New Insight into the Effects of NH3 on SO2 Poisoning for In Situ Removal of Metal Sulfates in Low-Temperature NH3-SCR over an Fe–V Catalyst

Er-modified FeMn/TiO2 catalysts were prepared through the wet impregnation method, and their NH3-SCR activities were tested. The results showed that Er modification could obviously promote SO2 resistance of FeMn/TiO2 catalysts at a low temperature. The promoting effect and mechanism were explored in detail using various techniques, such as BET, XRD, H2-TPR, XPS, TG, and in-situ DRIFTS. The characterization results indicated that Er modification on FeMn/TiO2 catalysts could increase the Mn4+ concentration and surface chemisorbed labile oxygen ratio, which was favorable for NO oxidation to NO2, further accelerating low-temperature SCR activity through the “fast SCR” reaction. As fast SCR reaction could accelerate the consumption of adsorbed NH3 species, it would benefit to restrain the competitive adsorption of SO2 and limit the reaction between adsorbed SO2 and NH3 species. XPS results indicated that ammonium sulfates and Mn sulfates formed were found on Er-modified FeMn/TiO2 catalyst surface seemed much less than those on FeMn/TiO2 catalyst surface, suggested that Er modification was helpful for reducing the generation or deposition of sulfate salts on the catalyst surface. According to in-situ DRIFTS the results of, the presence of SO2 in feeding gas imposed a stronger impact on the NO adsorption than NH3 adsorption on Lewis acid sites of Er-modified FeMn/TiO2 catalysts, gradually making NH3-SCR reaction to proceed in E–R mechanism rather than L–H mechanism. DRIFTS.

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Insight into the SO2 poisoning mechanism for NOx removal by NH3-SCR over Cu/LTA and Cu/SSZ-13

Chemical Engineering Journal ◽

10.1016/j.cej.2020.125048 ◽

2020 ◽

Vol 395 ◽

pp. 125048 ◽

Cited By ~ 1

Author(s):

Aiyong Wang ◽

Louise Olsson

Keyword(s):

Nox Removal ◽

Nh3 Scr ◽

So2 Poisoning ◽

Insight Into

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Low temperature high activity of M (M = Ce, Fe, Co, Ni) doped M-Mn/TiO2 catalysts for NH3-SCR and in situ DRIFTS for investigating the reaction mechanism

Applied Surface Science ◽

10.1016/j.apsusc.2020.146014 ◽

2020 ◽

Vol 515 ◽

pp. 146014 ◽

Cited By ~ 5

Author(s):

Shangzhi Xie ◽

Lulu Li ◽

Lijian Jin ◽

Yaohui Wu ◽

Hao Liu ◽

...

Keyword(s):

Reaction Mechanism ◽

Low Temperature ◽

High Activity ◽

In Situ Drifts ◽

Nh3 Scr

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In Situ DRIFTS Investigation on CeOx Catalyst Supported by Fly-Ash-Made Porous Cordierite Ceramics for Low-Temperature NH3-SCR of NOX

Catalysts ◽

10.3390/catal9060496 ◽

2019 ◽

Vol 9 (6) ◽

pp. 496 ◽

Cited By ~ 4

Author(s):

Shaoxin Wang ◽

Ziwei Chen ◽

Beini He ◽

Zheng Yan ◽

Hao Wang ◽

...

Keyword(s):

Fly Ash ◽

Low Temperature ◽

Photoelectron Spectroscopy ◽

Active Sites ◽

Supported Catalyst ◽

Nh3 Scr ◽

Scr Catalysts ◽

Cordierite Ceramics ◽

Porous Cordierite

A series of CeOx catalysts supported by commercial porous cordierite ceramics (CPCC) and synthesized porous cordierite ceramics (SPCC) from fly ash were prepared for selective catalytic reduction of NOx with ammonia (NH3-SCR). A greater than 90% NOx conversion rate was achieved by the SPCC supported catalyst at 250–300 °C when the concentration of loading precursor was 0.6 mol/L (denoted as 0.6Ce/SPCC), which is more advantageous than the CPCC supported ones. The EDS mapping results reveal the existence of evenly distributed impurities on the surface of SPCC, which hence might be able to provide more attachment sites for CeOx particles. Further measurements with temperature programmed reduction by hydrogen (H2-TPR) demonstrate more reducible species on the surface of 0.6Ce/SPCC, thus giving rise to better NH3-SCR performance at a low-temperature range. The X-ray photoelectron spectroscopy (XPS) analyses reveal that the Ce atom ratio is higher in 0.6Ce/SPCC, indicating that a higher concentration of catalytic active sites could be found on the surface of 0.6Ce/SPCC. The in situ diffused reflectance infrared fourier transform spectroscopy (DRIFTS) results indicate that the SCR reactions over 0.6Ce/SPCC follow both Eley-Rideal (E-R) and Langmuir-Hinshelwood (L-H) mechanisms. Hence, the SPCC might be a promising candidate to provide support for NH3-SCR catalysts, which also provide a valuable approach to recycling the fly ash.

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A Fortuitous, Mild Catalytic Carbon–Carbon Bond Hydrogenolysis by a Phosphine-Free Catalyst

Australian Journal of Chemistry ◽

10.1071/ch15792 ◽

2016 ◽

Vol 69 (5) ◽

pp. 561 ◽

Cited By ~ 2

Author(s):

Loorthuraja Rasu ◽

Ben Rennie ◽

Mark Miskolzie ◽

Steven H. Bergens

Keyword(s):

Low Temperature ◽

Room Temperature ◽

Nmr Studies ◽

Carbon Bond ◽

Mild Conditions ◽

Carbon Carbon Bond ◽

Diamine Ligands ◽

Insight Into

The putative catalyst trans-[Ru((S,S)-skewphos)(H)2((R,R)-dpen)] (skewphos = 2,4-bis(diphenylphosphino)pentane; dpen = 1,2-diphenylethylenediamine) transforms the trifluoroacetyl amide 2,2,2-trifluoro-1-(piperidin-1-yl)ethanone under mild conditions (4 atm H2, room temperature, 4–24 h, 1 mol-% Ru, 15 mol-% KOtBu in tetrahydrofuran) to generate the formylated amine 1-formylpiperidine and fluoroform via C–C bond hydrogenolysis. Catalysts are also prepared by reacting cis-[Ru(η3-C3H5)(MeCN)2(COD)]BF4 (COD = 1,5-cyclooctadiene) with diamine ligands in situ. Low-temperature NMR studies provided insight into this reaction.

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Mesoporous Mn–Ti amorphous oxides: a robust low-temperature NH3-SCR catalyst

Catalysis Science & Technology ◽

10.1039/c8cy01313f ◽

2018 ◽

Vol 8 (24) ◽

pp. 6396-6406 ◽

Cited By ~ 17

Author(s):

Yanran Yang ◽

Minghong Wang ◽

Zuliang Tao ◽

Qing Liu ◽

Zhaoyang Fei ◽

...

Keyword(s):

Low Temperature ◽

Freeze Drying ◽

Amorphous Oxides ◽

Scr Catalyst ◽

Nh3 Scr

Mn–Ti amorphous oxides prepared by the combinedin situdeposition and freeze-drying strategy exhibited excellent activities and stability in low-temperature NH3-SCR.

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