Effect of Sulfation on the Selective Catalytic Reduction of NO with NH3 Over γ-Fe2O3

Huang, Hao; Lan, Yi; Shan, Wenpo; Qi, Feihong; Xiong, Shangcao; Liao, Yong; Fu, Yuwu; Yang, Shijian

doi:10.1007/s10562-013-1174-4

Cited by 34 publications

(32 citation statements)

References 27 publications

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“…The good performance is ascribed to the existence of active component of iron-manganese oxides. The performance of iron-manganese oxides had been documented in previous reports (Kim et al, 2012;Yang et al, 2013;Huang et al, 2014;Huang et al, 2016). Generally, iron oxides possessed a good performance at the temperature of 300-400°C, while manganese oxides exhibited a good performance at the temperature of 150-250°C.…”

Section: Scr Performancementioning

confidence: 67%

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Characterization and SCR Performance of Nano-Structured Iron-Manganese Oxides: Effect of Annealing Temperature

Chen

et al. 2017

Aerosol Air Qual. Res.

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Nano-structured iron-manganese oxides composite was prepared by annealing of natural Mn-rich limonite at different temperatures (500, 600, 700, 800°C). Their SCR performances of NO removal by NH 3 were evaluated, and SEM, TEM, XRD, XRF, BET, XPS, Raman, NH 3 -TPD were utilized to analyze the catalytic mechanism. The results indicated that after annealing at 500°C, the as-prepared iron-manganese oxides exhibited the best SCR performance in NO conversion and N 2 selectivity (over 80%) at the temperature window of 150-300°C. An increase in annealing temperature from 500 to 800°C significantly increased the particle size resulting in the decrease of surface areas, active sites, and then SCR performances. The experimental results suggested the natural Mn-rich limonite was an excellent precursor for preparing iron-manganese oxides and possessed excellent SCR performance of NO removal by NH 3 . This study will provide a novel way for the preparation of SCR catalyst and exploit a new application field for natural limonite.

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Section: Scr Performancementioning

confidence: 67%

“…In the previous reports, iron oxide catalysts mostly contained α-Fe 2 O 3 (Liu et al, 2017), γ-Fe 2 O 3 (Yang et al, 2013;Huang et al, 2014) and rod-shaped Fe 2 O 3 (Mou et al, 2012). The results indicated that iron oxides catalyst exhibited an excellent SCR performance at a temperature range of 200-400°C.…”

Section: Introductionmentioning

confidence: 78%

Characterization and SCR Performance of Nano-Structured Iron-Manganese Oxides: Effect of Annealing Temperature

Chen

et al. 2017

Aerosol Air Qual. Res.

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“…Therefore, all peaks present in Figure b to d could be ascribed to the reduction of iron species. Previous studies indicated that for magnetic Fe 2 O 3 ‐500, the former peak in the low‐temperature range was attributed to the reduction of Fe 2 O 3 to Fe 3 O 4 , and the latter large broad peak in the high‐temperature range was attributed to further reduction of Fe 3 O 4 to FeO and partial Fe 0 . Similar to magnetic Fe 2 O 3 ‐500, magnetic Fe 0.75 Ti 0.25 O z ‐500 also showed an obvious reduction peak in the range of 300 ‐ 500 °C and another large broad peak in the range of 500 ‐ 850 °C appeared.…”

Section: Resultsmentioning

confidence: 82%

“…The O 1s peaks on magnetic Fe 1‐ x Ti x O z ‐500 ( x = 0, 0.25, 0.5, 0.75, and 1) catalysts mainly centered at about 529.5, 530.2, and 532.1 eV. The O 1s peaks at about 529.5 and 530.2 eV were attributed to O 2− in transition metal oxides and −OH, respectively, the O 1s peaks at about 532.1 eV could be assigned to O 2− in SO 4 2− , and the S 2p peaks mainly centered at about 169 eV (shown in Figure S1D, Supporting Information) attributed to SO 4 2− . During the washing process of the precursors, the precursors obtained by co‐precipitation were only washed with distilled water for several times in order to avoid oxidization of Fe(OH) 2 to α‐Fe 2 O 3 by O 2 from atmosphere.…”

Section: Resultsmentioning

confidence: 97%

Microwave‐Pyrolysis‐Assisted Preparation of Magnetic Iron‐Titanium Mixed Oxide Catalyst for Selective Catalytic Reduction of NO_x with NH₃

Zhou

Xiong

et al. 2017

CLEAN Soil Air Water

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A kind of magnetic iron‐titanium oxide catalyst for selective catalytic reduction (SCR) of NOx with NH3 is obtained by the microwave‐pyrolysis co‐precipitation method. This catalyst is characterized in detail by various techniques such as X‐ray diffraction, N2 adsorption–desorption, X‐ray photoelectron spectroscopy, temperature‐programmed reduction of H2, and temperature‐programmed desorption of NH3/NO to investigate the influence of titanium oxide addition on the NH3‐SCR activity of magnetic iron oxide. Furthermore, the NH3‐SCR reaction mechanism over magnetic iron‐titanium oxide is also revealed. The NH3‐SCR activity over magnetic iron oxide is enhanced by the addition of titanium oxide, especially the low‐temperature activity. The addition of titanium oxide depresses the oxidization of γ‐Fe2O3 to α‐Fe2O3 in the precursor obtained through microwave‐pyrolysis co‐precipitation during the aging process, and also reduces the absorption ability of SO42− to the precursor. The crystallite of iron oxide in magnetic Fe1‐xTixOz‐500 (x = 0.25, 0.5, and 0.75) catalysts is mainly γ‐Fe2O3. Among these magnetic catalysts, magnetic Fe0.75Ti0.25Oz‐500 has two distinctive peaks in the pore size distribution curve and more active iron‐based sites on its surface for NH3‐SCR reaction. This catalyst shows the highest NH3‐SCR activity. The NH3‐SCR reaction over magnetic Fe0.75Ti0.25Oz‐500 at low‐temperature obeys both the Eley–Rideal mechanism and the Langmuir–Hinshelwood mechanism.

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“…The reported iron oxide catalysts primarily contained α-Fe 2 O 3 (Liu et al, 2013a), γ-Fe 2 O 3 (Huang et al, 2013;Yang et al, 2013), rod-shaped Fe 2 O 3 (Mou et al, 2012) and Fe-based catalyst including Fe-ZSM-5 (Brandenberger et al, 2010), Fe/HBEA , Fe-Ti-V spinel , Fe-Ti spinel (Yang et al, 2016), and Fe-Mn oxides . The results indicated that the Fe-based oxide catalyst exhibit excellent SCR performance in a temperature range of 200-400°C.…”

Section: Introductionmentioning

confidence: 99%

Novel Method for Preparing Controllable Nanoporous a-Fe2O3 and its Reactivity to SCR De-NOx

Zhang

et al. 2017

Aerosol Air Qual. Res.

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Controllable nanoporous hematite (CNH, α-Fe 2 O 3 ) was prepared by thermal treatment of α-FeOOH at different temperatures, and the SCR activity of the prepared α-Fe 2 O 3 was evaluated. XRD (X-ray diffraction), HRTEM (highresolution transmission electron microscopy), N 2 adsorption-desorption, XPS (X-ray photoelectron spectroscopy), and NH 3 -TPD (NH 3 -temperature programmed desorption) were utilized to characterize the catalysts. The results indicated that after thermal treatment at less than 600°C, the α-Fe 2 O 3 catalysts exhibited excellent NO conversion that was higher than 80% in a temperature range from 300 to 400°C. CNH400 with a relatively large surface area of 47.24 m 2 g -1 and many surface hydroxyl groups did not exhibit a substantially improved SCR activity even though it exhibited the best SCR activity. Therefore, the L-H mechanism was not the main reaction route for SCR of NO by α-Fe 2 O 3 . The increasing crystallization of α-Fe 2 O 3 decreased the SCR activity, indicating that a decrease in surface oxygen defects was important for the SCR of NO and fitting the E-R mechanism. The NH 3 -TPD and XPS (O1s) results confirmed this hypothesis. This study provides an approach for the design and preparation of a controllable nanoporous α-Fe 2 O 3 catalyst for SCR of NO by NH 3 .

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Effect of Sulfation on the Selective Catalytic Reduction of NO with NH3 Over γ-Fe2O3

Cited by 34 publications

References 27 publications

Characterization and SCR Performance of Nano-Structured Iron-Manganese Oxides: Effect of Annealing Temperature

Characterization and SCR Performance of Nano-Structured Iron-Manganese Oxides: Effect of Annealing Temperature

Microwave‐Pyrolysis‐Assisted Preparation of Magnetic Iron‐Titanium Mixed Oxide Catalyst for Selective Catalytic Reduction of NO_x with NH₃

Novel Method for Preparing Controllable Nanoporous a-Fe2O3 and its Reactivity to SCR De-NOx

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Effect of Sulfation on the Selective Catalytic Reduction of NO with NH3 Over γ-Fe2O3

Cited by 34 publications

References 27 publications

Characterization and SCR Performance of Nano-Structured Iron-Manganese Oxides: Effect of Annealing Temperature

Characterization and SCR Performance of Nano-Structured Iron-Manganese Oxides: Effect of Annealing Temperature

Microwave‐Pyrolysis‐Assisted Preparation of Magnetic Iron‐Titanium Mixed Oxide Catalyst for Selective Catalytic Reduction of NOx with NH3

Novel Method for Preparing Controllable Nanoporous a-Fe2O3 and its Reactivity to SCR De-NOx

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Microwave‐Pyrolysis‐Assisted Preparation of Magnetic Iron‐Titanium Mixed Oxide Catalyst for Selective Catalytic Reduction of NO_x with NH₃