalysts with high Fe2O3-to-V2O5 ratios

Cited by 10 publications

References 52 publications

Iron-Based Composite Oxide Catalysts Tuned by CTAB Exhibit Superior NH3–SCR Performance

Iron-Based Composite Oxide Catalysts Tuned by CTAB Exhibit Superior NH3–SCR Performance

Low‐Temperature NH₃ Selective Catalytic Reduction Performance Enhancement of Fe‐Based Oxides by Employing Carbon Nanotubes to Decorate the MgFe‐LDH

Green and Moderate Activation of Coal Fly Ash and Its Application in Selective Catalytic Reduction of NO with NH₃

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Selective catalytic reduction of NO by NH3 over Fe2O3-promoted V2O5/TiO2-based catalysts with high Fe2O3-to-V2O5 ratios

Cited by 10 publications

References 52 publications

Iron-Based Composite Oxide Catalysts Tuned by CTAB Exhibit Superior NH3–SCR Performance

Iron-Based Composite Oxide Catalysts Tuned by CTAB Exhibit Superior NH3–SCR Performance

Low‐Temperature NH3 Selective Catalytic Reduction Performance Enhancement of Fe‐Based Oxides by Employing Carbon Nanotubes to Decorate the MgFe‐LDH

Green and Moderate Activation of Coal Fly Ash and Its Application in Selective Catalytic Reduction of NO with NH3

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Low‐Temperature NH₃ Selective Catalytic Reduction Performance Enhancement of Fe‐Based Oxides by Employing Carbon Nanotubes to Decorate the MgFe‐LDH

Green and Moderate Activation of Coal Fly Ash and Its Application in Selective Catalytic Reduction of NO with NH₃