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O'Nolan D, Zhao H, Chen Z, Grenier A, Beauvais ML, Newton MA, Nenoff TM, Chupas PJ, Chapman KW. A multimodal analytical toolkit to resolve correlated reaction pathways: the case of nanoparticle formation in zeolites. Chem Sci 2021; 12:13836-13847. [PMID: 34760169 PMCID: PMC8549813 DOI: 10.1039/d1sc04232g] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Accepted: 09/13/2021] [Indexed: 12/18/2022] Open
Abstract
Unraveling the complex, competing pathways that can govern reactions in multicomponent systems is an experimental and technical challenge. We outline and apply a novel analytical toolkit that fully leverages the synchronicity of multimodal experiments to deconvolute causal from correlative relationships and resolve structural and chemical changes in complex materials. Here, simultaneous multimodal measurements combined diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and angular dispersive X-ray scattering suitable for pair distribution function (PDF), X-ray diffraction (XRD) and small angle X-ray scattering (SAXS) analyses. The multimodal experimental data was interpreted via multi-level analysis; conventional analyses of each data series were integrated through meta-analysis involving non-negative matrix factorization (NMF) as a dimensional reduction algorithm and correlation analysis. We apply this toolkit to build a cohesive mechanistic picture of the pathways governing silver nanoparticle formation in zeolite A (LTA), which is key to designing catalytic and separations-based applications. For this Ag-LTA system, the mechanisms of zeolite dehydration, framework flexing, ion reduction, and cluster and nanoparticle formation and transport through the zeolite are elucidated. We note that the advanced analytical approach outline here can be applied generally to multimodal experiments, to take full advantage of the efficiencies and self-consistencies in understanding complex materials and go beyond what can be achieved by conventional approaches to data analysis. Multimodal in situ experimental data probing a complex reaction have been integrated via a multi-level analysis involving non-negative matrix factorization and correlation analysis. This strategy can be applied generally to multimodal experiments.![]()
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Affiliation(s)
- Daniel O'Nolan
- Department of Chemistry, Stony Brook University 100 Nicolls Rd, Stony Brook New York 11790 USA
| | - Haiyan Zhao
- X-ray Science Division, Advanced Photon Source, Argonne National Laboratory Lemont Illinois 60439 USA
| | - Zhihengyu Chen
- Department of Chemistry, Stony Brook University 100 Nicolls Rd, Stony Brook New York 11790 USA
| | - Antonin Grenier
- Department of Chemistry, Stony Brook University 100 Nicolls Rd, Stony Brook New York 11790 USA
| | - Michelle L Beauvais
- Department of Chemistry, Stony Brook University 100 Nicolls Rd, Stony Brook New York 11790 USA
| | - Mark A Newton
- Department of Chemistry and Applied Biosciences, ETH Zürich Zürich Switzerland
| | - Tina M Nenoff
- Sandia National Laboratories, Materials Chemicals and Physics Center Albuquerque New Mexico 87185 USA
| | - Peter J Chupas
- Department of Chemistry, Stony Brook University 100 Nicolls Rd, Stony Brook New York 11790 USA .,X-ray Science Division, Advanced Photon Source, Argonne National Laboratory Lemont Illinois 60439 USA.,Associated Universities Inc 16th Street NW, Suite 730 Washington DC 20036 USA
| | - Karena W Chapman
- Department of Chemistry, Stony Brook University 100 Nicolls Rd, Stony Brook New York 11790 USA .,X-ray Science Division, Advanced Photon Source, Argonne National Laboratory Lemont Illinois 60439 USA
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Calzaferri G. Entropy in multiple equilibria, compounds with different sites. Phys Chem Chem Phys 2018; 20:29070-29084. [PMID: 30452040 DOI: 10.1039/c8cp04145h] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The influence of entropy in multiple chemical equilibria is investigated for systems with different types of sites for the condition that the binding enthalpy of the species is the same within each type of sites and independent of those species that are already bonded. This allows splitting of the free reaction enthalpy into the particle distribution term and all other contributions for each type of sites separately and, hence, to evaluate this entropy contribution to the free reaction enthalpy. The situations for which this applies can be chemically very different, e.g. acid base, ligand exchange, isomerisation, conformational change, rearrangement of a ligand, ion exchange, adsorption of a species on the surface of a particle or a dendrimer, insertion of charged or neutral species into the cavities of a microporous or mesoporous host. We provide physical insight by discussing Xrc1{n1ABn2}Xrc2 systems. The number of coordination sites A and B are n1 and n2, respectively. The indices rc1 = 1, 2,…,n1 and rc2 = 1, 2,…,n2 count the number of X bonded to sites A and sites B, respectively. An important result is that the large number of equilibrium constants needed to describe those situations can be expressed as a function of two constants only. This allows studying systems quantitatively by experimental and theoretical means which otherwise might be difficult to handle. It has also implication for theoretical studies in the sense that it is sufficient to model only two reactions instead of many in order to describe a system. The results remain valid for systems with more than two types of different sites. The description of the entropy driven development of the fractional equilibrium coverage of the sites provides a new tool for understanding adsorption and ion exchange isotherms. The fractional equilibrium coverage of the sites can be described as a linear combination of individual Langmuir isotherms despite of the fact that such a linear combination has never the shape of the original Langmuir isotherm. This is remarkable and very useful. It provides us with new tools for describing and testing isotherms based on well defined, transparent physical ideas. Explicit solution for systems with 2, 3, 4, 5, 6, and 12 coordination sites are reported. Applications to a system with 12 coordination sites serve to illustrate information that can be obtained for complex situations.
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Affiliation(s)
- Gion Calzaferri
- Department of Chemistry and Biochemistry, Freiestrasse 3, 3012 Bern, Switzerland.
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Coutiño-Gonzalez E, Baekelant W, Steele JA, Kim CW, Roeffaers MBJ, Hofkens J. Silver Clusters in Zeolites: From Self-Assembly to Ground-Breaking Luminescent Properties. Acc Chem Res 2017; 50:2353-2361. [PMID: 28862837 DOI: 10.1021/acs.accounts.7b00295] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Interest for functional silver clusters (Ag-CLs) has rapidly grown over years due to large advances in the field of nanoscale fabrication and materials science. The continuous development of strategies to fabricate small-scale silver clusters, together with their interesting physicochemical properties (molecule-like discrete energy levels, for example), make them very attractive for a wide variety of applied research fields, from biotechnology and the environmental sciences to fundamental chemistry and physics. Apart from useful catalytic properties, silver clusters (Agn, n < 10) were recently shown to also exhibit exceptional optical properties. The optical properties and performance of Ag-CLs offer strong potential for their integration into appealing micro(nano)-optoelectronic devices. To date, however, the rational design and directed synthesis of Ag-CLs with specific functionalities has remained elusive. The inability for rational design stems mainly from a lack of understanding of their novel atomic-scale phenomena. This is because accurately studying silver cluster systems at such a scale is hindered by the perturbations introduced during exposure to various experimental probes. For instance, silver possesses a strong tendency to cluster and form ever-larger Ag aggregates while probed with high-energy electron beams and X-ray irradiation. As well, there exists a need to provide a stabilizing environment for which Agnδ+ clusters can persist, setting up a complex interacting guest-host system, as isolated silver clusters are confined within a suitable hosting medium. Fundamental research into Agnδ+ formation mechanisms and their important optical properties is paramount to establishing truly informed synthesis protocols. Over recent years, we have developed several protocols for the ship-in-a-bottle synthesis of highly luminescent Ag-CLs within the microporous interiors of zeolite frameworks. This approach has yielded materials displaying a wide variety of optical properties, offering a spectrum of possible applications, from nano(micro)photonic devices to smart luminescent labels and sensors. The versatility of the Ag-zeolite multicomponent system is directly related to the intrinsic and complex tunability of the system as a whole. There are several key zeolite parameters that confer properties to the clusters, namely, the framework Si/Al ratio, choice of counterbalancing ions, silver loading, and zeolite topology, and cannot be overlooked. This Account is intended to shed light on the current state-of-the-art of luminescent Ag-CLs confined in zeolitic matrices, emphasizing the use of combinatorial approaches to overcome problems associated with the correct characterization and correlation of their structural, electronic, and photoluminescence properties, all to establish the important design principles for developing functional silver-zeolite-based materials. Additionally, examples of emerging applications and future perspectives for functional luminescent Ag-zeolite materials are addressed in this Account.
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Affiliation(s)
- Eduardo Coutiño-Gonzalez
- Chem&Tech - Molecular Imaging and Photonics, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
- CONACYT
- Centro de Investigación y Desarrollo Tecnológico en
Electroquímica, Parque Industrial Querétaro, Sanfandila s/n, Pedro Escobedo, 76703 Querétaro, Mexico
| | - Wouter Baekelant
- Chem&Tech - Molecular Imaging and Photonics, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Julian A. Steele
- Chem&Tech - Centre for Surface Chemistry and Catalysis, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Cheol Woong Kim
- Chem&Tech - Molecular Imaging and Photonics, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Maarten B. J. Roeffaers
- Chem&Tech - Centre for Surface Chemistry and Catalysis, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Johan Hofkens
- Chem&Tech - Molecular Imaging and Photonics, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
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Ultrafast coherence transfer in DNA-templated silver nanoclusters. Nat Commun 2017; 8:15577. [PMID: 28548085 PMCID: PMC5493596 DOI: 10.1038/ncomms15577] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Accepted: 04/06/2017] [Indexed: 12/16/2022] Open
Abstract
DNA-templated silver nanoclusters of a few tens of atoms or less have come into prominence over the last several years due to very strong absorption and efficient emission. Applications in microscopy and sensing have already been realized, however little is known about the excited-state structure and dynamics in these clusters. Here we report on a multidimensional spectroscopy investigation of the energy-level structure and the early-time relaxation cascade, which eventually results in the population of an emitting state. We find that the ultrafast intramolecular relaxation is strongly coupled to a specific vibrational mode, resulting in the concerted transfer of population and coherence between excited states on a sub-100 fs timescale. DNA-templated silver nanoclusters possess desirable optical properties, but their excited state dynamics remain poorly understood. Here the authors show that intracluster relaxations in such clusters are strongly coupled to a vibrational mode, resulting in ultrafast concerted transfer of population and coherence between excited states.
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Calzaferri G. Entropy in multiple equilibria, theory and applications. Phys Chem Chem Phys 2017; 19:10611-10621. [DOI: 10.1039/c7cp00584a] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Entropy controls the dependence of the equilibrium constants in the synthesis of host–guest composites on the occupation rc for channels of different length.
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Affiliation(s)
- Gion Calzaferri
- Department of Chemistry and Biochemistry
- 3012 Bern
- Switzerland
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Nagendiran S, Chinnakkannu Karikal Chozhan, Alagar M, Hamerton I. Inorganic/Organic Hybrid Nanocomposites involving OMMT Clay and Cyanate ester—Siloxane-modified Epoxy Resin: Thermal, Dielectric and Morphological Properties. HIGH PERFORM POLYM 2007. [DOI: 10.1177/0954008307082151] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Inorganic—organic hybrid nanocomposites were prepared by the following steps: (1) homogeneous dispersion of various percentages (1 to 5% w/w) of organically modified montmorollonite clay in epoxy matrix resin; (2) the resulting homogeneous epoxy—clay hybrids were modified with 10 wt.% of hydroxyl-terminated polydiemthyl siloxane (HTPDMS) using γ -aminopropyltriethoxysilane ( γ APS) as coupling agent in the presence of dibutyltindilaurate catalyst; and (3) the siliconized epoxy—clay prepolymers were further modified separately with 10 wt% of three different cyanate ester monomers and cured with diaminodiphenylmethane. The chemical interactions between epoxy, clay, HTPDMS and cyanate ester were confirmed by Fourier transform infrared spectral analysis. The values obtained from differential scanning calorimetry and dynamic mechanical analysis showed that there was a significant loss of glass transition temperatures in the resulting hybrid epoxy nanocomposite systems compared with that of neat epoxy system. The inorganic clay mineral and the formation of thermally stable oxazolidinone structures and siloxane linkages during curing led to significant improvement in the thermal properties of the resulting nanocomposites. A decreasing trend was identified in the resulting nanocomposites from their values of dielectric constant and dielectric loss by the incorporation of clay, HTPDMS and cyanate ester in the epoxy resin. The intercalation/exfoliation structure was studied using X-ray diffraction analysis and the homogeneous/heterogeneous morphology was studied using scanning electron microscopy analysis in the resulting nanocomposites.
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Affiliation(s)
| | | | | | - Ion Hamerton
- Chemistry Division, School of Biomedical and Molecular Sciences, University of Surrey, Guildford, Surrey GU2 7XH, UK
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Lupinetti AJ, Strauss SH, Frenking G. Nonclassical Metal Carbonyls. PROGRESS IN INORGANIC CHEMISTRY 2007. [DOI: 10.1002/9780470166512.ch1] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Qu Z, Huang W, Cheng M, Bao X. Restructuring and Redispersion of Silver on SiO2 under Oxidizing/Reducing Atmospheres and Its Activity toward CO Oxidation. J Phys Chem B 2005; 109:15842-8. [PMID: 16853013 DOI: 10.1021/jp050152m] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The effects of oxygen-hydrogen pretreatments of nanosilver catalysts in cycle mode on the structure and particle size of silver particles, and subsequently the activity of the catalyst toward CO oxidation (or CO selective oxidation in the presence of H2), are reported in this paper. Ag/SiO2 catalyst with silver particle sizes of ca. 6 approximately 8 nm shows relatively high activity in the present reaction system. The adopting of a cycle of oxidation/reduction pretreatment has a marked influence on the activity of the catalyst. Oxygen pretreatment at 500 degrees C results in the formation of subsurface oxygen and activates the catalyst. As evidenced by in-situ XRD and TEM, the following H2 treatment at low temperatures (100 approximately 300 degrees C) causes surface faceting and redispersing of the silver particles without destroying the subsurface oxygen species. The subsequent in-situ FTIR and catalytic reaction results show that CO oxidation occurs at -75 degrees C and complete CO conversion can be obtained at 40 degrees C over such a nanosilver catalyst pretreated with oxygen at 500 degrees C followed by H2 at 100 degrees C. However, prolonged hydrogen treatment at high temperatures (>300 degrees C) after oxygen pretreatment at 500 degrees C induces the aggregation of silver particles and also depletes so much subsurface oxygen species that the pathway of CO oxidation by the subsurface oxygen species is inhibited. Meanwhile, the ability of the catalyst to adsorb reactants is greatly depressed, resulting in a 20 approximately 30% decrease in the activity toward CO oxidation. However, the activity of the catalyst pretreated with oxygen at 500 degrees C followed by hydrogen treatment at high temperatures (>300 degrees C) is still higher than that directly pretreated with H2. This kind of catalytic behavior of silver catalyst is associated with physical changes in the silver crystallites because of surface restructuring and crystallite redispersion during the course of oxygen-hydrogen pretreatment steps.
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Affiliation(s)
- Zhenping Qu
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, P.O. Box 110, Dalian 116023, China
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CO adsorption and correlation between CO surface coverage and activity/selectivity of preferential CO oxidation over supported Ag catalyst: an in situ FTIR study. Catal Letters 2005. [DOI: 10.1007/s10562-004-3742-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Wang P, Yang S, Kondo JN, Domen K, Baba T. Characterization of Ag+-Exchanged Zeolite A with H2and CO Adsorption by FTIR. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2004. [DOI: 10.1246/bcsj.77.1627] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Ju WS, Matsuoka M, Iino K, Yamashita H, Anpo M. The Local Structures of Silver(I) Ion Catalysts Anchored within Zeolite Cavities and Their Photocatalytic Reactivities for the Elimination of N2O into N2 and O2. J Phys Chem B 2004. [DOI: 10.1021/jp0302919] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Woo-Sung Ju
- Department of Applied Chemistry, Graduate School of Engineering, Osaka Prefecture University, 1-1 Gakuen-cho, Sakai, Osaka 599-8531, Japan
| | - Masaya Matsuoka
- Department of Applied Chemistry, Graduate School of Engineering, Osaka Prefecture University, 1-1 Gakuen-cho, Sakai, Osaka 599-8531, Japan
| | - Kiyoshi Iino
- Department of Applied Chemistry, Graduate School of Engineering, Osaka Prefecture University, 1-1 Gakuen-cho, Sakai, Osaka 599-8531, Japan
| | - Hiromi Yamashita
- Department of Applied Chemistry, Graduate School of Engineering, Osaka Prefecture University, 1-1 Gakuen-cho, Sakai, Osaka 599-8531, Japan
| | - Masakazu Anpo
- Department of Applied Chemistry, Graduate School of Engineering, Osaka Prefecture University, 1-1 Gakuen-cho, Sakai, Osaka 599-8531, Japan
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Calzaferri G, Leiggener C, Glaus S, Schürch D, Kuge K. The electronic structure of Cu+, Ag+, and Au+ zeolites. Chem Soc Rev 2003; 32:29-37. [PMID: 12596543 DOI: 10.1039/b108571a] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A variety of procedures have been used to prepare d10-zeolite materials. The electronic structure of these materials can be regarded to a first approximation as a superposition of the framework, of the charge compensating ions, of solvent molecules and of guest species. Zeolite oxygen to d10-ion charge transfer transitions dominate the electronic spectra if the ions coordinate to the zeolite oxygens. Specific coordination sites can influence the energy and the intensity of these transitions remarkably. Intra guest transitions dominate in quantum dot materials, as discussed in detail for luminescent Ag2S zeolite A. The zeolite is not needed for the photocatalytic water oxidation on Ag+/AgCl photo anodes with visible light. It can, however, be used to increase the active surface area substantially.
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Affiliation(s)
- Gion Calzaferri
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, CH-3000 Bern 9, Switzerland
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Characterization of oxide surfaces and zeolites by carbon monoxide as an IR probe molecule. ADVANCES IN CATALYSIS 2002. [DOI: 10.1016/s0360-0564(02)47008-3] [Citation(s) in RCA: 353] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
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Bordiga S, Turnes Palomino G, Arduino D, Lamberti C, Zecchina A, Otero Areán C. Well defined carbonyl complexes in Ag+- and Cu+-exchanged ZSM-5 zeolite: a comparison with homogeneous counterparts. ACTA ACUST UNITED AC 1999. [DOI: 10.1016/s1381-1169(99)00082-5] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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16
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Hennessy B, Megelski S, Marcolli C, Shklover V, Bärlocher C, Calzaferri G. Characterization of Methyl Viologen in the Channels of Zeolite L. J Phys Chem B 1999. [DOI: 10.1021/jp984573y] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Hadjiivanov K, Knözinger H. Low-Temperature CO Adsorption on Ag+/SiO2 and Ag−ZSM-5: An FTIR Study. J Phys Chem B 1998. [DOI: 10.1021/jp983367n] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Konstantin Hadjiivanov
- Institut für physikalishe Chemie, Univeristät München, Sophienstr. 11, 80333 München, Germany
| | - Helmut Knözinger
- Institut für physikalishe Chemie, Univeristät München, Sophienstr. 11, 80333 München, Germany
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Müller BR, Calzaferri G. Thin Mo(CO)6–Y-zeolite layers: preparation and in situ transmission FTIR spectroscopy. ACTA ACUST UNITED AC 1996. [DOI: 10.1039/ft9969201633] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Gachard E, Belloni J, Subramanian MA. Optical and EPR spectroscopic studies of silver clusters in Ag,Na-Y zeolite by γ-irradiation. ACTA ACUST UNITED AC 1996. [DOI: 10.1039/jm9960600867] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Barbosa L, Calzaferri G. Chemisorption of pyrrole-siloxane on zeolite L and X: A thin layer infrared study. RESEARCH ON CHEMICAL INTERMEDIATES 1995. [DOI: 10.1163/156856795x00044] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Calzaferri G, Hädener K, Li J. Quasi-reversible silver zeolite electrode prepared by photochemical modification. ACTA ACUST UNITED AC 1991. [DOI: 10.1039/c39910000653] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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