In situ XAS and IR studies on Cu:SAPO-5 and Cu:SAPO-11: the contributory role of monomeric linear copper(i) species in the selective catalytic reduction of NOx by propene

2009 ◽  
Vol 11 (26) ◽  
pp. 5476 ◽  
Author(s):  
Karina Mathisen ◽  
Michael Stockenhuber ◽  
David G. Nicholson
Keyword(s):  
Selective Catalytic Reduction ◽  
Catalytic Reduction ◽  
Ir Studies ◽  
In Situ Xas ◽  
Reduction Of Nox

scholarly journals The promotional role of Ce in Cu/ZSM-5 and in situ surface reaction for selective catalytic reduction of NOx with NH3

RSC Advances ◽  
2015 ◽  
Vol 5 (110) ◽  
pp. 90235-90244 ◽  
Author(s):  
Shuangshuang Lai ◽  
Dongmei Meng ◽  
Wangcheng Zhan ◽  
Yun Guo ◽  
Yanglong Guo ◽  
...  
Keyword(s):  
Selective Catalytic Reduction ◽  
Surface Reaction ◽  
Catalytic Reduction ◽  
Catalytic Performance ◽  
Incipient Wetness Impregnation ◽  
Impregnation Method ◽  
Reduction Of No ◽  
Reduction Of Nox

Ce doped Cu/ZSM-5 catalysts were prepared by the incipient-wetness-impregnation method, and the effect of Ce doping on the structure and the catalytic performance was investigated in detail for the selective catalytic reduction of NO with NH3

scholarly journals In Situ DRIFTS Studies of NH3-SCR Mechanism over V2O5-CeO2/TiO2-ZrO2 Catalysts for Selective Catalytic Reduction of NOx

Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1307 ◽  
Author(s):  
Yaping Zhang ◽  
Xiupeng Yue ◽  
Tianjiao Huang ◽  
Kai Shen ◽  
Bin Lu
Keyword(s):  
Selective Catalytic Reduction ◽  
Catalytic Reduction ◽  
Nox Reduction ◽  
Oxygen Storage ◽  
In Situ Drifts ◽  
Nh3 Scr ◽  
Nh3 Adsorption ◽  
Reduction Of Nox ◽  
Zro2 Catalyst

TiO2-ZrO2 (Ti-Zr) carrier was prepared by a co-precipitation method and 1 wt. % V2O5 and 0.2 CeO2 (the Mole ratio of Ce to Ti-Zr) was impregnated to obtain the V2O5-CeO2/TiO2-ZrO2 catalyst for the selective catalytic reduction of NOx by NH3. The transient activity tests and the in situ DRIFTS (diffuse reflectance infrared Fourier transform spectroscopy) analyses were employed to explore the NH3-SCR (selective catalytic reduction) mechanism systematically, and by designing various conditions of single or mixing feeding gas and pre-treatment ways, a possible pathway of NOx reduction was proposed. It was found that NH3 exhibited a competitive advantage over NO in its adsorption on the catalyst surface, and could form an active intermediate substance of -NH2. More acid sites and intermediate reaction species (-NH2), at lower temperatures, significantly promoted the SCR activity of the V2O5-0.2CeO2/TiO2-ZrO2 catalyst. The presence of O2 could promote the conversion of NO to NO2, while NO2 was easier to reduce. The co-existence of NH3 and O2 resulted in the NH3 adsorption strength being lower, as compared to tests without O2, since O2 could occupy a part of the active site. Due to CeO2’s excellent oxygen storage-release capacity, NH3 adsorption was weakened, in comparison to the 1 wt. % V2O5-0.2CeO2/TiO2-ZrO2 catalyst. If NOx were to be pre-adsorbed in the catalyst, the formation of nitrate and nitro species would be difficult to desorb, which would greatly hinder the SCR reaction. All the findings concluded that NH3-SCR worked mainly through the Eley-Rideal (E-R) mechanism.

Selective Catalytic Reduction of NOx: Mechanistic Perspectives on the Role of Base Metal and Noble Metal Ion Substitution

2008 ◽  
Vol 47 (23) ◽  
pp. 9240-9247 ◽  
Author(s):  
Sounak Roy ◽  
A. Marimuthu ◽  
Parag A. Deshpande ◽  
M. S. Hegde ◽  
Giridhar Madras
Keyword(s):  
Selective Catalytic Reduction ◽  
Base Metal ◽  
Noble Metal ◽  
Metal Ion ◽  
Catalytic Reduction ◽  
Ion Substitution ◽  
Reduction Of Nox

scholarly journals Methane-to-methanol conversion over zeolite Cu-SSZ-13, and its comparison with the selective catalytic reduction of NOx with NH3

2018 ◽  
Vol 8 (4) ◽  
pp. 1028-1038 ◽  
Author(s):  
Ramon Oord ◽  
Joel E. Schmidt ◽  
Bert M. Weckhuysen
Keyword(s):  
Selective Catalytic Reduction ◽  
Active Site ◽  
Catalytic Reduction ◽  
Methanol Conversion ◽  
Nuclear Site ◽  
Ft Ir ◽  
Reduction Of Nox

Using in situ FT-IR and operando UV-vis-NIR DRS, performed on a series of different Cu–ion-exchanged SSZ-13 zeolites, both a mono-nuclear site or a dimeric copper active site are consistent for methane-to-methanol activation.

Computational Insights into the Mechanism of the Selective Catalytic Reduction of NOx: Fe- Versus Cu-Doped Zeolite Catalysts

2019 ◽  
Author(s):  
Julian Rudolph ◽  
Christoph R. Jacob
Keyword(s):  
Selective Catalytic Reduction ◽  
Catalytic Reduction ◽  
Zeolite Catalysts ◽  
Reaction Pathways ◽  
Half Cycle ◽  
Computational Results ◽  
Comprehensive Picture ◽  
Cu Catalysts ◽  
Reduction Of Nox

<div> <div> <div> <p>We computationally investigate the mechanism of the reduction half-cycle of the selective catalytic reduction (SCR) of nitrogen oxides with ammonia. We compare both Fe- and Cu-doped zeolite catalysts and aim at exploring all accessible reaction pathways. From our calculations, a comprehensive picture emerges that unifies sev- eral previous mechanistic proposals. We find that both for Fe and for Cu catalysts, different reaction pathways are feasible, but some of the possible reaction pathways differ in these two cases. Our computational results provide a basis for the inter- pretation of in situ spectroscopic investigations that can possibly distinguish the different mechanistic pathways. </p> </div> </div> </div>

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