Experimental assessment of the bifunctional NH3-SCR pathway and the structural and acid-base properties of WO3 dispersed on CeO2 catalysts

Iwasaki, M.; Dohmae, Kazuhiko; Nagai, Yasutaka; Sudo, Eiichi; Tanaka, Toŝhiyuki

doi:10.1016/j.jcat.2017.12.032

Cited by 62 publications

(47 citation statements)

References 63 publications

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“…The number of weak and mid-strong acid sites may also determine the NH3-SCR activity at different temperatures. When the Sm content is too high, the strength of acidity is too strong for the reaction to proceed, i.e., the NH3 adsorbed on the strong acidic sites is unfavorable for the NH3-SCR reaction, which is in accordance with previously reported results [39,40].…”

Section: Surface Acidities Of the Catalystssupporting

confidence: 92%

Comprehensive understanding of the superior performance of Sm-modified Fe2O3 catalysts with regard to NO conversion and H2O/SO2 resistance in the NH3-SCR reaction

Sun

Chen

Jia

et al. 2021

Chinese Journal of Catalysis

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Section: Surface Acidities Of the Catalystssupporting

confidence: 92%

Comprehensive understanding of the superior performance of Sm-modified Fe2O3 catalysts with regard to NO conversion and H2O/SO2 resistance in the NH3-SCR reaction

Sun

Chen

Jia

et al. 2021

Chinese Journal of Catalysis

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“…Adsorption and activation of gaseous NH 3 on the surface acid sites of catalyst play a key role in NH 3 ‐SCR reaction at low temperatures . Therefore, NH 3 ‐TPD experiments were carried out.…”

Section: Resultsmentioning

confidence: 99%

“…Adsorption and activation of gaseous NH 3 on the surface acid sites of catalyst play a key role in NH 3 -SCR reaction at low temperatures. [49][50][51] Therefore, NH 3 -TPD experiments were carried out. Figure 12 indicates that there is only one big desorption peak in the NH 3 -TPD profiles for the three catalysts.…”

Section: Nh 3 -Tpd Analysismentioning

confidence: 99%

Effect of Mn addition on the low‐temperature NH₃‐selective catalytic reduction of NO_x over Fe₂O₃/activated coke catalysts: Experiment and mechanism

Song

Zhu

Sun

et al. 2018

Asia-Pacific J Chem Eng

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Fe2O3/activated coke (AC) and Mn–Fe2O3/AC catalysts were prepared by an impregnation method for the low‐temperature selective catalytic reduction of nitrogen oxides (NOx) with ammonia (NH3). These catalysts were characterized by X‐ray fluorescence, X‐ray diffraction, isothermal N2 adsorption/desorption, X‐ray photoelectron spectroscopy, temperature program reduction by H2, and temperature programmed desorption of NH3 methods. Experimental results show that Fe2O3/AC catalyst with Mn addition exhibits an excellent NOx conversion at low temperature. Nearly more than 94.7% NOx conversion of 8Mn6Fe/AC catalyst was obtained at 180–240°C. The results of NH3 transient reaction and adsorption capacity of NOx indicate that 8Mn6Fe/AC catalyst has the capacity to adsorb gaseous NH3 and NOx on the catalyst surface. 6Fe/AC catalyst with a certain amount addition of Mn increases the dispersion of γ‐Fe2O3 phase, and ratios of Fe3+/(Fe2+ + Fe3+) and Oβ/(Oβ + Oα) obtained good reducibility and a lot of acid sites, which play important roles in improving the NOx conversion. The influences of SO2 and H2O on the NOx conversion over 8Mn6Fe/AC catalyst were also investigated. The good H2O poisoning resistance was obtained.

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“…Guan et al [71] prepared nanocomposite Ti 0.9 Ce 0.05 V 0.05 O 2Àd catalysts through a solution combustion route. The redox properties of Ce 4 + /Ce 3 + are recognized to enhance the rate of NO oxidation NO 2 strongly kinetically limited at low temperature [81] then reaching optimal NO/ NO x = 0.5 corresponding to the fast-SCR conditions. [82] These authors characterized from in situ IR spectroscopic measurements the formation of active monodentate and bidentate nitrates species which can react with adsorbed NH 4 + species bonded to Brønsted acid sites.…”

Section: Thermally Resistant Bulk V-scr Systemsmentioning

confidence: 99%

What News in the Surface Chemistry of Bulk and Supported Vanadia Based SCR‐Catalysts: Improvements in their Resistance to Poisoning and Thermal Sintering

Granger

Siaka

Umbarkar

2018

The Chemical Record

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This paper reports a short review on the impact of poisoning effects and thermal aging on the reactivity of surface vanadate species on benchmark V2O5−WO3/TiO2 Selective‐Catalytic‐Reduction catalysts. A renewed interest of this SCR technology is related to its diversification notably as after‐treatment systems to treat the exhaust from Diesel engines with higher running temperature especially when SCR catalysts are coated on Diesel Particulates Filters. Particular attention is also paid to poisoning effects in conjunction with the progressive replacement of fossil fuels by bio‐fuels containing alkaline contaminants which drastically deactivate the catalyst through neutralization of strong acid sites. Most of the investigations show that better insight into the mechanisms of poisoning and aging processes is needed especially to understand the relative sensibility of various vanadate species. This could provide original guidelines to catalyst preparation and or the developments of more stable bulk systems as exemplified.

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Experimental assessment of the bifunctional NH3-SCR pathway and the structural and acid-base properties of WO3 dispersed on CeO2 catalysts

Cited by 62 publications

References 63 publications

Comprehensive understanding of the superior performance of Sm-modified Fe2O3 catalysts with regard to NO conversion and H2O/SO2 resistance in the NH3-SCR reaction

Comprehensive understanding of the superior performance of Sm-modified Fe2O3 catalysts with regard to NO conversion and H2O/SO2 resistance in the NH3-SCR reaction

Effect of Mn addition on the low‐temperature NH₃‐selective catalytic reduction of NO_x over Fe₂O₃/activated coke catalysts: Experiment and mechanism

What News in the Surface Chemistry of Bulk and Supported Vanadia Based SCR‐Catalysts: Improvements in their Resistance to Poisoning and Thermal Sintering

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Experimental assessment of the bifunctional NH3-SCR pathway and the structural and acid-base properties of WO3 dispersed on CeO2 catalysts

Cited by 62 publications

References 63 publications

Comprehensive understanding of the superior performance of Sm-modified Fe2O3 catalysts with regard to NO conversion and H2O/SO2 resistance in the NH3-SCR reaction

Comprehensive understanding of the superior performance of Sm-modified Fe2O3 catalysts with regard to NO conversion and H2O/SO2 resistance in the NH3-SCR reaction

Effect of Mn addition on the low‐temperature NH3‐selective catalytic reduction of NOx over Fe2O3/activated coke catalysts: Experiment and mechanism

What News in the Surface Chemistry of Bulk and Supported Vanadia Based SCR‐Catalysts: Improvements in their Resistance to Poisoning and Thermal Sintering

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Effect of Mn addition on the low‐temperature NH₃‐selective catalytic reduction of NO_x over Fe₂O₃/activated coke catalysts: Experiment and mechanism