Activity enhancement of WO3 modified Fe2O3 catalyst for the selective catalytic reduction of NO  by NH3

Liu, Zhiming; Su, Hang; Chen, Biaohua; Li, Junhua; Woo, Seong Ihl

doi:10.1016/j.cej.2016.04.100

Cited by 214 publications

(64 citation statements)

References 49 publications

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“…To replace V 2 O 5 ‐based catalysts due to their toxicity,, transition metal oxide catalysts that are environmentally benign have been developed . Among them, Fe 2 O 3 ‐based catalysts, the active component of which is often maghemite (γ‐Fe 2 O 3 ) or hematite (α‐Fe 2 O 3 ), are typical owing to their harmless feature and SO 2 ‐tolerance . Although γ‐Fe 2 O 3 often shows higher SCR activity than α‐Fe 2 O 3 , it is still less active than V 2 O 5 ‐based SCR catalysts particularly at low reaction temperatures.…”

Section: Introductionmentioning

confidence: 99%

Simultaneously Enhancing Stability and Activity of Maghemite via Site‐Specific Ti(IV) Doping for NO Emission Control

Chen

et al. 2018

ChemCatChem

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Maghemite (γ‐Fe2O3) is an environmentally benign catalyst for selective catalytic reduction (SCR) of NO with NH3, but its poor stability and low activity hamper its application in real NO emission control. Herein, we developed a stable Ti4+ doped γ‐Fe2O3 catalyst (Ti‐γ‐Fe2O3) by site‐specific Ti4+ doping at the octahedral sites rather than tetrahedral active sites (Fe3+Td), as substantiated by synchrotron room‐temperature X‐ray diffraction (SXRD) data. In situ SXRD and thermogravimetric analysis (TG) data demonstrate that Ti4+ cations occupying part of the octahedral sites lead to enhanced thermal stability of Ti‐γ‐Fe2O3 with respect to γ‐Fe2O3, thus enabling Ti‐γ‐Fe2O3 to stably operate at 400 °C under simulated normal SCR conditions. Fe L3‐edge and O K‐edge X‐ray absorption spectra show that the high‐valence Ti4+ doping lengthens the Fe3+Td‐O bonds, and activates the lattice oxygen species, thus improving the SCR activity. This work provides a feasible strategy for designing environmentally benign Fe2O3‐based SCR catalysts with significant stability and high catalytic activity.

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Section: Introductionmentioning

confidence: 99%

Simultaneously Enhancing Stability and Activity of Maghemite via Site‐Specific Ti(IV) Doping for NO Emission Control

Chen

et al. 2018

ChemCatChem

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“…The change is more pronounced after adding Ca, indicating that doping Ca promoter effectively inhibits agglomeration of Fe 2 O 3 phase during impregnation and calcination. Liu et al [32] reported that strong interaction between Fe species and additives contributes to a shift of Raman peaks to a lower wavenumber, owing to electron transfer from promoter to Fe 2 O 3 . In contrast, few changes in peak location of Raman spectra were observed in this study, excluding electronic effect of promoters on Fe 2 O 3 species.…”

Section: Resultsmentioning

confidence: 99%

Effect of Ca Promoter on the Structure and Catalytic Behavior of FeK/Al₂O₃ Catalyst in Fischer‐Tropsch Synthesis

et al. 2019

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Fischer‐Tropsch synthesis (FTS) to olefins is an alternative route for lower olefins production. The role of alkaline‐earth metals as promoters in FTS was not so clear. Herein, we prepared a series of FeKCa/Al2O3 catalysts by excessive co‐impregnation method to elucidate the promotion effect of Ca on catalytic performance. Characterization technologies of N2 physisorption, XRD, Raman spectrum, TEM and CO chemisorption were used to study the textural properties, phase composition and dispersion of Fe species. The results showed that the addition of Ca promotes dispersion of iron species thus leads to much smaller crystallite size. Meanwhile, no electron donation effect was observed upon Ca introduction, as evidenced by XPS and H2‐TPR. A maximum of FTY is achieved at 1.0 wt.% Ca, followed by a decline when adding excessive Ca due to less exposed active sites. Notably, the product distribution is almost unchanged. The nearly constant TOF values with and without Ca addition indicates Ca works only as a structural promoter rather than chemical promoter.

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“…have demonstrated that the low‐temperature catalytic performance of FeMnO x is remarkable higher than MnO x , indicating that Fe 2 O 3 can provide redox sites to improve the activation of NH 3 and NO x . According to Liu et al, the synergetic effect between Fe and Ce contributed to the formation of reactive intermediate species, leading to the high catalytic deNO x performance of the Fe‐Ce‐Ti mixed oxide catalyst, furthermore, it was reported that the WO 3 /Fe 2 O 3 catalyst exhibited high NH 3 ‐SCR activity in a wide range of operating temperatures and high resistance against H 2 O and SO 2 .…”

Section: Introductionmentioning

confidence: 92%

Silicotungstic acid modified Ce‐Fe‐O_x catalyst for selective catalytic reduction of NO_x with NH₃: Effect of the amount of HSiW

Song

Xing

Zhang

et al. 2019

Applied Organom Chemis

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The HSiW(x)/Ce‐Fe catalysts were used to research the effect of silicotungstic acid contents on the catalytic activity in the selective catalytic reduction of NOx with NH3. Doping different contents of silicotungstic acid affected surface species and redox property as well as the catalytic activity. With the increasing amount of HSiW (x = 5%, 10% and 20%), the redox reaction between Fe3+/Fe2+ and Ce4+/Ce3+ enhanced, which could improve the ratio of Ce3+ and Fe3+. And then, more Ce3+ increased the ratio of chemisorbed oxygen (Oα). Besides, the type and strength of acid sites over HSiW(x)/Ce‐Fe was affected by the HSiW contents. These factors facilitated the catalytic performance. Thus, the NOx conversion of HSiW(x)/Ce‐Fe(x = 20%) was higher than 90%, which maintained in a wide temperature range between 200 and 400 °C.

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Activity enhancement of WO3 modified Fe2O3 catalyst for the selective catalytic reduction of NO by NH3

Cited by 214 publications

References 49 publications

Simultaneously Enhancing Stability and Activity of Maghemite via Site‐Specific Ti(IV) Doping for NO Emission Control

Simultaneously Enhancing Stability and Activity of Maghemite via Site‐Specific Ti(IV) Doping for NO Emission Control

Effect of Ca Promoter on the Structure and Catalytic Behavior of FeK/Al₂O₃ Catalyst in Fischer‐Tropsch Synthesis

Silicotungstic acid modified Ce‐Fe‐O_x catalyst for selective catalytic reduction of NO_x with NH₃: Effect of the amount of HSiW

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Activity enhancement of WO3 modified Fe2O3 catalyst for the selective catalytic reduction of NO by NH3

Cited by 214 publications

References 49 publications

Simultaneously Enhancing Stability and Activity of Maghemite via Site‐Specific Ti(IV) Doping for NO Emission Control

Simultaneously Enhancing Stability and Activity of Maghemite via Site‐Specific Ti(IV) Doping for NO Emission Control

Effect of Ca Promoter on the Structure and Catalytic Behavior of FeK/Al2O3 Catalyst in Fischer‐Tropsch Synthesis

Silicotungstic acid modified Ce‐Fe‐Ox catalyst for selective catalytic reduction of NOx with NH3: Effect of the amount of HSiW

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Effect of Ca Promoter on the Structure and Catalytic Behavior of FeK/Al₂O₃ Catalyst in Fischer‐Tropsch Synthesis

Silicotungstic acid modified Ce‐Fe‐O_x catalyst for selective catalytic reduction of NO_x with NH₃: Effect of the amount of HSiW