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 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.

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

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4885
Author(s):  
Aneta Święs ◽  
Małgorzata Rutkowska ◽  
Andrzej Kowalczyk ◽  
Urbano Díaz ◽  
Antonio E. Palomares ◽  
...  
Keyword(s):  
Copper Oxide ◽  
Ammonia Oxidation ◽  
Catalytic Reduction ◽  
Surface Acidity ◽  
Selective Reduction ◽  
Exchange Method ◽  
Copper Species ◽  
Selective Catalytic Oxidation ◽  
Catalytically Active ◽  
Copper Cations

Ferrierites and their delaminated forms (ITQ-6), containing aluminum or titanium in the zeolite framework, were synthetized and modified with copper by an ion-exchange method. The obtained samples were characterized with respect to their chemical composition (ICP-OES), structure (XRD, UV-Vis DRS), textural parameters (N2-sorption), surface acidity (NH3-TPD), form and reducibility of deposited copper species (UV-Vis DRS and H2-TPR). Ferrierites and delaminated ITQ-6 zeolites modified with copper were studied as catalysts for the selective catalytic oxidation of ammonia to dinitrogen (NH3-SCO). It was shown that aggregated copper oxide species, which were preferentially formed on Ti-zeolites, were catalytically active in direct low-temperature ammonia oxidation to NO, while copper introduced into Al-zeolites was present mainly in the form of monomeric copper cations catalytically active in selective reduction of NO by ammonia to dinitrogen. It was postulated that ammonia oxidation in the presence of the studied catalysts proceeds according to the internal-selective catalytic reduction mechanism (i-SCR) and therefore the suitable ratio between aggregated copper oxide species and monomeric copper cations is necessary to obtain active and selective catalysts for the NH3-SCO process. Cu/Al-ITQ-6 presented the best catalytic properties possibly due to the most optimal ratio of these copper species.

scholarly journals Catalytic Performance of Spherical MCM-41 Modified with Copper and Iron as Catalysts of NH3-SCR Process

Molecules ◽  
2020 ◽  
Vol 25 (23) ◽  
pp. 5651
Author(s):  
Aleksandra Jankowska ◽  
Agata Chłopek ◽  
Andrzej Kowalczyk ◽  
Małgorzata Rutkowska ◽  
Marek Michalik ◽  
...  
Keyword(s):  
Ammonia Oxidation ◽  
Surface Acidity ◽  
Catalytic Performance ◽  
Emission Spectrometry ◽  
High Catalytic Activity ◽  
Reaction Products ◽  
Nh3 Scr ◽  
Vis Spectroscopy ◽  
Temperature Programmed ◽  
Mcm 41

Spherical MCM-41 with various copper and iron loadings was prepared by surfactant directed co-condensation method. The obtained samples were characterized with respect to their structure (X-ray diffraction, XRD), texture (N2 sorption), morphology (scanning electron microscopy, SEM), chemical composition (inductively coupled plasma optical emission spectrometry, ICP-OES), surface acidity (temperature programmed desorption of ammonia, NH3-TPD), form, and aggregation of iron and copper species (diffuse reflectance UV-Vis spectroscopy, UV-Vis DRS) as well as their reducibility (temperature programmed reduction with hydrogen, H2-TPR). The spherical MCM-41 samples modified with transition metals were tested as catalysts of selective catalytic reduction of NO with ammonia (NH3-SCR). Copper containing catalysts presented high catalytic activity at low-temperature NH3-SCR with a very high selectivity to nitrogen, which is desired reaction products. Similar results were obtained for iron containing catalysts, however in this case the loadings and forms of iron incorporated into silica samples very strongly influenced catalytic performance of the studied samples. The efficiency of the NH3-SCR process at higher temperatures was significantly limited by the side reaction of direct ammonia oxidation. The reactivity of ammonia molecules chemisorbed on the catalysts surface in NO reduction (NH3-SCR) and their selective oxidation (NH3-SCO) was verified by temperature-programmed surface reactions.

Effective catalysts for the low-temperature NH3-SCR process based on MCM-41 modified with copper by template ion-exchange (TIE) method

2018 ◽  
Vol 237 ◽  
pp. 927-937 ◽  
Author(s):  
Andrzej Kowalczyk ◽  
Aneta Święs ◽  
Barbara Gil ◽  
Małgorzata Rutkowska ◽  
Zofia Piwowarska ◽  
...  
Keyword(s):  
Low Temperature ◽  
Ion Exchange ◽  
Nh3 Scr ◽  
Mcm 41

Enhanced catalytic performance in low-temperature NH3-SCR process of spherical MCM-41 modified with Cu by template ion-exchange and ammonia treatment

2021 ◽  
Vol 315 ◽  
pp. 110920
Author(s):  
Aleksandra Jankowska ◽  
Agata Chłopek ◽  
Andrzej Kowalczyk ◽  
Małgorzata Rutkowska ◽  
Włodzimierz Mozgawa ◽  
...  
Keyword(s):  
Low Temperature ◽  
Ion Exchange ◽  
Catalytic Performance ◽  
Ammonia Treatment ◽  
Nh3 Scr ◽  
Mcm 41

The role of various iron species in Fe-β catalysts with low iron loadings for NH3-SCR

2014 ◽  
Vol 4 (5) ◽  
pp. 1350-1356 ◽  
Author(s):  
Haiyan Liu ◽  
Jun Wang ◽  
Tie Yu ◽  
Shikuan Fan ◽  
Meiqing Shen
Keyword(s):  
Ion Exchange ◽  
Iron Species ◽  
Exchange Method ◽  
Nh3 Scr ◽  
Ion Exchange Method

A series of Fe-β catalysts, containing 0.17–0.52 wt% Fe, were prepared by a liquid ion-exchange method to study the influence of various iron species on NH3-SCR activity.

scholarly journals Effect of Ion-Exchange Sequences on Catalytic Performance of Cerium-Modified Cu-SSZ-13 Catalysts for NH3-SCR

Catalysts ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 997
Author(s):  
Yan Wang ◽  
Zhaoqiang Li ◽  
Zhiyong Ding ◽  
Na Kang ◽  
Rongrong Fan ◽  
...  
Keyword(s):  
Ion Exchange ◽  
Copper Ions ◽  
Reduction Process ◽  
Catalytic Performance ◽  
Adsorbed Species ◽  
Exchange Method ◽  
Coordination Environment ◽  
Nh3 Scr ◽  
Nox Conversion ◽  
Acidic Sites

Cerium-modified Cu-SSZ-13 catalysts were prepared by an aqueous ion-exchange method, and Ce and Cu were incorporated through different ion-exchange sequences. The results of NH3-SCR activity evaluations displayed that Cu1(CeCu)2 catalyst presented excellent catalytic activity, and over 90% NOx conversion was obtained across the temperature range of 200–500 °C. The characterization results showed that the ion-exchange sequence of Cu and Ce species influenced the crystallinity of the zeolites and the coordination of Al. A small amount of Ce could participate in the reduction process and change the location and coordination environment of copper ions. Furthermore, Ce-modified Cu-SSZ-13 catalysts possessed more acidic sites due to their containing replacement of Ce and movement of Cu in the preparation process. The cooperation of strong redox abilities and NH3 storage capacity led to the increase of active adsorbed species adsorption and resulted in better activity of Cu1(CeCu)2.

Investigation on the stability of copper modification of SAPO-34 catalysts in NH3-SCR reaction after hydrothermal aging

2020 ◽  
Vol 98 (5) ◽  
pp. 236-243
Author(s):  
Xiaoxin Wu ◽  
Jiaxi Peng ◽  
Shaoming Yang ◽  
Wenyuan Xu
Keyword(s):  
Ion Exchange ◽  
Copper Oxide ◽  
Structural Stability ◽  
Solid State Nmr ◽  
Impregnation Method ◽  
Hydrothermal Aging ◽  
Exchange Method ◽  
Nh3 Scr ◽  
Ion Exchange Method ◽  
The Stability

The influence of hydrothermal aging on the structural stability of Cu-modified SAPO-34 prepared by ion-exchange and impregnation methods was studied. XRD, Ar adsorption at −196 °C, solid-state NMR, UV–vis, H2-TPR, and EPR were used to probe the structural properties of the catalysts. It was found that the precipitation of crystalline AlPO4 and SiO2, the appearance of mesopores, the migration of silicon to form siliceous islands, and the formation of copper oxide crystallites occurred in aged catalysts. Furthermore, more siliceous islands and copper oxide crystallites were present in the aged samples prepared by the impregnation method than in those prepared by the ion-exchange method. Therefore, the impregnated catalysts show a much poorer structural stability than the ion-exchanged catalysts, which leads to more serious deterioration in the NH3-SCR reaction after hydrothermal aging.

Metal Ion-Planted MCM-41. 1. Planting of Manganese(II) Ion into MCM-41 by a Newly Developed Template-Ion Exchange Method

1997 ◽  
Vol 9 (12) ◽  
pp. 2679-2681 ◽  
Author(s):  
Maki Yonemitsu ◽  
Yasuhiro Tanaka ◽  
Masakazu Iwamoto
Keyword(s):  
Ion Exchange ◽  
Metal Ion ◽  
Exchange Method ◽  
Ion Exchange Method ◽  
Mcm 41
Sign in / Sign up

Export Citation Format

Share Document