scispace - formally typeset
Search or ask a question
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.


Papers
More filters
Patent
16 Aug 2002
TL;DR: In this article, a metal-promoted zeolite beta catalyst is used for selective catalytic reduction of nitrogen oxides with ammonia in which the zeolites beta is pre-treated so as to provide improved hydrothermal stability.
Abstract: The present invention is directed to a metal-promoted zeolite beta catalyst useful in the selective catalytic reduction of nitrogen oxides with ammonia in which the zeolite beta is pre-treated so as to provide the zeolite with improved hydrothermal stability. The stabilized beta zeolite is provided by incorporating into the zeolite structure non-framework aluminum oxide chains. The aluminum oxide chains can be incorporated into the zeolite structure by a unique steaming regimen or by treatment with rare earth metals, such as cerium. The treatment process is unlike well-known methods of dealuminizing zeolites for the purpose of increasing the silica to alumina ratio. In the present invention, the non-framework aluminum oxide is characterized by FT-IR by a peak at 3781+2 cm-1, which when present, stabilizes the zeolite against further dealumination such as under oxidizing and harsh hydrothermal conditions.

110 citations

Journal ArticleDOI
TL;DR: In this article, the selective catalytic reduction of nitric oxide with ammonia was studied using Fe 2 O 3, Cr 2 O3 and CuO loaded active carbons as catalysts in the presence and absence of oxygen.
Abstract: The selective catalytic reduction of nitric oxide with ammonia was studied using Fe 2 O 3 , Cr 2 O 3 and CuO loaded active carbons as catalysts in the presence and absence of oxygen at reaction temperatures between 100 and 500°C. Active carbons pretreated with concentrated nitric acid showed a higher catalytic activity in SCR than catalysts which were oxidized in air. The ash content (from 0.2 to 7.1 wt.%) of different unloaded active carbons had no effect on the catalytic activity below 300°C in the absence of oxygen. However, in the presence of oxygen an increasing ash content resulted in an increase in activity. Transition-metal oxide loading led to an increase in SCR activity, especially in the absence of oxygen. An increasing transition-metal content from 1 to 10 wt.% improved the activity as well. The presence of oxygen in the reaction mixture enhanced the conversion of nitric oxide especially in the low-temperature range between 100 and 200°C. Activity and selectivity of the respective catalysts were influenced by the type of metal oxide: in the presence of oxygen, catalysts with 10 wt.% Fe were the most active and selective.

110 citations

Journal ArticleDOI
TL;DR: In this article, a comparative study was carried out on a small-pore Cu-CHA and a large-pores Cu-BEA zeolite catalyst to understand the lower N 2 O formation on smallpore CHA supported Cu catalysts in the selective catalytic reduction (SCR) of NOx with NH 3.

109 citations

Journal ArticleDOI
TL;DR: The reaction mechanism of NO reduction by propene over silver-supported TiO2-ZrO2 catalyst was studied by means of in situ FT-IR, combined with catalytic activity studies as mentioned in this paper.

109 citations

Journal ArticleDOI
TL;DR: In this paper, the performance of a mixed ceria-titanium catalysts doping tin was investigated for selective catalytic reduction (SCR) of NO with NH3, which exhibited an extraordinarily wide operation window ranging from 180 to 460°C and better the tolerance of H2O or SO2.
Abstract: Ternary mixed ceria-titanium catalysts doping tin were synthesized by a solvothermal method and applied to selective catalytic reduction (SCR) of NO with NH3. The Sn doping catalyst showed better low-temperature activity compared with unmodified catalyst, which exhibited an extraordinarily wide operation window ranging from 180 to 460 °C and better the tolerance of H2O or SO2. Powder X-ray diffraction (XRD), laser Raman spectroscopy (Raman), fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), transmission electron microscope (TEM), BET surface area by N2-adsorption-desorption, hydrogen temperature-programmed reduction (H2-TPR), ammonia temperature-programmed desorption (NH3-TPD) were performed to study the structure, redox ability and surface acidity for the CeSnTiOx catalyst. Notably, the addition of Sn could prominently modify and optimize the structure of mixed metal oxides. Meanwhile, it was verified that synergistic interaction between of Ce and Sn surprisingly produced, and crystal defects, oxygen vacancies, acid sites as well as the specific surface areas evidently increased. In addition, the uniform pore channel was also beneficial to NH3-SCR. Especially, the electron interaction between Sn and Ce in reaction could greatly improve the SCR performance and H2O/SO2 durability.

109 citations


Network Information
Related Topics (5)
Catalysis
400.9K papers, 8.7M citations
92% related
Photocatalysis
67K papers, 2.1M citations
90% related
Adsorption
226.4K papers, 5.9M citations
86% related
Oxide
213.4K papers, 3.6M citations
82% related
Aqueous solution
189.5K papers, 3.4M citations
82% related
Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023311
2022632
2021546
2020583
2019604
2018595