Iron Oxide and Chromia Supported on Titania-Pillared Clay for Selective Catalytic Reduction of Nitric Oxide with Ammonia

Cheng, Linda S.; Yang, Ralph T.; Chen, Ning

doi:10.1006/jcat.1996.0364

Cited by 102 publications

(43 citation statements)

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“…1 Pillared clays are particularly promising. [5][6][7] Pillared interlayer clay (PILC) is a unique two-dimensional, zeolite-like material. The early interest in PILC, because of its large pores, was in the possibility of replacing zeolite as the catalyst for fluid catalytic cracking (FCC), which operates at near 700 °C with high steam concentration.…”

Section: Discussionmentioning

confidence: 99%

“…The catalyst was prepared by incipient wetness impregnation, as described elsewhere. 7,8 The V 2 O 5 -WO 3 / TiO 2 catalyst had the same composition and surface area as a European commercial SCR catalyst, as described by Tuenter et al 15 In addition, this catalyst had SCR activity and behavior nearly identical to the commercial SCR catalyst made by a major catalyst manufacturer. Catalytic Activity Measurement The SCR activity measurement was carried out in a fixedbed quartz reactor.…”

Section: 48mentioning

confidence: 94%

“…7,13 The starting clay was a purified montmorillonite, that is, a purified-grade bentonite powder from Fisher Co., with particles less than or equal to 2 µm. The pillaring agent, a solution of partially hydrolyzed Ti-polycations, was prepared by first adding TiCl 4 into a 2 M HCl solution.…”

Section: 48mentioning

confidence: 99%

“…The iron ion-exchanged TiO 2 -PILC catalyst was prepared according to the procedure described above. Ceriumdoped Fe-TiO 2 -PILC was prepared by using the incipient wetness impregnation method 5,7 with cerium nitrate as the cerium precursor. Ce-Fe-TiO 2 -PILC catalyst was prepared by the following procedure: 2-g TiO 2 -PILC was exchanged with cerium ions (using 200 mL 0.02 M Ce(NO 3 ) 3 solution) for 20 hr, then exchanged with 0.05 M Fe(NO 3 ) 3 solution for 6 hr and repeated twice at room temperature.…”

Section: 48mentioning

confidence: 99%

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Superior Pillared Clay Catalysts for Selective Catalytic Reduction of Nitrogen Oxides for Power Plant Emission Control

Long

Yang

Zammit

2000

Journal of the Air & Waste Management Association

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ABSTRACT3+ -exchanged pillared clay is found to be the most active. The catalytic activity of Fe-TiO 2 -PILC could be further improved by the addition of a small amount of cerium ions or cerium oxide. H 2 O and SO 2 increase both the activity and the product selectivity to N 2 . The maximum activity on the Ce-Fe-TiO 2 -PILC is more than 3 times as active as that on a vanadium catalyst. Moreover, compared to the V 2 O 5 -WO 3 /TiO 2 catalyst, the Fe-TiO 2 -PILC catalysts show higher N 2 /N 2 O product selectivities and substantially lower activities (by ~85%) for SO 2 oxidation to SO 3 under the same reaction conditions. A 100-hr run in the presence of H 2 O and SO 2 for the CeO 2 /Fe-TiO 2 -PILC catalyst showed no decrease in activity. INTRODUCTIONSelective catalytic reduction (SCR) of nitrogen oxides (NO + NO 2 ) with NH 3 is of increasing commercial interest for stationary source applications. A large number of catalysts, such as V 2 O 5 -WO 3 (or MoO 3 )/TiO 2 , other transitionmetal oxides (e.g., Fe, Cr, Co, Ni, Cu, Nb), and doped catalysts, as well as zeolite-type catalysts (e.g., H-ZSM-5,

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Section: Discussionmentioning

confidence: 99%

Section: 48mentioning

confidence: 94%

Section: 48mentioning

confidence: 99%

Section: 48mentioning

confidence: 99%

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Superior Pillared Clay Catalysts for Selective Catalytic Reduction of Nitrogen Oxides for Power Plant Emission Control

Long

Yang

Zammit

2000

Journal of the Air & Waste Management Association

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“…Using TiO 2 -PILC as a support, a 3/1 (molar ratio) of Fe 2 O 3 /Cr 2 O 3 (total 10% wt.) showed an NH 3 SCR activity twice as high as that of the commercial V 2 O 5 /TiO 2 catalyst [63]. For HC SCR, Cu-ion exchanged PILC yielded activities higher than that of Cu-ZSM-5; and more significantly, its activity was only slightly decreased by H 2 O and SO 2 [57,58].…”

Section: Introductionmentioning

confidence: 99%

Pillared Clays as Superior Catalysts for Selective Catalytic Reduction of Nitric Oxide

Long¹,

Tharappiwattananon²,

Li³

et al. 2000

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Conclusion 973 DisclaimerThis report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views or opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. EXECUTIVE SUMMARYRemoval of NO x (NO + NO 2 ) from exhaust gases is a challenging subject. V 2 O 5 -based catalysts are commercial catalysts for selective catalytic reduction (SCR) with NH 3 for stationary sources. However, for diesel and lean-burn gasoline engines in vehicles, hydrocarbons would be the preferred reducing agents over NH 3 because of the practical problems associated with the use of NH 3 (i.e., handling and slippage through the reactor). The noble-metal three-way catalysts are not effective under these conditions. The first catalyst found to be active for selective catalytic reduction of NO by hydrocarbons in the presence of excess oxygen was copper exchanged ZSM-5 and other zeolites, reported in 1990 by Iwamoto in Japan and Held et al. in Germany. Although Cu-ZSM-5 is very active and the most intensively studied catalyst, it suffers from severe deactivation in engine tests, mainly due to H 2 O and SO 2 .In this project, we found that ion-exchanged pillared clays and MCM-41 catalysts showed superior SCR activities of NO with hydrocarbon. All Cu 2+ -exchanged pillared clays showed higher SCR activities than Cu-ZSM-5 reported in the literature. In particular, H 2 O and SO 2 only slightly deactivated the SCR activity of Cu-TiO 2 -PILC, whereas severe deactivation was observed for Cu-ZSM-5. Moreover, Pt/MCM-41 provided the highest specific NO reduction rates as compared with other Pt doped catalysts, i.e., Pt/Al 2 O 3 , Pt/SiO 2 and Pt/ZSM-5. ThePt/MCM-41 catalyst also showed a good stability in the presence of H 2 O and SO 2 . The results are described in detail in 4 chapters. 5In Chapter 1, we report SCR of NO by C 2 H 4 on ion-exchanged pillared clays, i.e., CuTiO 2 -PILC, Cu-Al 2 O 3 -PILC, Cu-ZrO 2 -PILC, Cu-Al 2 O 3 -Laponite, Fe-TiO 2 -PILC, Ce-TiO 2 -PILC, Co-TiO 2 -PILC, Ag-TiO 2 -PILC, Ga-TiO 2 -PILC. Cu-TiO 2 -PILC showed the highest activities at temperatures below 370 o C, while Cu-Al 2 O 3 -PILC was most active at above 370 o C, and both catalysts showed higher SCR activities than Cu-ZSM-5 reported in the literature.No detectable N 2 O was formed by all of these catalysts. The catalytic activity increased wi...

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Pillared Clays

Poncelet¹,

Fripiat²

2008

Handbook of Heterogeneous Catalysis

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The sections in this article are Introduction Historical Overview Which Clays or Smectites can be Pillared? Al ‐Pillared Vermiculites and Phlogopite Micas Reviews Pillaring Mechanisms Basic Pillaring Mechanism: Exchange Precipitation New Pillaring Mechanism: Template Pillars Homo‐Atomic Pillars A Hydroxyaluminum Polymer B Gallium and Mixed Gallium Aluminum Hydroxypolymers C Zirconia Hydroxypolymers D Titania Pillars E Silica and Silicate Pillars F Transition Metal Oxide Pillars Heteroatomic Pillars Mixed Al  Fe Pillars Miscellaneous Pillared Clays Preliminary Remarks Main Physical Characteristics Chemical Properties Chemical Modifications or Functionalization of the Pillaring Species Catalytic Properties A Brief Summary of Previous Studies An Overview of Catalytic Reactions Investigated during the Past Decade Conclusions Acknowledgments

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Iron Oxide and Chromia Supported on Titania-Pillared Clay for Selective Catalytic Reduction of Nitric Oxide with Ammonia

Cited by 102 publications

References 0 publications

Superior Pillared Clay Catalysts for Selective Catalytic Reduction of Nitrogen Oxides for Power Plant Emission Control

Superior Pillared Clay Catalysts for Selective Catalytic Reduction of Nitrogen Oxides for Power Plant Emission Control

Pillared Clays as Superior Catalysts for Selective Catalytic Reduction of Nitric Oxide

Pillared Clays

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