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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.


Papers
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Journal ArticleDOI
TL;DR: In this paper, a series of supported ceria-based catalysts for NH3-SCR were synthesized and then used as supports to prepare CeO2/TiO2-A, C O O O 2/Ti O 2-B, and C O 2 O 2O 2-R catalysts.
Abstract: Anatase (A) TiO2 is widely used as a support of the supported vanadium-based and non-vanadium-based catalysts for NH3-SCR reaction. However, there is lack of enough attention for brookite (B) and rutile (R) TiO2. Therefore, in the present work, we synthesize a series of TiO2-A, TiO2-B, and TiO2-R, and then used as supports to prepare CeO2/TiO2-A, CeO2/TiO2-B, and CeO2/TiO2-R catalysts with the purpose of clarifying the crystal form effect of TiO2 supports on the physicochemical properties and catalytic performance of these supported ceria-based catalysts for NH3-SCR reaction. Characterization results exhibit that H2 consumption (responding to reduction property), acid amounts, surface Ce3+ content, surface adsorbed oxygen species, and catalytic performance of these supported ceria-based catalysts give the order of CeO2/TiO2-R > CeO2/TiO2-B > CeO2/TiO2-A, which is related to the interaction (i.e., Ce3+ + Ti4+ ↔ Ce4+ + Ti3+) between CeO2 and TiO2 (anatase, brookite, and rutile). Especially, CeO2/TiO2-R catalyst exhibits the optimal catalytic performance for NH3-SCR reaction among these supported ceria-based catalysts owing to the most excellent reduction property as well as the largest amounts of acid sites, surface Ce3+ content, and surface adsorbed oxygen species.

160 citations

Patent
02 Sep 2004
TL;DR: In this paper, an exhaust emission purifying apparatus is provided with an electro-generative-heat carrier provided on an upstream side of an injection nozzle that supplies the reducing agent into the exhaust emission on upstream of a reduction catalyst in an exhaust pipe.
Abstract: In order to suppress deposition of constituent of a reducing agent (dissolved matter) in an exhaust passage of an engine enhancing an elimination rate of NOx even when temperature of an exhaust emission from the engine is low, an exhaust emission purifying apparatus is provided with an electro-generative-heat carrier provided on an upstream side of an injection nozzle that supplies the reducing agent into the exhaust emission on upstream side of a reduction catalyst in an exhaust pipe, the exhaust emission being heated to a temperature equal to or higher than a melting point of the dissolved matter whereby deposition of the dissolved matter on an inner wall surface of the exhaust pipe is suppressed to effectively use the supplied reducing agent for catalytic reduction reaction, even when the exhaust emission temperature is lower than the melting point of the dissolved matter of the reducing agent.

159 citations

Journal ArticleDOI
TL;DR: In this article, the influence of Fe doped over activated carbon (AC) supported Mn-Ce oxide catalysts was investigated for low-temperature selective catalytic reduction (SCR) of NO with NH3.

159 citations

Journal ArticleDOI
TL;DR: A predictive mechanism for elemental mercury (Hg0) oxidation on selective catalytic reduction (SCR) catalysts in coal-fired utility gas cleaning systems, given the ammonia (NH3)/nitric oxide (NO) ratio and concentrations of Hg0 and HCl at the monolith inlet, themonolith pitch and channel shape, and the SCR temperature and space velocity is introduced.
Abstract: This paper introduces a predictive mechanism for elemental mercury (Hg0) oxidation on selective catalytic reduction (SCR) catalysts in coal-fired utility gas cleaning systems, given the ammonia (NH3)/nitric oxide (NO) ratio and concentrations of Hg0 and HCl at the monolith inlet, the monolith pitch and channel shape, and the SCR temperature and space velocity. A simple premise connects the established mechanism for catalytic NO reduction to the Hg0 oxidation behavior on SCRs: that hydrochloric acid (HCl) competes for surface sites with NH3 and that Hg0 contacts these chlorinated sites either from the gas phase or as a weakly adsorbed species. This mechanism explicitly accounts for the inhibition of Hg0 oxidation by NH3, so that the monolith sustains two chemically distinct regions. In the inlet region, strong NH3 adsorption minimizes the coverage of chlorinated surface sites, so NO reduction inhibits Hg0 oxidation. But once NH3 has been consumed, the Hg0 oxidation rate rapidly accelerates, even w...

158 citations

Journal ArticleDOI
TL;DR: The mechanism of selective catalytic oxidation (SCO) of NH3 over Ag/Al2O3 was studied by NH3 temperature-programed oxidation, O-2-pulse adsorption, and in situ DRIFTS of NH-3 adaption and oxidation.

158 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023311
2022632
2021546
2020583
2019604
2018595