Topic
Selective catalytic reduction
About: Selective catalytic reduction is a research topic. Over the lifetime, 10502 publications have been published within this topic receiving 226291 citations.
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TL;DR: In this article, titanate nanotubes (TNTs) were used to tune the property of Mn-Ce composite oxides and led to an outstanding catalytic performance in selective catalytic reduction of NO by NH 3 within middle temperature region.
67 citations
TL;DR: CeSmOx mixed oxide catalysts supported on TiO 2 prepared by coprecipitation method were used for selective catalytic reduction of NOx with NH 3, and the results showed that the addition of Sm could effectively enhance the low-temperature SCR activity and SO 2 /H 2 O resistance of Ce/TiO 2 catalyst, and the appropriate mole ratio of Sm to Ce was 0.3.
67 citations
Patent•
30 Nov 2005TL;DR: In this paper, the authors present a method of controlling NOx emissions by supplying ammonia to the exhaust passage at a location upstream of a first selective catalytic reduction catalyst, where the amount of ammonia supplied at the first location is less than about 90% of the effective amount of ammonium needed for reduction of all NOx at the second location.
Abstract: A first aspect of the present disclosure includes a method of controlling nitric oxides emissions. The method may include producing an exhaust gas stream containing NOx and supplying the exhaust gas stream to an exhaust passage. The method may further comprise supplying ammonia to the exhaust passage at a location upstream of a first selective catalytic reduction catalyst, wherein the amount of ammonia supplied at the first location is less than about 90% of the effective amount of ammonia needed for reduction of all NOx at the first location. Further, ammonia may be supplied to the exhaust passage at a second location downstream of the first selective catalytic reduction catalyst and upstream of a second selective catalytic reduction catalyst.
67 citations
TL;DR: In this article, a series of CHA-type Fex/Cu-SSZ-13 catalysts were prepared by liquid ion exchange method based on the one-pot synthesized Cu-SSz-13 catalyst and applied to the selective catalytic reduction of NO with NH3.
Abstract: A series of CHA-type Fex/Cu-SSZ-13 catalysts were prepared by liquid ion exchange method based on the one-pot synthesized Cu-SSZ-13 catalyst. The catalysts were applied to the selective catalytic reduction of NO with NH3 and were characterized by means of XRD, N2 adsorption–desorption, UV-Vis-DRS, H2-TPR, XPS and in situ DRIFTS. Fex/Cu-SSZ-13 catalysts achieved high NH3-SCR activity, excellent N2 selectivity from 150 °C to 550 °C, high hydrothermal stability and were highly resistant to high space velocity. The results may be attributed to the synergistic effects between copper and iron species. The results of H2-TPR, UV-Vis DRS and XPS indicated that more active sites and stronger redox capacity contributed to the excellent NH3-SCR performance upon the addition of Fe species into Cu-SSZ-13. In situ DRIFTS results showed that NO+ and NO3− generated from NO + O2 adsorption were the key intermediates and were further reduced to N2 by NH3.
67 citations
TL;DR: In this article, the activity and hydrothermal stability of Cu-SAPO-34 and CuCe-SapO-Ce for selective catalytic reduction of NO x with ammonia (NH 3 -SCR) were investigated systematically, which indicated that Ce mainly existed on the surface of the catalyst and was well dispersed in the form of Ce 3+, and its interaction with copper could improve the dispersion of copper species and increase the amount of isolated Cu 2+ ions.
Abstract: The activity and hydrothermal stability of Cu-SAPO-34 and CuCe-SAPO-34 for selective catalytic reduction of NO x with ammonia (NH 3 -SCR) were investigated systematically The catalysts were prepared by wet-impregnation method, and characterized by N 2 adsorption, X-ray diffraction (XRD), X-ray photoelectron spectrum (XPS), Ultraviolet-visible diffuse reflectance spectrum (UV–vis-DRS), H 2 -temperature programmed reduction (H 2 -TPR) and NH 3 -temperature programmed desorption (NH 3 -TPD) The experimental results of fresh catalysts suggested that Ce mainly existed on the surface of the catalyst and was well dispersed in the form of Ce 3+ , and its interaction with copper could improve the dispersion of copper species and increase the amount of isolated Cu 2+ ions, so that CuCe-SAPO-34 performed better NH 3 -SCR activity than Cu-SAPO-34 After hydrothermal aging at 800 °C for 12 h, the characterization results indicated that the introduction of cerium effectively improved the textural and structural stability of SAPO-34 since more cations at the exchange site of SAPO-34 could decrease the concentration of Si O(H) Al bond which was closely related to the damage of the SAPO-34 framework Moreover, the addition of Ce could prevent the decrease of acid densities, promote the redistribution of CuO during hydrothermal aging and provide higher amount of isolated Cu 2+ ions, leading to superior hydrothermal stability of CuCe-SAPO-34 catalyst
67 citations