Insights into the impact of lanthanum on hydrothermal-induced migration and transformation of copper species in Cu/SAPO-34 catalyst for NH3-SCR

2021 ◽  
Vol 515 ◽  
pp. 111914
Author(s):  
Huimin Wang ◽  
Wei Li ◽  
Siyuan Xu ◽  
Mo Liu ◽  
Jiming Hao ◽  
...  
Keyword(s):  
Copper Species ◽  
Nh3 Scr ◽  
The Impact

Potassium deactivation of Cu-SSZ-13 catalyst for NH3-SCR: Evolution of salts, zeolite and copper species

2020 ◽  
Vol 383 ◽  
pp. 123080 ◽  
Author(s):  
Liping Liu ◽  
Xiaodong Wu ◽  
Yue Ma ◽  
Xu Zhang ◽  
Rui Ran ◽  
...  
Keyword(s):  
Copper Species ◽  
Nh3 Scr

Understanding the nature of NH3-coordinated active sites and the complete reaction schemes for NH3-SCR using Cu-SAPO-34 catalysts

2021 ◽  
Author(s):  
Guangpeng Yang ◽  
Jingyu Ran ◽  
Xuesen Du ◽  
Xiangmin Wang ◽  
Zhilin Ran ◽  
...  
Keyword(s):  
Low Temperature ◽  
Active Sites ◽  
Zeolite Catalysts ◽  
Copper Species ◽  
Nh3 Scr ◽  
Complete Reaction ◽  
Catalytic Capacity ◽  
Reaction Schemes

Cu-SAPO-34 zeolite catalysts show excellent NH3-SCR performance at low temperature, which is due to the catalytic capacity of copper species.

scholarly journals The Role of SO3 Poisoning in CU/SSZ-13 NH3-SCR Catalysts

Catalysts ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 741 ◽  
Author(s):  
Wang ◽  
Hou ◽  
Yan ◽  
Zhang ◽  
Wang ◽  
...  
Keyword(s):  
Copper Sulfate ◽  
Active Sites ◽  
Catalytic Reduction ◽  
Copper Ions ◽  
Acid Resistance ◽  
Temperature Program Reduction ◽  
Copper Species ◽  
Nh3 Scr ◽  
Scr Catalysts

To reveal the role of SO3 poisoning in Cu/SSZ-13 NH3-SCR catalysts, fresh and sulfated Cu/SSZ-13 catalysts were prepared in the presence or absence of SO3 flux. The deactivation mechanism is probed by the changes of structural, copper species, and selective catalytic reduction (SCR) activity. The variations concentrate on the changes of copper species as the Chabazite (CHA) framework of Cu/SSZ-13 catalysts could keep intact at high ratios of SO3/SOx. The thermal gravimetric analyzer (TGA) results reveal that the copper sulfate formed during sulfation and the amounts of sulfate species increased with an increase in the SO3/SOx ratio. In contrast to the changing trend of copper sulfate, temperature program reduction (H2-TPR), and electron paramagnetic resonance (EPR) results manifest that, since the number of active copper ions declines with an increase of the SO3/SOx ratio, the active sites transform to these inactive species during sulfation. Due to the combination of NH3-SCR activity and the kinetic tests, it is shown that the decreased number of active sites is responsible for the declined SCR activity at low temperature. As Cu/SSZ-13 catalysts show excellent acid-resistance ability, our study reveals that the Cu/SSZ-13 catalyst is a good candidate for NOx elimination, especially when SO3 exists.

scholarly journals Ferrierite and Its Delaminated and Silica-Intercalated Forms Modified with Copper as Effective Catalysts for NH3-SCR Process

Catalysts ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 734 ◽  
Author(s):  
Aneta Święs ◽  
Andrzej Kowalczyk ◽  
Małgorzata Rutkowska ◽  
Urbano Díaz ◽  
Antonio E. Palomares ◽  
...  
Keyword(s):  
Low Temperature ◽  
Ammonia Oxidation ◽  
Catalytic Reduction ◽  
Surface Acidity ◽  
Side Reaction ◽  
Copper Species ◽  
Nh3 Scr ◽  
Scr Catalysts ◽  
Catalytically Active ◽  
Fast Scr

The main goal of the study was the development of effective catalysts for the low-temperature selective catalytic reduction of NO with ammonia (NH3-SCR), based on ferrierite (FER) and its delaminated (ITQ-6) and silica-intercalated (ITQ-36) forms modified with copper. The copper exchange zeolitic samples, with the intended framework Si/Al ratio of 30 and 50, were synthetized and characterized with respect to their chemical composition (ICP-OES), structure (XRD), texture (low-temperature N2 adsorption), form and aggregation of deposited copper species (UV-vis-DRS), surface acidity (NH3-TPD) and reducibility (H2-TPR). The samples of the Cu-ITQ-6 and Cu-ITQ-36 series were found to be significantly more active NH3-SCR catalysts compared to Cu-FER. The activity of these catalysts in low-temperature NH3-SCR was assigned to the significant contribution of highly dispersed copper species (monomeric cations and small oligomeric species) catalytically active in the oxidation of NO to NO2, which is necessary for fast-SCR. The zeolitic catalysts, with the higher framework alumina content, were more effective in high-temperature NH3-SCR due to their limited catalytic activity in the side reaction of ammonia oxidation.

The impact of light and heavy hydrocarbons on the NH3-SCR activity of commercial Cu- and Fe-zeolite catalysts

2019 ◽  
Vol 320 ◽  
pp. 100-111 ◽  
Author(s):  
Tommaso Selleri ◽  
Isabella Nova ◽  
Enrico Tronconi ◽  
Volker Schmeisser ◽  
Simone Seher
Keyword(s):  
Zeolite Catalysts ◽  
Heavy Hydrocarbons ◽  
Nh3 Scr ◽  
The Impact

scholarly journals Spherical Al-MCM-41 Doped with Copper by Modified TIE Method as Effective Catalyst for Low-Temperature NH3-SCR

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1807
Author(s):  
Aleksandra Jankowska ◽  
Andrzej Kowalczyk ◽  
Małgorzata Rutkowska ◽  
Marek Michalik ◽  
Lucjan Chmielarz
Keyword(s):  
Low Temperature ◽  
Ion Exchange ◽  
Ammonia Oxidation ◽  
Surface Acidity ◽  
Ammonia Solution ◽  
Exchange Method ◽  
Copper Species ◽  
Nh3 Scr ◽  
Side Process ◽  
Mcm 41

Aluminum containing silica spherical MCM-41 was synthesized and modified with copper by the template ion-exchange method (TIE) and its modified version, including treatment of the samples with ammonia solution directly after template ion-exchange (TIE-NH3). The obtained samples were characterized with respect to their chemical composition (ICP-OES), structure (XRD), texture (low temperature N2 sorption), morphology (SEM-EDS), form and aggregation of deposited copper species (UV-vis DRS), reducibility of copper species (H2-TPR), and surface acidity (NH3-TPD). The deposition of copper by the TIE-NH3 method resulted in much better dispersion of this metal on the MCM-41 surface comparing to copper introduced by TIE method. It was shown that such highly dispersed copper species, mainly monomeric Cu2+ cations, deposited on aluminum containing silica spheres of MCM-41, are significantly more catalytically effective in the NH3-SCR process than analogous catalysts containing aggregated copper oxide species. The catalysts obtained by the TIE-NH3 method effectively operated in much broader temperature and were less active in the side process of direct ammonia oxidation by oxygen.

scholarly journals Catalytic Performances of Cu/MCM-22 Zeolites with Different Cu Loadings in NH3-SCR

Nanomaterials ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 2170
Author(s):  
Jialing Chen ◽  
Gang Peng ◽  
Tingyu Liang ◽  
Wenbo Zhang ◽  
Wei Zheng ◽  
...  
Keyword(s):  
Incipient Wetness Impregnation ◽  
Impregnation Method ◽  
Hydrothermal Aging ◽  
Copper Species ◽  
Cu Content ◽  
Nh3 Scr ◽  
Water Vapor Atmosphere ◽  
Pore Blockage ◽  
Temperature Window ◽  
Catalytic Performances

The NH3-SCR activities and hydrothermal stabilities of five xCu/MCM-22 zeolites with different Cu loadings (x = 2–10 wt%) prepared by incipient wetness impregnation method were systematically investigated. The physicochemical properties of xCu/MCM-22 zeolites were analyzed by XRD, nitrogen physisorption, ICP-AES, SEM, NH3-TPD, UV-vis, H2-TPR and XPS experiments. The Cu species existing in xCu/MCM-22 are mainly isolated Cu2+, CuOx and unreducible copper species. The concentrations of both isolated Cu2+ and CuOx species in xCu/MCM-22 increase with Cu contents, but the increment of CuOx species is more distinct, especially in high Cu loadings (>4 wt%). NH3-SCR experimental results demonstrated that the activity of xCu/MCM-22 is sensitive to Cu content at low Cu loadings (≤4 wt%). When the Cu loading exceeds 4 wt%, the NH3-SCR activity of xCu/MCM-22 is irrelevant to Cu content due to the severe pore blockage effects caused by aggregated CuOx species. Among the five xCu/MCM-22 zeolites, 4Cu/MCM-22 with moderate Cu content has the best NH3-SCR performance, which displays higher than 80% NOx conversions in a wide temperature window (160–430 °C). Furthermore, the hydrothermal aging experiments (xCu/MCM-22 was treated at 750 °C for 10 h under 10% water vapor atmosphere) illustrated that all the xCu/MCM-22 zeolites exhibit high hydrothermal stability in NH3-SCR reactions.

scholarly journals N2O Formation during NH3-SCR over Different Zeolite Frameworks: Effect of Framework Structure, Copper Species, and Water

2021 ◽  
Author(s):  
Joonsoo Han ◽  
Aiyong Wang ◽  
Ghodsieh Isapour ◽  
Hanna Härelind ◽  
Magnus Skoglundh ◽  
...  
Keyword(s):  
Framework Structure ◽  
N2o Formation ◽  
Copper Species ◽  
Nh3 Scr

Different copper species as active sites for NH3-SCR reaction over Cu-SAPO-34 catalyst and reaction pathways: A periodic DFT study

2018 ◽  
Vol 266 ◽  
pp. 223-231 ◽  
Author(s):  
Guangpeng Yang ◽  
Jingyu Ran ◽  
Xuesen Du ◽  
Xiangmin Wang ◽  
Yanrong Chen ◽  
...  
Keyword(s):  
Active Sites ◽  
Dft Study ◽  
Reaction Pathways ◽  
Copper Species ◽  
Nh3 Scr ◽  
Periodic Dft
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