Selective catalytic reduction of nitrogen oxides by ammonia on iron oxide catalysts

Apostolescu, Nicolae; Geiger, Bastian; Khan, Hizbullah; Jan, M.T.; Kureti, Sven; Reichert, D.; Schott, Florian J.P.; Weisweiler, Werner

doi:10.1016/j.apcatb.2005.07.004

Cited by 230 publications

(167 citation statements)

References 35 publications

Supporting

Mentioning

157

Contrasting

Unclassified

Order By: Relevance

“…[5,6] TEM analyses of the catalyst after the stability test confirm that both the morphology and the exposed facets are almost the same as the fresh one (Figure 3 c). Electron energy-loss spectroscopy (EELS) reaffirmed that the oxidation state of iron and the coordination of oxygen in the catalyst keep unchanged before and after the reaction (Table S1 in the Supporting Information), indicating the stable surface coordination environment.…”

mentioning

confidence: 63%

“…This mature system displays adequate activity typically at 300-400 8C, but it is still not satisfactory with respect to the volatility and toxicity of VO x and the easy deactivation. [1][2][3] Attracted by the inherently environmentally benign character and the prominent thermal stability, ferric oxides have long been explored to catalyze selective reduction of NO x with ammonia, [3][4][5][6][7][8] but no significant progress has been achieved so far. Ferric oxides commonly suffer from the insufficient activity at low temperatures and the severe deactivation induced by H 2 O and SO 2 that are permanently and abundantly present in the exhaust.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Rod‐Shaped Fe₂O₃ as an Efficient Catalyst for the Selective Reduction of Nitrogen Oxide by Ammonia

et al. 2012

View full text Add to dashboard Cite

Nanorust: Fe2O3 nanomaterials with controllable crystal phase and morphology have been successfully fabricated. The γ‐Fe2O3 nanorods that are enclosed by the reactive {110} and {100} facets are highly active and distinctively stable for selective catalytic reduction of NO with NH3. The picture shows the shape and surfaces and the surface atomic configurations of the preferentially exposed {110} and {001} planes.

show abstract

mentioning

confidence: 63%

mentioning

confidence: 99%

Rod‐Shaped Fe₂O₃ as an Efficient Catalyst for the Selective Reduction of Nitrogen Oxide by Ammonia

et al. 2012

View full text Add to dashboard Cite

show abstract

“…Several years ago, Apostolescu et al 47 developed a new supported-type Fe 2 O 3 /WO 3 /ZrO 2 catalyst achieving total NO x conversion and high N 2 selectivity in the NH 3 -SCR reaction over the temperature range 280-430 1C. Based on a series of characterization results including XRD and H 2 -TPR, they pointed out that the Fe species in the Fe 2 O 3 /WO 3 /ZrO 2 catalyst were mainly present in the form of well-crystallized Fe 2 O 3 and also small Fe x O y particles.…”

Section: Introductionmentioning

confidence: 99%

Environmentally-benign catalysts for the selective catalytic reduction of NO_xfrom diesel engines: structure–activity relationship and reaction mechanism aspects

2014

View full text Add to dashboard Cite

Selective catalytic reduction of NO x using NH 3 or hydrocarbons (NH 3 -SCR or HC-SCR) in oxygen-rich exhaust from diesel engines remains a major challenge in environmental catalysis. The development of highly efficient, stable and environmentally-benign catalysts for SCR processes is very important for practical use. In this feature article, the structure-activity relationship of vanadium-free catalysts in the NH 3 -SCR reaction is discussed in detail, including Fe-, Ce-based oxide catalysts and Fe-, Cu-based zeolite catalysts, which is beneficial for catalyst redesign and activity improvement. Based on our research, a comprehensive mechanism contributing to the performance of Ag/Al 2 O 3 in HC-SCR is provided, giving a clue to the design of a catalytic system with high efficiency.

show abstract

“…Fe exchanged zeolite catalysts usually show good SCR activity in the high temperature range with remarkable H 2 O and SO 2 durability, such as Fe-ZSM-5 by Ma and Gru¨nert 10 and Fe-Ce-ZSM-5 by Carja et al 11 Other Fe-based catalysts are mainly Fe 2 O 3 loaded types such as Fe 2 O 3 -TiO 2 by Kato et al 12 and Fe 2 O 3 -WO 3 /ZrO 2 by Apostolescu et al 13 with excellent SCR activity and H 2 O/SO 2 durability in the medium temperature range. Based on the idea of combining the predominant SCR activity, thermal stability and N 2 selectivity of Fe-based catalysts and the excellent SO 2 durability of TiO 2 , here we present a novel non-toxic catalyst using an iron titanate crystallite as the active component with a broad operation window in the medium temperature range (200-400 1C) under relatively high space velocities.…”

mentioning

confidence: 99%

Novel iron titanate catalyst for the selective catalytic reduction of NO with NH3 in the medium temperature range

2008

View full text Add to dashboard Cite

An iron titanate catalyst with a crystallite phase, prepared by a co-precipitation method, showed excellent activity, stability, selectivity and SO 2 /H 2 O durability in the selective catalytic reduction of NO with NH 3 in the medium temperature range.Nitrogen oxides (NO x ) have become a major source of air pollution which can result in photochemical smog, acid rain and ozone depletion and have strong respiratory toxicity endangering human health.1 Stringent environmental legislation has been made worldwide to reduce NO x emitted from mobile and stationary resources including vehicles and coal-fired power plants. Selective catalytic reduction of NO with NH 3 (NH 3 -SCR) is an effective and economical method to remove NO and nowadays the most widely used catalyst system is V 2 O 5 -WO 3 /TiO 2 or V 2 O 5 -MoO 3 /TiO 2 with a relatively narrow temperature window of 350-400 1C.2 The problems of this system are as follows: the low N 2 selectivity in the high temperature range because of N 2 O formation and NH 3 overoxidation; the toxicity of vanadium pentoxide to the environment; and high conversion of SO 2 to SO 3 with increasing vanadium amounts, which can result in catalyst deactivation. 13 with excellent SCR activity and H 2 O/SO 2 durability in the medium temperature range. Based on the idea of combining the predominant SCR activity, thermal stability and N 2 selectivity of Fe-based catalysts and the excellent SO 2 durability of TiO 2 , here we present a novel non-toxic catalyst using an iron titanate crystallite as the active component with a broad operation window in the medium temperature range (200-400 1C) under relatively high space velocities. NO conversion at 300 1C remaining at 100% in the presence of 10% H 2 O and (or) 100 ppm SO 2 makes this catalyst a potential candidate for industrial applications.The iron titanate catalysts were prepared by the conventional co-precipitation method using Fe(NO 3 ) 3 Á9H 2 O and Ti(SO 4 ) 2 as precursors (Fe : Ti ¼ 1 : 1 in molar ratio) and 25 wt% NH 3 ÁH 2 O as precipitator with subsequent filtration, washing, and drying at 100 1C overnight and calcination at 400, 500, 600, 700 1C for 6 h, respectively (signified by Fe x TiO y -400, 500, 600, 700 1C). Catalysts sieved with 20-40 mesh were used in the activity test experiments and the reaction conditions were as follows: 0.6 ml sample, 500 ppm NO, 500 ppm NH 3 , 5% O 2 , 100 ppm SO 2 (when used), 10% H 2 O (when used), balance N 2 , 500 ml min À1 total flow rate and gas hourly space velocity (GHSV) ¼ 50 000 h À1. The water vapor was injected with an accurate syringe pump equipped with an evaporator which was heated to 300 1C. The tubing of the activity test system was heated to 120 1C to avoid deposition of ammonium salts and water droplets. The effluent gas, including NO, NH 3 , N 2 O and NO 2 dried using CaSO 4 was continuously analyzed by an FTIR spectrometer (Thermo Nicolet Corporation Nexus 670, OMNIC Quantpad software) equipped with a heated, low volume multiple-path gas cell (2 m). The spectra were collected...

show abstract

Selective catalytic reduction of nitrogen oxides by ammonia on iron oxide catalysts

Cited by 230 publications

References 35 publications

Rod‐Shaped Fe₂O₃ as an Efficient Catalyst for the Selective Reduction of Nitrogen Oxide by Ammonia

Rod‐Shaped Fe₂O₃ as an Efficient Catalyst for the Selective Reduction of Nitrogen Oxide by Ammonia

Environmentally-benign catalysts for the selective catalytic reduction of NO_xfrom diesel engines: structure–activity relationship and reaction mechanism aspects

Novel iron titanate catalyst for the selective catalytic reduction of NO with NH3 in the medium temperature range

Contact Info

Product

Resources

About

Selective catalytic reduction of nitrogen oxides by ammonia on iron oxide catalysts

Cited by 230 publications

References 35 publications

Rod‐Shaped Fe2O3 as an Efficient Catalyst for the Selective Reduction of Nitrogen Oxide by Ammonia

Rod‐Shaped Fe2O3 as an Efficient Catalyst for the Selective Reduction of Nitrogen Oxide by Ammonia

Environmentally-benign catalysts for the selective catalytic reduction of NOxfrom diesel engines: structure–activity relationship and reaction mechanism aspects

Novel iron titanate catalyst for the selective catalytic reduction of NO with NH3 in the medium temperature range

Contact Info

Product

Resources

About

Rod‐Shaped Fe₂O₃ as an Efficient Catalyst for the Selective Reduction of Nitrogen Oxide by Ammonia

Rod‐Shaped Fe₂O₃ as an Efficient Catalyst for the Selective Reduction of Nitrogen Oxide by Ammonia

Environmentally-benign catalysts for the selective catalytic reduction of NO_xfrom diesel engines: structure–activity relationship and reaction mechanism aspects