Fe and/or Mn oxides supported on fly ash-derived SBA-15 for low-temperature NH3-SCR

Li, Ge; Wang, Baodong; Wang, Hongyan; Ma, Jing; Xu, Wayne Qiang; Lü, Yonglong; Han, Yi‐Fan; Sun, Qi

doi:10.1016/j.catcom.2018.01.035

Cited by 62 publications

(25 citation statements)

References 33 publications

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“…Although the CuO/MnO 2 -mTiO 2 catalyst had good tolerance to H 2 O, the resistance to SO 2 and H 2 O/SO 2 poisoning, as well as high space velocity (GHSV), still need to be enhanced for practical use. Li et al [135] synthesized fly ash-derived SBA-15 mesoporous molecular sieves supported Fe and/or Mn catalysts, and reported that Fe-Mn/SBA-15 catalyst showed notably greater NH 3 -SCR activity than Mn/SBA-15 or Fe/SBA-15 in the temperature range of 150-250 • C. Moreover, the Fe-Mn/SBA-15 catalyst exhibited good time-on-stream stability (200 h) and water tolerance at 200 • C. The high metal dispersion, Mn 4+ /Mn 3+ ratio, the concentration of adsorbed oxygen, and the redox activity are important features to enhance the NH 3 -SCR performance of the Fe-Mn/SBA-15 catalyst. In their subsequent study, the authors investigated the mechanisms of NO reduction and N 2 O formation using in-situ DRIFT and transient reaction studies and proposed a possible denitration mechanism over the Fe-Mn/SBA-15 catalyst which is shown in Figure 25.…”

Section: Supported Binary and Multi Transition Metal-based Catalystsmentioning

confidence: 99%

Section: Supported Binary and Multi Transition Metal-based Catalystsmentioning

confidence: 99%

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A Review of Low Temperature NH3-SCR for Removal of NOx

et al. 2019

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The importance of the low-temperature selective catalytic reduction (LT-SCR) of NOx by NH3 is increasing due to the recent severe pollution regulations being imposed around the world. Supported and mixed transition metal oxides have been widely investigated for LT-SCR technology. However, these catalytic materials have some drawbacks, especially in terms of catalyst poisoning by H2O or/and SO2. Hence, the development of catalysts for the LT-SCR process is still under active investigation throughout seeking better performance. Extensive research efforts have been made to develop new advanced materials for this technology. This article critically reviews the recent research progress on supported transition and mixed transition metal oxide catalysts for the LT-SCR reaction. The review covered the description of the influence of operating conditions and promoters on the LT-SCR performance. The reaction mechanism, reaction intermediates, and active sites are also discussed in detail using isotopic labelling and in situ FT-IR studies.

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Section: Supported Binary and Multi Transition Metal-based Catalystsmentioning

confidence: 99%

Section: Supported Binary and Multi Transition Metal-based Catalystsmentioning

confidence: 99%

A Review of Low Temperature NH3-SCR for Removal of NOx

et al. 2019

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“…The disadvantage of V 2 O 5 −WO 3 (MoO 3 )/TiO 2 is the strict temperature window limit [7]. These vanadium-based catalysts are not efficient enough to eliminate NO x as the catalytic temperature below 250 • C. In recent years, the catalysts suitable for the low temperature SCR have become required, and are appropriately installed in a downstream electrostatic precipitator and desulfurizer [8]. Many research groups dedicated to utilizing high efficient active elements and structure supports to optimize low-temperature SCR catalysts with super activities, excellent stabilities and wide-ranging temperature windows.…”

Section: Introductionmentioning

confidence: 99%

“…, where [NO x ] = [NO] + [NO 2 ]. The NH 3 conversion rate was calculated by the inlet and outlet NH 3 concentrations, and the N 2 selectivity was calculated by the concentrations of N 2 O and NO x , as show in Equations(7)and(8) [51][52][53]. Each experiment was repeated three times to assure the results' accuracy.NO x conversion rate = [NO x ] in − [NO x ] out [NO x ] in ×100% (6) NH 3 conversion rate = [NH 3 ] in − [NH 3 ] out [NH 3 ] in ×100% ] in − [NO x ] out ×100%(8)…”

mentioning

confidence: 99%

Structure–Activity Relationship Study of Mn/Fe Ratio Effects on Mn−Fe−Ce−Ox/γ-Al2O3 Nanocatalyst for NO Oxidation and Fast SCR Reaction

et al. 2018

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A series of Mn−Fe−Ce−Ox/γ-Al2O3 nanocatalysts were synthesized with different Mn/Fe ratios for the catalytic oxidation of NO into NO2 and the catalytic elimination of NOx via fast selective catalytic reduction (SCR) reaction. The effects of Mn/Fe ratio on the physicochemical properties of the samples were analyzed by means of various techniques including N2 adsorption, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), H2-temperature-programmed reduction (TPR), NH3-temperature-programmed desorption (TPD) and NO-TPD, meanwhile, their catalytic performance was also evaluated and compared. Multiple characterizations revealed that the catalytic performance was highly dependent on the phase composition. The Mn15Fe15−Ce/Al sample with the Mn/Fe molar ratio of 1.0 presented the optimal structure characteristic among all tested samples, with the largest surface area, increased active components distributions, the reduced crystallinity and diminished particle sizes. In the meantime, the ratios of Mn4+/Mnn+, Fe2+/Fen+ and Ce3+/Cen+ in Mn15Fe15−Ce/Al samples were improved, which could enhance the redox capacity and increase the quantity of chemisorbed oxygen and oxygen vacancy, thus facilitating NO oxidation into NO2 and eventually promoting the fast SCR reaction. In accord with the structure results, the Mn15Fe15−Ce/Al sample exhibited the highest NO oxidation rate of 64.2% at 350 °C and the broadest temperature window of 75–350 °C with the NOx conversion >90%. Based on the structure–activity relationship discussion, the catalytic mechanism over the Mn−Fe−Ce ternary components supported by γ-Al2O3 were proposed. Overall, it was believed that the optimization of Mn/Fe ratio in Mn−Fe−Ce/Al nanocatalyst was an extremely effective method to improve the structure–activity relationships for NO pre-oxidation and the fast SCR reaction.

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“…Among all the studied zeolites, SBA-15 mesoporous molecular sieves (MMS) have attracted the most attention due to their larger specific surface area (690-1040 m 2 /g), larger pore size (4.6-30 nm), and better hydrothermal stability [13][14][15][16][17][18] . In our previous work [19][20][21] , Fe-Mn/ SBA-15 catalysts were prepared using a fly ash-derived SBA-15 MMS as a support and tested for NH 3 -SCR. The 11.2Fe-11Mn/ SBA-15 catalyst exhibits high NH 3 -SCR activities at 150-250°C.…”

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confidence: 99%

Aluminium-induced component engineering of mesoporous composite materials for low-temperature NH3-SCR

Wang

et al. 2020

Commun Chem

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Supported Mn 2 O 3 is useful in achieving high dinitrogen selectivity at low temperature during ammonia-selective catalytic reduction (SCR). However, its controlled synthesis is challenging when the supporting material is the conventional pure silicon SBA-15 mesoporous molecular sieve. Here we show that silicon and aluminium in fly ash, the solid waste produced by coalfired power plants, can be used to synthesize an Al-SBA-15 mesoporous molecular sieve support, which can guide the growth of Mn 2 O 3 in the as-synthesized Fe-Mn/Al-SBA-15 NH 3-SCR catalyst. Its superior catalytic performance is demonstrated by the high NO x conversion (≥90%) and selectivity (≥86%) at low temperatures (150-300°C). The combined theoretical and experimental results reveal that the introduction of Al induces the growth of Mn 2 O 3 catalysts. Our findings, therefore, provide a strategy for the rational design of lowtemperature NH 3-SCR catalysts through dopant-induced component engineering of composite materials.

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Fe and/or Mn oxides supported on fly ash-derived SBA-15 for low-temperature NH3-SCR

Cited by 62 publications

References 33 publications

A Review of Low Temperature NH3-SCR for Removal of NOx

A Review of Low Temperature NH3-SCR for Removal of NOx

Structure–Activity Relationship Study of Mn/Fe Ratio Effects on Mn−Fe−Ce−Ox/γ-Al2O3 Nanocatalyst for NO Oxidation and Fast SCR Reaction

Aluminium-induced component engineering of mesoporous composite materials for low-temperature NH3-SCR

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