Europium(3+): An Efficient Luminescence Probe for the Si to Al Ratio and Silylation Effects in the Microporous−Mesoporous Zeogrid Materials

Tiseanu, Carmen; Kumke, Michael U.; Pârvulescu, Vasile I.; Geßner, André; Gagea, Bogdan C.; Martens, Johan A.

doi:10.1021/jp711337h

Cited by 9 publications

(9 citation statements)

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“…For instance, optical properties of zeolites, containing exchanged cations of different metals, have been extensively studied over the last decades. In part, photoluminescence (PL) properties of different zeolites, doped with metal cations such as Cu + , , Ag + , − Eu 2+ /Eu 3+ , , Tb 3+ , Yb 3+ , Er 3+ , Bi 3+ , , and Ga + were reported. The band gap of about 7 eV of the aluminosilicate zeolite framework is similar to that of α-quartz. − The exchanged cations cause new electronic states that can lie within the zeolite band gap region.…”

Section: Introductionmentioning

confidence: 99%

Photoluminescence Properties of Indium-Exchanged ZSM-5 Zeolite

Serykh

Rozhdestvenskaya

2015

J. Phys. Chem. C

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Optical properties (optical absorption and photoluminescence) of indium-exchanged ZSM-5 zeolite have been characterized. It has been found for the first time that reduced In-ZSM-5, containing low-valence In + exchanged cations, exhibits efficient ultraviolet and visible-light photoluminescence. The photoluminescence can be induced by the electronic excitation transitions A, B, and C similar to those either in indium halides or in indium-doped alkali halides. The ultraviolet photoluminescence is associated with isolated In + cations, while the visible-light photoluminescence is most probably due to radiative relaxation of In + oligomers or low-dimensional clusters. ■ INTRODUCTIONZeolites are often considered as host materials for different occluded guests, such as small nanoparticles, dyes, complexes, and ions. Zeolites are nanoporous crystalline aluminosilicates with cavity and channel structures. Their framework, which is constructed of SiO 4 and AlO 4 tetrahedra linked through oxygen atoms, can be considered as a large crystalline polyanion which contains either protons or metal cations for charge compensation. Due to unique highly ordered porous and channel structure of zeolites it can be possible to manage a spatial pattern of the guest species to tune their electronic and optical properties. Furthermore, the aluminum content in a zeolite framework defines concentration of charge-compensating cations and can strongly affect their valence state so that zeolites are capable of stabilizing exchanged metal cations in a certain valence state. For instance, optical properties of zeolites, containing exchanged cations of different metals, have been extensively studied over the last decades. In part, photoluminescence (PL) properties of different zeolites, doped with metal cations such as Cu + , 1,2 Ag + , 3−5 Eu 2+ /Eu 3+ , 6,7 Tb 3+ , 8 Yb 3+ , 9 Er 3+ , 10 Bi 3+ , 11,12 and Ga +13 were reported. The band gap of about 7 eV of the aluminosilicate zeolite framework is similar to that of α-quartz. 14−16 The exchanged cations cause new electronic states that can lie within the zeolite band gap region. These cations can interact with each other to form cation pairs or clusters depending on their nature and distance between them.Indium-exchanged ZSM-5 zeolite has attracted much attention from researchers in the last few years since it is considered as a most promising catalyst for NOx reduction by hydrocarbons. 17,18 Indium is usually introduced into zeolites by the reductive solid state ion exchange. For this the hydrogen form of a zeolite is either mixed with In 2 O 3 powder or impregnated with an aqueous solution of indium nitrate with subsequent drying and calcination. After that, the samples are subjected to high-temperature reduction in hydrogen. As a result, the reduced indium species migrate from the external surface into zeolite channels and interact with acidic protons to form exchanged In + cations. 19 Until now optical properties of indium-exchanged zeolites have not been reported in the literature. However, ...

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Section: Introductionmentioning

confidence: 99%

Photoluminescence Properties of Indium-Exchanged ZSM-5 Zeolite

Serykh

Rozhdestvenskaya

2015

J. Phys. Chem. C

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“…A fine-tuning of the photoluminescence (PL) properties (spectral range, lifetime, and quantum efficiency) can thus be envisaged through combining the organic and inorganic constituents with the lanthanide ions. Thus, PL properties of lanthanide based hybrid materials are covering a wide range of PL lifetimes (from nano- to milliseconds) and emission wavelengths, from VIS (Eu 3+ , Tb 3+ ) to NIR (Nd 3+ , Er 3+ , Yb 3+ Ho 3+ , Pr 3+ , Sm 3+ , or Tm 3+ ). − Silicon alkoxides and derived organically modified supports are generally the main precursors used for lanthanide-containing materials. − Doping of the mesoporous silica with lanthanide complexes, in which only weak physical interactions (hydrogen bonding, van der Waals force, or weak static effect) exist between the support and the immobilized lanthanide complexes, causes several drawbacks, such as clustering of the emitting centers, inhomogeneous dispersion of both components, and leaching of the lanthanide’s complexes that are not anchored to the silica matrix (class I materials) . A more promising approach is to use a homogeneous dispersion of the lanthanide cations within the hybrid materials as a result of the hydrolysis and polycondensation of the lanthanides complexes with ligands bearing hydrolyzable Si(OR) 3 groups.…”

Section: Introductionmentioning

confidence: 99%

Effects of Support and Ligand on the Photoluminescence Properties of Siliceous Grafted Europium Complexes

et al. 2009

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Europium ions were introduced in SiO 2 and MCM-41 via two different pathways: (1) grafting the europium complexes with two alkoxide structures, 3-(2-imidazolin-1-yl)-propyl-triethoxysilane (IPTES) and aminopropyltrimethoxysilane (APTMS), and (2) functionalization of the SiO 2 support with silicon 4-carboxylbutyltriethoxide followed by subsequent addition of the europium ions. The new materials were characterized using nitrogen adsorption isotherms at -196 °C, thermogravimetric analysis, scanning electron microscopy, transmission electron microscopy, powder X-ray diffraction, Fourier transform infrared, NMR, DR-UV-vis, steady-state emission and excitation, and time-resolved photoluminescence spectroscopy. Spectral changes found in the time-resolved photoluminscence spectra strongly point to the distribution of europium ions on a range of environments in both SiO 2 and MCM-41 supports. The average europium photoluminescence lifetimes decrease within the order: Eu 3+ -IPTES/SiO 2 (550 µs) > Eu 3+ -APTMS/ SiO 2 (425 µs) > Eu 3+ -APTMS/MCM-41 (370 µs) > Eu 3+ -IPTES/MCM-41 (320 µs) > Eu 3+ -CABES/SiO 2 (240 µs). The photoluminescence quantum efficiency has the largest value, of 22%, for Eu 3+ -IPTES/SiO 2 , while the most reduced value, of 9%, was measured for Eu 3+ -CABES/SiO 2 .

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“…Zeotile-1 and zeogrids have been used as support for photoluminescent europium and terbium. Discrete types of luminescence were observed, in contrast to zeolites in which a heterogenous distribution of luminescences were observed (Tiseanu et al, 2006;Tiseanu et al, 2008c;Tiseanu et al, 2008a;Tiseanu et al, 2008b;Tiseanu et al, 2009). The potential of zeogrid and zeotiles in catalysis has been evaluated in hydroisomerization and hydrocracking, catalytic cracking, alkylation, and epoxidation reactions.…”

Section: Zeogrids and Zeotilesmentioning

confidence: 99%

Hierarchical COK-X Materials for Applications in Catalysis and Adsorptive Separation and Controlled Release

et al. 2022

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Over the years, COK has developed a family of silicate materials and metal–organic framework hybrids with hierarchical porosity and functionality, coined zeogrids, zeotiles, and COK-x (stemming from the Flemish name of the laboratory “Centrum voor Oppervlaktechemie en Katalyse”). Several of these materials have unique features relevant to heterogeneous catalysis, molecular separation, and controlled release and found applications in the field of green chemistry, environmental protection, and pharmaceutical formulation. Discovery of a new material typically occurs by serendipity, but the research was always guided by hypothesis. This review provides insight in the process of tuning initial research hypotheses to match material properties to specific applications. This review describes the synthesis, structure, properties, and applications of 12 different materials. Some have simple synthesis protocols, facilitating upscaling and reproduction and rendering them attractive also in this respect.

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Europium(3+): An Efficient Luminescence Probe for the Si to Al Ratio and Silylation Effects in the Microporous−Mesoporous Zeogrid Materials

Cited by 9 publications

References 84 publications

Photoluminescence Properties of Indium-Exchanged ZSM-5 Zeolite

Photoluminescence Properties of Indium-Exchanged ZSM-5 Zeolite

Effects of Support and Ligand on the Photoluminescence Properties of Siliceous Grafted Europium Complexes

Hierarchical COK-X Materials for Applications in Catalysis and Adsorptive Separation and Controlled Release

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