Mesoporous silicas of MCM-41 type modified with iron species by template ion-exchange method as catalysts for the high-temperature NH3-SCR process - role of iron species aggregation, silica morphology and associated reactions

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.

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

Canadian Journal of Chemistry ◽

10.1139/cjc-2019-0462 ◽

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.

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

Chemistry of Materials ◽

10.1021/cm970334w ◽

1997 ◽

Vol 9 (12) ◽

pp. 2679-2681 ◽

Cited By ~ 89

Author(s):

Maki Yonemitsu ◽

Yasuhiro Tanaka ◽

Masakazu Iwamoto

Keyword(s):

Ion Exchange ◽

Metal Ion ◽

Exchange Method ◽

Ion Exchange Method ◽

Mcm 41

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The Role of Ion Exchange Method of Na-ZSM-5 Zeolite and Influence Hydrogenation Components on Properties and Activity of Dewaxing Catalysts

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19920969 ◽

1992 ◽

Vol 57 (5) ◽

pp. 969-977 ◽

Cited By ~ 1

Author(s):

Jolanta R. Grzechowiak ◽

Aleksandra Masalska ◽

Tadeusz Romotowski ◽

Jolanta Komorek

Keyword(s):

Low Temperature ◽

Ion Exchange ◽

Flow Reactor ◽

Nitrate Solution ◽

Diesel Oil ◽

Ni Catalysts ◽

Exchange Method ◽

Oil Fraction ◽

Ion Exchange Method

Hydrocracking of n-hexane and diesel oil fraction over presulfided NiMo, Mo and Ni catalysts has been carried out using a high pressure flow reactor system. The ion-exchanged form of ZSM-5 extrudates (50% alumina binder) was loaded with 2-20 wt.% of metals. The results indicate that, using Ni/H-ZSM-5 zeolite obtained by incorporation of nickel by ion exchange treatment of NH4-ZSM-5 from nickel nitrate solution, it is possible to obtain sufficiently active catalysts for low-temperature hydrocracking process. The catalysts containing Ni-ZSM-5 zeolites (Ni/H-ZSM-5 or Ni/Na-ZSM-5) were superior to catalyst prepared by using P/H-ZSM-5. It was found that nickel was an essential hydrogenation components of low temperature hydrocracking catalysts.

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MCM-41 modified with transition metals by template ion-exchange method as catalysts for selective catalytic oxidation of ammonia to dinitrogen

Microporous and Mesoporous Materials ◽

10.1016/j.micromeso.2016.11.002 ◽

2017 ◽

Vol 240 ◽

pp. 9-21 ◽

Cited By ~ 23

Author(s):

Andrzej Kowalczyk ◽

Aleksandra Borcuch ◽

Marek Michalik ◽

Małgorzata Rutkowska ◽

Barbara Gil ◽

...

Keyword(s):

Ion Exchange ◽

Transition Metals ◽

Catalytic Oxidation ◽

Exchange Method ◽

Selective Catalytic Oxidation ◽

Ion Exchange Method ◽

Mcm 41 ◽

Oxidation Of Ammonia

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

Molecules ◽

10.3390/molecules26061807 ◽

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.

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