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Elser M, Neige E, Berger T, Chiesa M, Giamello E, McKenna K, Risse T, Diwald O. On the Importance of Nanoparticle Necks and Carbon Impurities for Charge Trapping in TiO 2. J Phys Chem C Nanomater Interfaces 2023; 127:8778-8787. [PMID: 37197384 PMCID: PMC10184168 DOI: 10.1021/acs.jpcc.3c00430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 04/13/2023] [Indexed: 05/19/2023]
Abstract
Particle attachment and neck formation inside TiO2 nanoparticle networks determine materials performance in sensing, photo-electrochemistry, and catalysis. Nanoparticle necks can feature point defects with potential impact on the separation and recombination of photogenerated charges. Here, we investigated with electron paramagnetic resonance a point defect that traps electrons and predominantly forms in aggregated TiO2 nanoparticle systems. The associated paramagnetic center resonates in the g factor range between g = 2.0018 and 2.0028. Structure characterization and electron paramagnetic resonance data suggest that during materials processing, the paramagnetic electron center accumulates in the region of nanoparticle necks, where O2 adsorption and condensation can occur at cryogenic temperatures. Complementary density functional theory calculations reveal that residual carbon atoms, which potentially originate from synthesis, can substitute oxygen ions in the anionic sublattice, where they trap one or two electrons that mainly localize at the carbon. Their emergence upon particle neck formation is explained by the synthesis- and/or processing-induced particle attachment and aggregation facilitating carbon atom incorporation into the lattice. This study represents a substantial advance in linking dopants, point defects, and their spectroscopic fingerprints to microstructural features of oxide nanomaterials.
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Affiliation(s)
- Michael
J. Elser
- Institute
of Particle Technology (LFG), Friedrich-Alexander-Universität
Erlangen-Nürnberg, Cauerstraße 4, Erlangen 91058, Germany
| | - Ellie Neige
- Department
of Chemistry and Physics of Materials, Paris-Lodron
Universität Salzburg, Jakob-Haringerstrasse 2a, Salzburg 5020, Austria
| | - Thomas Berger
- Department
of Chemistry and Physics of Materials, Paris-Lodron
Universität Salzburg, Jakob-Haringerstrasse 2a, Salzburg 5020, Austria
| | - Mario Chiesa
- Department
of Chemistry and NIS Centre, University
of Torino, via Giuria 7, Torino I-10125, Italy
| | - Elio Giamello
- Department
of Chemistry and NIS Centre, University
of Torino, via Giuria 7, Torino I-10125, Italy
| | - Keith McKenna
- School
of Physics, Engineering and Technology, University of York, Heslington, York YO10
5DD, United Kingdom
| | - Thomas Risse
- Institut
für Chemie und Biochemie, Freie Universität
Berlin, Arnimallee 22, Berlin 14195, Germany
| | - Oliver Diwald
- Department
of Chemistry and Physics of Materials, Paris-Lodron
Universität Salzburg, Jakob-Haringerstrasse 2a, Salzburg 5020, Austria
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2
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Salvadori E, Bruzzese PC, Giamello E, Chiesa M. Single Metal Atoms on Oxide Surfaces: Assessing the Chemical Bond through 17O Electron Paramagnetic Resonance. Acc Chem Res 2022; 55:3706-3715. [PMID: 36442497 PMCID: PMC9774661 DOI: 10.1021/acs.accounts.2c00606] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
ConspectusEven in the gas phase single atoms possess catalytic properties, which can be crucially enhanced and modulated by the chemical interaction with a solid support. This effect, known as electronic metal-support interaction, encompasses charge transfer, orbital overlap, coordination structure, etc., in other words, all the crucial features of the chemical bond. These very features are the object of this Account, with specific reference to open-shell (paramagnetic) single metal atoms or ions on oxide supports. Such atomically dispersed species are part of the emerging class of heterogeneous catalysts known as single-atom catalysts (SACs). In these materials, atomic dispersion ensures maximum atom utilization and uniform active sites, whereby the nature of the chemical interaction between the metal and the oxide surface modulates the catalytic activity of the metal active site by tuning the energy of the frontier orbitals. A comprehensive set of examples includes fourth period metal atoms and ions in zeolites on insulating (e.g., MgO) or reducible (e.g., TiO2) oxides and are among the most relevant catalysts for a wealth of key processes of industrial and environmental relevance, from the abatement of NOx to the selective oxidation of hydrocarbons and the conversion of methane to methanol.There exist several spectroscopic techniques able to inform on the geometric and electronic structure of isolated single metal ion sites, but either they yield information averaged over the bulk or they lack description of the intimate features of chemical bonding, which include covalency, ionicity, electron and spin delocalization. All of these can be recovered at once by measuring the magnetic interactions between open-shell metals and the surrounding nuclei with Electron Paramagnetic Resonance (EPR) spectroscopy. In the case of oxides, this entails the synthesis of 17O isotopically enriched materials. We have established 17O EPR as a unique source of information about the local binding environment around oxygen of magnetic atoms or ions on different oxidic supports to rationalize structure-property relationships. Here, we will describe strategies for 17O surface enrichments and approaches to monitor the state of charge and spin delocalization of atoms or ions from K to Zn dispersed on oxide surfaces characterized by different chemical properties (i.e., basicity or reducibility). Emphasis is placed on chemical insight at the atomic-scale level achieved by 17O EPR, which is a crucial step in understanding the structure-property relationships of single metal atom catalysts and in enabling efficient design of future materials for a range of end uses.
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Affiliation(s)
- Enrico Salvadori
- Department
of Chemistry and NIS Centre of Excellence, University of Turin, via Giuria 9, 10125 Torino, Italy
| | - Paolo Cleto Bruzzese
- Department
of Chemistry and NIS Centre of Excellence, University of Turin, via Giuria 9, 10125 Torino, Italy,Felix
Bloch Institute for Solid State Physics, Leipzig University, Linnéstr. 5, 04103 Leipzig, Germany
| | - Elio Giamello
- Department
of Chemistry and NIS Centre of Excellence, University of Turin, via Giuria 9, 10125 Torino, Italy
| | - Mario Chiesa
- Department
of Chemistry and NIS Centre of Excellence, University of Turin, via Giuria 9, 10125 Torino, Italy,E-mail:
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3
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Cerrato E, Chiesa M, Giamello E, Livraghi S, Salvadori E, Paganini MC. Zinc oxide hollow spheres decorated with cerium dioxide. The role of morphology in the photoactivity of semiconducting oxides. J Phys Condens Matter 2022; 34:134001. [PMID: 34942602 DOI: 10.1088/1361-648x/ac4629] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Accepted: 12/23/2021] [Indexed: 06/14/2023]
Abstract
The photochemical activity of the recently proposed CeO2-ZnO photocatalytic material active under visible light has been improved by means of significant modifications of its morphology. A polymeric templating agent (Pluronic) has been used in the synthesis obtaining a particle morphology based on hollow spheres that is better defined in the case of high template concentration. The charge separation ability and the light-induced surface electron transfer under irradiation with visible polychromatic light in various ranges of wavelengths has been investigated by electron paramagnetic resonance. The reactivity of the photogenerated holes has been monitored by the spin trapping technique in the presence of DMPO. The hollow spheres morphology achieved through the synthesis here reported leads to systems with a higher photoactivity under visible irradiation than the same system displaying the classic platelets morphology. A parallel increase of the photocatalytic activity of this novel system in pollution remediation reactions is therefore predictable.
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Affiliation(s)
- Erik Cerrato
- Dipartimento di Chimica, via Giuria 7, 10125 Torino, Italy
| | - Mario Chiesa
- Dipartimento di Chimica, via Giuria 7, 10125 Torino, Italy
| | - Elio Giamello
- Dipartimento di Chimica, via Giuria 7, 10125 Torino, Italy
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4
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Chiesa M, Giamello E. On the Role and Applications of Electron Magnetic Resonance Techniques in Surface Chemistry and Heterogeneous Catalysis. Catal Letters 2021. [DOI: 10.1007/s10562-021-03576-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Abstract
Some relevant aspects of Electron Paramagnetic Resonance (EPR) applied to the fields of surface chemistry and heterogeneous catalysis are illustrated in this perspective paper that aims to show the potential of these techniques in describing critical features of surface structures and reactivity. Selected examples are employed covering distinct aspects of catalytic science from morphological analysis of surfaces to detailed descriptions of chemical bonding and catalytic sites topology. In conclusions the pros and cons related to the acquisition of EPR instrumentations in an advanced laboratory of surface chemistry and heterogeneous catalysis are briefly considered.
Graphic Abstract
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5
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Miletto I, Gionco C, Paganini MC, Martinotti S, Ranzato E, Giamello E, Marchese L, Gianotti E. Vis-NIR luminescent lanthanide-doped core-shell nanoparticles for imaging and photodynamic therapy. J Photochem Photobiol A Chem 2020. [DOI: 10.1016/j.jphotochem.2020.112840] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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6
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Chiesa M, Livraghi S, Paganini MC, Salvadori E, Giamello E. Nitrogen-doped semiconducting oxides. Implications on photochemical, photocatalytic and electronic properties derived from EPR spectroscopy. Chem Sci 2020; 11:6623-6641. [PMID: 34094123 PMCID: PMC8159384 DOI: 10.1039/d0sc02876b] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 06/22/2020] [Indexed: 01/16/2023] Open
Abstract
Engineering defects in semiconducting metal oxides is a challenge that remains at the forefront of materials chemistry research. Nitrogen has emerged as one of the most attractive elements able to tune the photochemical and photocatalytic properties of semiconducting oxides, boosting visible-light harvesting and charge separation events, key elements in promoting solar driven chemical reactions. Doping with nitrogen is also a strategy suggested to obtain p-type conduction properties in oxides showing n-type features in their pristine state and to impart collective magnetic properties to the same systems. Here, we review the evolution in the understanding of the role of nitrogen doping in modifying the photochemical and electronic properties of the most common semiconducting oxides used in mentioned applications including: TiO2, ZnO, SnO2 and zirconium titanates. With an emphasis on polycrystalline materials, we highlight the unique role of Electron Paramagnetic Resonance (EPR) spectroscopy in the direct detection of open-shell N-based defects and in the definition of their structural and electronic properties. Synthetic strategies for the insertion of nitrogen defects in the various matrices are also discussed, along with the influence of the corresponding low-lying energy states on the general electronic properties of the doped solids.
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Affiliation(s)
- Mario Chiesa
- Dipartimento di Chimica, Università degli Studi di Torino Torino Italy
| | - Stefano Livraghi
- Dipartimento di Chimica, Università degli Studi di Torino Torino Italy
| | | | - Enrico Salvadori
- Dipartimento di Chimica, Università degli Studi di Torino Torino Italy
| | - Elio Giamello
- Dipartimento di Chimica, Università degli Studi di Torino Torino Italy
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7
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Parrino F, Livraghi S, Giamello E, Ceccato R, Palmisano L. Role of Hydroxyl, Superoxide, and Nitrate Radicals on the Fate of Bromide Ions in Photocatalytic TiO2 Suspensions. ACS Catal 2020. [DOI: 10.1021/acscatal.0c02010] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- F. Parrino
- Department of Industrial Engineering, University of Trento, Via Sommarive 9, 38123 Trento, Italy
| | - S. Livraghi
- Department of Chemistry and NIS, University of Torino, Via P. Giuria 7, 10125 Torino, Italy
| | - E. Giamello
- Department of Chemistry and NIS, University of Torino, Via P. Giuria 7, 10125 Torino, Italy
| | - R. Ceccato
- Department of Industrial Engineering, University of Trento, Via Sommarive 9, 38123 Trento, Italy
| | - L. Palmisano
- Department of Engineering, University of Palermo, Viale delle Scienze Ed. 6, 90128 Palermo, Italy
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8
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Giamello E, Pacchioni G. Applied vs fundamental research in heterogeneous photocatalysis: problems and perspectives. An introduction to 'physical principles of photocatalysis'. J Phys Condens Matter 2020; 32:360301. [PMID: 32396884 DOI: 10.1088/1361-648x/ab926b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 05/12/2020] [Indexed: 06/11/2023]
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9
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Yurdakal S, Çetinkaya S, Augugliaro V, Palmisano G, Soria J, Sanz J, Torralvo MJ, Livraghi S, Giamello E, Garlisi C. Alkaline treatment as a means to boost the activity of TiO2 in selective photocatalytic processes. Catal Sci Technol 2020. [DOI: 10.1039/d0cy00755b] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
In this work, the activity enhancement of TiO2 photocatalysts by alkaline treatment has been investigated.
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Affiliation(s)
- Sedat Yurdakal
- Kimya Bölümü
- Fen-Edebiyat Fakültesi
- Afyon Kocatepe Üniversitesi
- 03200 Afyonkarahisar
- Turkey
| | - Sıdıka Çetinkaya
- Kimya Bölümü
- Fen-Edebiyat Fakültesi
- Afyon Kocatepe Üniversitesi
- 03200 Afyonkarahisar
- Turkey
| | - Vincenzo Augugliaro
- “Schiavello-Grillone” Photocatalysis Group
- Dipartimento di Energia
- Ingegneria dell'Informazione e Modelli Matematici (DEIM)
- Università degli Studi di Palermo
- 90128 Palermo
| | - Giovanni Palmisano
- Department of Chemical Engineering
- Khalifa University of Science and Technology
- Abu Dhabi
- United Arab Emirates
- Research and Innovation on CO2 and H2 (RICH) Center
| | - Javier Soria
- Instituto de Ciencia de Materiales
- CSIC
- 28049 Madrid
- Spain
| | - Jesus Sanz
- Instituto de Catálisis y Petroleoquímica
- CSIC
- 28049 Madrid
- Spain
| | - Maria Jose Torralvo
- Facultad de Ciencias Químicas
- Universidad Complutense de Madrid
- 28040 Madrid
- Spain
| | - Stefano Livraghi
- Dipartimento di Chimica and NIS
- University of Torino
- 10125 Torino
- Italy
| | - Elio Giamello
- Dipartimento di Chimica and NIS
- University of Torino
- 10125 Torino
- Italy
| | - Corrado Garlisi
- Department of Chemical Engineering
- Khalifa University of Science and Technology
- Abu Dhabi
- United Arab Emirates
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10
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Polliotto V, Albanese E, Livraghi S, Agnoli S, Pacchioni G, Giamello E. Structural, electronic and photochemical properties of cerium-doped zirconium titanate. Catal Today 2020. [DOI: 10.1016/j.cattod.2018.09.026] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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11
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Chiesa M, Giamello E, Livraghi S, Paganini MC, Polliotto V, Salvadori E. Electron magnetic resonance in heterogeneous photocatalysis research. J Phys Condens Matter 2019; 31:444001. [PMID: 31311893 DOI: 10.1088/1361-648x/ab32c6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The contribution of electron magnetic resonance techniques, and in particular of CW-EPR, to the experimental research on photocatalytic phenomena is illustrated in this paper with selected examples. In the first part of the paper the role of EPR in unravelling the nature and the features of extrinsic point defects in semiconducting oxides is epitomized using the important example of the photoactive nitrogen center in various semiconducting oxides. In the second part we describe how EPR can monitor the processes that follow the initial photoinduced charge separation in photocatalysis, namely the stabilisation, migration and surface reactivity of electrons and holes. Finally, we will discuss how the role of EPR in photocatalysis is not limited to monitor phenomena occurring in the solid or at its surface but it can be extended to the investigation of the liquid phase by employing the spin trapping techniques to monitor the nature and the concentration of the reactive free radicals formed along the photocatalytic process.
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Affiliation(s)
- Mario Chiesa
- Dipartimento di Chimica, Università di Torino, Via P. Giuria 7, 10125., Torino, Italy
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12
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Morra E, Signorile M, Salvadori E, Bordiga S, Giamello E, Chiesa M. Back Cover: Nature and Topology of Metal–Oxygen Binding Sites in Zeolite Materials:
17
O High‐Resolution EPR Spectroscopy of Metal‐Loaded ZSM‐5 (Angew. Chem. Int. Ed. 36/2019). Angew Chem Int Ed Engl 2019. [DOI: 10.1002/anie.201909720] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Elena Morra
- Department of ChemistryUniversity of Torino Via Giuria, 7 10125 Torino Italy
| | - Matteo Signorile
- Department of ChemistryUniversity of Torino Via Giuria, 7 10125 Torino Italy
| | - Enrico Salvadori
- Department of ChemistryUniversity of Torino Via Giuria, 7 10125 Torino Italy
| | - Silvia Bordiga
- Department of ChemistryUniversity of Torino Via Giuria, 7 10125 Torino Italy
| | - Elio Giamello
- Department of ChemistryUniversity of Torino Via Giuria, 7 10125 Torino Italy
| | - Mario Chiesa
- Department of ChemistryUniversity of Torino Via Giuria, 7 10125 Torino Italy
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13
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Morra E, Signorile M, Salvadori E, Bordiga S, Giamello E, Chiesa M. Rücktitelbild: Nature and Topology of Metal–Oxygen Binding Sites in Zeolite Materials:
17
O High‐Resolution EPR Spectroscopy of Metal‐Loaded ZSM‐5 (Angew. Chem. 36/2019). Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201909720] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Elena Morra
- Department of ChemistryUniversity of Torino Via Giuria, 7 10125 Torino Italy
| | - Matteo Signorile
- Department of ChemistryUniversity of Torino Via Giuria, 7 10125 Torino Italy
| | - Enrico Salvadori
- Department of ChemistryUniversity of Torino Via Giuria, 7 10125 Torino Italy
| | - Silvia Bordiga
- Department of ChemistryUniversity of Torino Via Giuria, 7 10125 Torino Italy
| | - Elio Giamello
- Department of ChemistryUniversity of Torino Via Giuria, 7 10125 Torino Italy
| | - Mario Chiesa
- Department of ChemistryUniversity of Torino Via Giuria, 7 10125 Torino Italy
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14
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Morra E, Signorile M, Salvadori E, Bordiga S, Giamello E, Chiesa M. Nature and Topology of Metal-Oxygen Binding Sites in Zeolite Materials: 17 O High-Resolution EPR Spectroscopy of Metal-Loaded ZSM-5. Angew Chem Int Ed Engl 2019; 58:12398-12403. [PMID: 31294524 DOI: 10.1002/anie.201906488] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 07/02/2019] [Indexed: 11/05/2022]
Abstract
Determining structural models is pivotal to the rational understanding and development of heterogeneous catalytic systems. A paradigmatic case is represented by open-shell metals supported on oxides, where the catalytic properties crucially depend on the nature of the metal-oxygen bonds and the extent of charge and spin transfer. Through a combination of selective 17 O isotopic enrichment and the unique properties of open-shell s-state monovalent Group 12 cations, we derive a site-specific topological description of active sites in an MFI zeolite. We show that just a few selected sites out of all possible are populated and that the relative occupancies depend on the specific properties of the metal, and we provide maps of charge and spin transfer at the metal-oxygen interface. This approach is not restricted to zeotype materials, rather it is applicable to any catalysts supported on oxygen-containing materials.
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Affiliation(s)
- Elena Morra
- Department of Chemistry, University of Torino, Via Giuria, 7, 10125, Torino, Italy
| | - Matteo Signorile
- Department of Chemistry, University of Torino, Via Giuria, 7, 10125, Torino, Italy
| | - Enrico Salvadori
- Department of Chemistry, University of Torino, Via Giuria, 7, 10125, Torino, Italy
| | - Silvia Bordiga
- Department of Chemistry, University of Torino, Via Giuria, 7, 10125, Torino, Italy
| | - Elio Giamello
- Department of Chemistry, University of Torino, Via Giuria, 7, 10125, Torino, Italy
| | - Mario Chiesa
- Department of Chemistry, University of Torino, Via Giuria, 7, 10125, Torino, Italy
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15
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Morra E, Signorile M, Salvadori E, Bordiga S, Giamello E, Chiesa M. Nature and Topology of Metal–Oxygen Binding Sites in Zeolite Materials:
17
O High‐Resolution EPR Spectroscopy of Metal‐Loaded ZSM‐5. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201906488] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Elena Morra
- Department of ChemistryUniversity of Torino Via Giuria, 7 10125 Torino Italy
| | - Matteo Signorile
- Department of ChemistryUniversity of Torino Via Giuria, 7 10125 Torino Italy
| | - Enrico Salvadori
- Department of ChemistryUniversity of Torino Via Giuria, 7 10125 Torino Italy
| | - Silvia Bordiga
- Department of ChemistryUniversity of Torino Via Giuria, 7 10125 Torino Italy
| | - Elio Giamello
- Department of ChemistryUniversity of Torino Via Giuria, 7 10125 Torino Italy
| | - Mario Chiesa
- Department of ChemistryUniversity of Torino Via Giuria, 7 10125 Torino Italy
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16
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García-López E, Marcì G, Pomilla F, Paganini M, Gionco C, Giamello E, Palmisano L. ZrO2 Based materials as photocatalysts for 2-propanol oxidation by using UV and solar light irradiation and tests for CO2 reduction. Catal Today 2018. [DOI: 10.1016/j.cattod.2018.01.030] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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17
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Polliotto V, Livraghi S, Krukowska A, Dozzi MV, Zaleska-Medynska A, Selli E, Giamello E. Copper-Modified TiO 2 and ZrTiO 4: Cu Oxidation State Evolution during Photocatalytic Hydrogen Production. ACS Appl Mater Interfaces 2018; 10:27745-27756. [PMID: 30048108 DOI: 10.1021/acsami.8b05528] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
In the present work, two H2 evolution photocatalysts were prepared by employing two different oxides, TiO2 and zirconium titanate (ZrTiO4), as the support of various copper phases. For both the supports the same Cu loading (0.5% w/w) was adopted, but two different impregnation procedures have been followed, leading to different forms of Cu in the final composite material that are: (i) Cu(II) species dispersed on the oxide surface and (ii) Cu2O particles dispersed on the oxide surface. The present paper based on the parallel use of photocatalytic test and spectroscopic analysis performed in catalytic conditions illustrates the evolution of photocatalytic systems occurring during the H2 evolution reaction tests, pointing out that the as-prepared materials represent a pre-catalyst and they are modified during irradiation leading to the real working systems different from the starting ones. The herein presented spectroscopic analysis aims to contribute to the living debate on the oxidation state of copper in mixed Cu/oxide materials and on its role in hydrogen evolution under photocatalytic conditions.
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Affiliation(s)
- Valeria Polliotto
- Dipartimento di Chimica and NIS , Università di Torino , Via P. Giuria 7 , 10125 Torino , Italy
| | - Stefano Livraghi
- Dipartimento di Chimica and NIS , Università di Torino , Via P. Giuria 7 , 10125 Torino , Italy
| | - Anna Krukowska
- Department of Environmental Technology, Faculty of Chemistry , University of Gdansk , 80-308 Gdansk , Poland
| | - Maria Vittoria Dozzi
- Dipartimento di Chimica , Università degli Studi di Milano , Via Golgi 19 , 20133 Milano , Italy
| | - Adriana Zaleska-Medynska
- Department of Environmental Technology, Faculty of Chemistry , University of Gdansk , 80-308 Gdansk , Poland
| | - Elena Selli
- Dipartimento di Chimica , Università degli Studi di Milano , Via Golgi 19 , 20133 Milano , Italy
| | - Elio Giamello
- Dipartimento di Chimica and NIS , Università di Torino , Via P. Giuria 7 , 10125 Torino , Italy
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18
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Hernández S, Gionco C, Husak T, Castellino M, Muñoz-Tabares JA, Tolod KR, Giamello E, Paganini MC, Russo N. Insights Into the Sunlight-Driven Water Oxidation by Ce and Er-Doped ZrO 2. Front Chem 2018; 6:368. [PMID: 30186832 PMCID: PMC6113700 DOI: 10.3389/fchem.2018.00368] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2018] [Accepted: 07/30/2018] [Indexed: 12/03/2022] Open
Abstract
In the present work, the activity of Ce and Er-doped ZrO2 nanopowders for sun-driven photocatalytic water oxidation has been investigated. ZrO2 powders with tunable amounts of tetragonal, monoclinic and cubic polymorphs have been synthesized by introducing Ce and Er (from 0.5 to 10 mol % on an oxide basis) through hydrothermal method. The aim of this work is to investigate the role of rare earth (RE) ions rich of electrons (Er3+) and with entirely empty levels (Ce4+) in the ZrO2 matrix for the sun-driven photocatalytic water oxidation reaction. The samples have been characterized by means of UV-Vis spectroscopy, X-Ray diffraction (XRD), N2 adsorption, X-ray photoelectron spectrophotometry (XPS) and transmission electronic microscopy (TEM) with energy dispersive spectroscopy (EDS). With respect to the bare ZrO2 mainly containing monoclinic (m-) phase, an increasing amount of rare-earth (RE) dopant was found to improve the specific BET surface area and to stabilize the tetragonal (t-) or cubic (c-) polymorphs of ZrO2 at room temperature. XRD data confirmed that dopants were mainly inserted in the t-ZrO2 phase. The photocatalytic O2 evolution from water under AM 1.5 G simulated sunlight illumination of the prepared samples have been correlated with their optical, structural and chemical properties. The effect of the dopant concentration on the chemical-physical and photocatalytic properties of the Er- and Ce-doped ZrO2 materials was elucidated. The samples with 5% of RE oxide were the most active, i.e., three times more than pure zirconia. Their superior photocatalytic activity was found to be mainly correlated to two factors: (i) an optimal surface concentration of RE ions of about 3.7%, which increased charge carriers separation in the photocatalysts surface due more superficial defects of the t-ZrO2 and a higher surface area, thus enhancing the reaction kinetics, (ii) a controlled amount of monoclinic vs. tetragonal (or cubic) polymorphs of zirconia with an optimum ratio of about 70/30 of t-ZrO2/m-ZrO2. Instead, the increased ability of the RE-doped ZrO2 to harvest visible light was found to have a secondary role on the photocatalytic activity of the Ce-doped ZrO2 material.
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Affiliation(s)
- Simelys Hernández
- CREST Group, Department of Applied Science and Technology (DISAT), Politecnico di Torino, Turin, Italy
| | - Chiara Gionco
- Department of Chemistry, University of Torino, Turin, Italy
| | - Thomas Husak
- CREST Group, Department of Applied Science and Technology (DISAT), Politecnico di Torino, Turin, Italy
| | - Micaela Castellino
- Center for Sustainable Future Technologies (CSFT), Istituto Italiano di Tecnologia, Turin, Italy
| | - José A Muñoz-Tabares
- Center for Sustainable Future Technologies (CSFT), Istituto Italiano di Tecnologia, Turin, Italy
| | - Kristine R Tolod
- CREST Group, Department of Applied Science and Technology (DISAT), Politecnico di Torino, Turin, Italy.,Ecole Doctorale de Chimie, Université Claude Bernard Lyon 1, Lyon, France
| | - Elio Giamello
- Department of Chemistry, University of Torino, Turin, Italy
| | | | - Nunzio Russo
- CREST Group, Department of Applied Science and Technology (DISAT), Politecnico di Torino, Turin, Italy
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Parrino F, Livraghi S, Giamello E, Palmisano L. The Existence of Nitrate Radicals in Irradiated TiO
2
Aqueous Suspensions in the Presence of Nitrate Ions. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201804879] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Francesco Parrino
- Dipartimento di EnergiaIngegneria dell'Informazione e Modelli Matematici (DEIM)University of Palermo viale delle Scienze Ed. 6 90128 Palermo Italy
| | - Stefano Livraghi
- Dipartimento di Chimica and NISUniversity of Torino Via P. Giuria 7 10125 Torino Italy
| | - Elio Giamello
- Dipartimento di Chimica and NISUniversity of Torino Via P. Giuria 7 10125 Torino Italy
| | - Leonardo Palmisano
- Dipartimento di EnergiaIngegneria dell'Informazione e Modelli Matematici (DEIM)University of Palermo viale delle Scienze Ed. 6 90128 Palermo Italy
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20
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Parrino F, Livraghi S, Giamello E, Palmisano L. The Existence of Nitrate Radicals in Irradiated TiO 2 Aqueous Suspensions in the Presence of Nitrate Ions. Angew Chem Int Ed Engl 2018; 57:10702-10706. [PMID: 29938878 DOI: 10.1002/anie.201804879] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Revised: 06/04/2018] [Indexed: 11/08/2022]
Abstract
Evidence of the existence of nitrate radical in irradiated aqueous TiO2 suspensions in the presence of nitrate ions are reported for the first time. The joint use of UV/Vis and EPR spectroscopy showed that nitrate radicals are formed by hole induced oxidation of nitrate ions. Photocatalytic degradation of a model alkene compound allowed to highlight the presence of an intermediate organic nitrate deriving from nitrate radical attack to the double bond of the substrate. These results not only allow deeper understanding of photocatalytic processes, but open the route to new green photocatalytic syntheses initiated by nitrate radicals and to new insights in the field of atmospheric chemistry.
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Affiliation(s)
- Francesco Parrino
- Dipartimento di Energia, Ingegneria dell'Informazione e Modelli Matematici (DEIM), University of Palermo, viale delle Scienze Ed. 6, 90128, Palermo, Italy
| | - Stefano Livraghi
- Dipartimento di Chimica and NIS, University of Torino, Via P. Giuria 7, 10125, Torino, Italy
| | - Elio Giamello
- Dipartimento di Chimica and NIS, University of Torino, Via P. Giuria 7, 10125, Torino, Italy
| | - Leonardo Palmisano
- Dipartimento di Energia, Ingegneria dell'Informazione e Modelli Matematici (DEIM), University of Palermo, viale delle Scienze Ed. 6, 90128, Palermo, Italy
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21
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Livraghi S, Barbero N, Agnoli S, Barolo C, Granozzi G, Sauvage F, Giamello E. A multi-technique comparison of the electronic properties of pristine and nitrogen-doped polycrystalline SnO2. Phys Chem Chem Phys 2018; 18:22617-27. [PMID: 27477515 DOI: 10.1039/c6cp02822e] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Nitrogen doped tin(iv) oxide (SnO2) materials in the form of nanometric powders have been prepared by precipitation with ammonia. Their properties have been compared with those of undoped materials obtained in a similar way using various physical techniques such as photoelectron spectroscopies (XPS and UPS), UV-Vis-NIR spectroscopy and electron paramagnetic resonance (EPR). Nitrogen doping leads to the formation of various nitrogen containing species, the more relevant of which is a nitride-type ionic species, based on the substitution of a lattice oxygen atom with a nitrogen atom. This species exists in two forms, paramagnetic (hole centre, formally N(2-)) and diamagnetic (N(3-)). The mutual ratio of the two species varies according to the oxidation state of the material. The doped solid, like most of the semiconducting oxides, tends to lose oxygen forming oxygen vacancies upon annealing under vacuum and leaving an excess of electrons in the solid. The stoichiometry of the solid can thus be markedly changed depending on the external conditions. Excess electrons are present both as itinerant electrons in the conduction band and as Sn(ii) states lying close to the valence band maximum. The presence of nitride-type centres, which are low energy states located below the top of the valence band, decreases the energy cost for the formation of oxygen vacancies by O2 release from the lattice. This particular feature of the doped system represents a severe limit to the preparation of a p-type SnO2via nitrogen doping.
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Affiliation(s)
- S Livraghi
- Dipartimento di Chimica, Università di Torino and NIS, Centre for Nanostructured Interfaces and Surfaces, Via P. Giuria 7, I - 10125 Torino, Italy
| | - N Barbero
- Dipartimento di Chimica, Università di Torino and NIS, Centre for Nanostructured Interfaces and Surfaces, Via P. Giuria 7, I - 10125 Torino, Italy and Laboratoire de Réactivité et Chimie des Solides, Université de Picardie Jules Verne, CNRS UMR 7314, 33 rue Saint Leu, 80039 Amiens, France
| | - S Agnoli
- Dipartimento di Scienze Chimiche, Università di Padova, Via Marzolo 1, 35131 Padova, Italy
| | - C Barolo
- Dipartimento di Chimica, Università di Torino and NIS, Centre for Nanostructured Interfaces and Surfaces, Via P. Giuria 7, I - 10125 Torino, Italy
| | - G Granozzi
- Dipartimento di Scienze Chimiche, Università di Padova, Via Marzolo 1, 35131 Padova, Italy
| | - F Sauvage
- Laboratoire de Réactivité et Chimie des Solides, Université de Picardie Jules Verne, CNRS UMR 7314, 33 rue Saint Leu, 80039 Amiens, France
| | - E Giamello
- Dipartimento di Chimica, Università di Torino and NIS, Centre for Nanostructured Interfaces and Surfaces, Via P. Giuria 7, I - 10125 Torino, Italy
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22
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Cerrato E, Gionco C, Paganini MC, Giamello E. Photoactivity properties of ZnO doped with cerium ions: an EPR study. J Phys Condens Matter 2017; 29:444001. [PMID: 28850046 DOI: 10.1088/1361-648x/aa88f7] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
In the present study, we investigated the effect of cerium doping in zinc oxide matrix, used as photoactive material. Cerium ions into the matrix of ZnO can act like a 'trap' for the electrons, lowering the e -/h + recombination rate and so increasing the photocatalytic efficiency of the ZnO. We synthesised doped samples using a simple precipitation route. The amount of dopant used was, 1 and 10% molar. The samples have been studied via x-ray diffraction measurements for the structural characterisation; UV-visible diffuse reflectance was used for the optical analysis; Branauer-Emmett-Teller (BET) model for the measurement of the surface area. Finally, the samples have been analysed via electron paramagnetic resonance (EPR) spectroscopy for the electronic characterisation and for testing their photoactivity. The spin trapping technique was also use to measure the amount of stable radical adducts formed via reaction of OH• radicals with molecules of the DMPO (5,5-dimethyl-1-pyrroline-N-oxide) spin probe.
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Affiliation(s)
- Erik Cerrato
- Dipartimento di Chimica and NIS Centre, Università degli Studi di Torino, via Giuria 7, I-10125 Torino, Italy
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23
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Morra E, Giamello E, Chiesa M. EPR approaches to heterogeneous catalysis. The chemistry of titanium in heterogeneous catalysts and photocatalysts. J Magn Reson 2017; 280:89-102. [PMID: 28579105 DOI: 10.1016/j.jmr.2017.02.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Revised: 02/09/2017] [Accepted: 02/10/2017] [Indexed: 06/07/2023]
Abstract
Paramagnetic species are often involved in catalytic or photocatalytic reactions occurring at the solid-gas interface of heterogeneous catalysts. In this contribution we will provide an overview of the wealth and breadth of information that can be obtained from EPR in the characterization of paramagnetic species in such systems, illustrating the advantages that modern pulsed EPR methodologies can offer in monitoring the elementary processes occurring within the coordination sphere of surface transition-metal ions. To do so we selected three representative systems, where titanium ions in low oxidation states act as active catalytic sites, trying to outline the methodological approaches which characterize the application of EPR techniques and the questions that can be answered and addressed relative to the characterization of heterogeneous catalytic materials.
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Affiliation(s)
- Elena Morra
- Dipartimento di Chimica, Università di Torino, Via Giuria, 7, 10125 Torino, Italy
| | - Elio Giamello
- Dipartimento di Chimica, Università di Torino, Via Giuria, 7, 10125 Torino, Italy
| | - Mario Chiesa
- Dipartimento di Chimica, Università di Torino, Via Giuria, 7, 10125 Torino, Italy.
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24
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25
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Fubini B, Giamello E, Della Gatta G. Microcalorimetric study of the surface rehydration at 150 °C of variously dehydrated « eta » alumina. ACTA ACUST UNITED AC 2017. [DOI: 10.1051/jcp/1978750578] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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26
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27
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Moreno-González M, Palomares AE, Chiesa M, Boronat M, Giamello E, Blasco T. Evidence of a Cu2+–Alkane Interaction in Cu-Zeolite Catalysts Crucial for the Selective Catalytic Reduction of NOx with Hydrocarbons. ACS Catal 2017. [DOI: 10.1021/acscatal.6b03473] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- M. Moreno-González
- Instituto
de Tecnología Química, Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas (UPV-CSIC), Avda. de los Naranjos s/n, 46022 Valencia, Spain
| | - A. E. Palomares
- Instituto
de Tecnología Química, Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas (UPV-CSIC), Avda. de los Naranjos s/n, 46022 Valencia, Spain
| | - M. Chiesa
- Dipartimento
di Chimica, Università di Torino, Via Giuria, 7, 10125 Torino, Italy
| | - M. Boronat
- Instituto
de Tecnología Química, Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas (UPV-CSIC), Avda. de los Naranjos s/n, 46022 Valencia, Spain
| | - E. Giamello
- Dipartimento
di Chimica, Università di Torino, Via Giuria, 7, 10125 Torino, Italy
| | - T. Blasco
- Instituto
de Tecnología Química, Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas (UPV-CSIC), Avda. de los Naranjos s/n, 46022 Valencia, Spain
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28
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García‐López EI, Marcì G, Pomilla FR, Liotta LF, Megna B, Paganini MC, Gionco C, Giamello E, Palmisano L. Improved (Photo)catalytic Propene Hydration in a Gas/Solid System by Using Heteropolyacid/Oxide Composites: Electron Paramagnetic Resonance, Acidity, and Role of Water. Eur J Inorg Chem 2017. [DOI: 10.1002/ejic.201601396] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Elisa I. García‐López
- “Schiavello‐Grillone” Photocatalysis Group Dipartimento di Energia, Ingegneria dell'informazione e modelli Matematici (DEIM) Università di Palermo Viale delle Scienze 90128 Palermo Italy
| | - Giuseppe Marcì
- “Schiavello‐Grillone” Photocatalysis Group Dipartimento di Energia, Ingegneria dell'informazione e modelli Matematici (DEIM) Università di Palermo Viale delle Scienze 90128 Palermo Italy
| | - Francesca R. Pomilla
- “Schiavello‐Grillone” Photocatalysis Group Dipartimento di Energia, Ingegneria dell'informazione e modelli Matematici (DEIM) Università di Palermo Viale delle Scienze 90128 Palermo Italy
| | - Leonarda F. Liotta
- Istituto per Lo Studio dei Materiali Nanostrutturati (ISMN)‐CNR via Ugo La Malfa 153 90146 Palermo Italy
| | - Bartolomeo Megna
- Dipartimento Ingegneria Civile, Ambientale, Aerospaziale, dei Materiali Viale delle Scienze 90128 Palermo Italy
| | - Maria C. Paganini
- Dipartimento di Chimica Università di Torino via Giuria 7 10125 Torino Italy
| | - Chiara Gionco
- Dipartimento di Chimica Università di Torino via Giuria 7 10125 Torino Italy
| | - Elio Giamello
- Dipartimento di Chimica Università di Torino via Giuria 7 10125 Torino Italy
| | - Leonardo Palmisano
- “Schiavello‐Grillone” Photocatalysis Group Dipartimento di Energia, Ingegneria dell'informazione e modelli Matematici (DEIM) Università di Palermo Viale delle Scienze 90128 Palermo Italy
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29
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Chiesa M, Livraghi S, Giamello E, Albanese E, Pacchioni G. Ferromagnetic Interactions in Highly Stable, Partially Reduced TiO 2 : The S=2 State in Anatase. Angew Chem Int Ed Engl 2017; 56:2604-2607. [PMID: 28128485 DOI: 10.1002/anie.201610973] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Indexed: 11/07/2022]
Abstract
We report direct evidence for quintuplet spin states in a particular kind of reduced TiO2 anatase obtained by the mild oxidation of TiB2 under hydrothermal conditions. Continuous-wave and pulse EPR spectroscopy at X and Q band frequencies provide compelling evidence for the presence of S=2 states, stable in a wide range of temperatures up to room temperature. A tentative model, corroborated by spin-polarized DFT calculations, is proposed, which consists of four ferromagnetically interacting Ti3+ ions with distances ranging from 0.5 nm to 0.8 nm and tetrahedral arrangement.
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Affiliation(s)
- Mario Chiesa
- Dipartimento di Chimica, Università degli Studi di Torino, Via Giuria 7, 10125, Torino, Italy
| | - Stefano Livraghi
- Dipartimento di Chimica, Università degli Studi di Torino, Via Giuria 7, 10125, Torino, Italy
| | - Elio Giamello
- Dipartimento di Chimica, Università degli Studi di Torino, Via Giuria 7, 10125, Torino, Italy
| | - Elisa Albanese
- Dipartimento di Scienza dei Materiali, Università di Milano Bicocca, Via Cozzi 55, Milano, Italy
| | - Gianfranco Pacchioni
- Dipartimento di Scienza dei Materiali, Università di Milano Bicocca, Via Cozzi 55, Milano, Italy
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30
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Chiesa M, Livraghi S, Giamello E, Albanese E, Pacchioni G. Ferromagnetic Interactions in Highly Stable, Partially Reduced TiO2
: The S=
2 State in Anatase. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201610973] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Mario Chiesa
- Dipartimento di Chimica; Università degli Studi di Torino; Via Giuria 7 10125 Torino Italy
| | - Stefano Livraghi
- Dipartimento di Chimica; Università degli Studi di Torino; Via Giuria 7 10125 Torino Italy
| | - Elio Giamello
- Dipartimento di Chimica; Università degli Studi di Torino; Via Giuria 7 10125 Torino Italy
| | - Elisa Albanese
- Dipartimento di Scienza dei Materiali; Università di Milano Bicocca; Via Cozzi 55 Milano Italy
| | - Gianfranco Pacchioni
- Dipartimento di Scienza dei Materiali; Università di Milano Bicocca; Via Cozzi 55 Milano Italy
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31
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Baravalle R, Valetti F, Catucci G, Gambarotta G, Chiesa M, Maurelli S, Giamello E, Barone I, Catalano S, Andò S, Di Nardo G, Gilardi G. Effect of sildenafil on human aromatase activity: From in vitro structural analysis to catalysis and inhibition in cells. J Steroid Biochem Mol Biol 2017; 165:438-447. [PMID: 27616271 DOI: 10.1016/j.jsbmb.2016.09.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Revised: 09/05/2016] [Accepted: 09/06/2016] [Indexed: 11/15/2022]
Abstract
Aromatase catalyses the conversion of androgens into estrogens and is a well-known target for breast cancer therapy. As it has been suggested that its activity is affected by inhibitors of phosphodiesterase-5, this work investigates the potential interaction of sildenafil with aromatase. This is carried out both at molecular level through structural and kinetics assays applied to the purified enzyme, and at cellular level using neuronal and breast cancer cell lines. Sildenafil is found to bind to aromatase with a KD of 0.58±0.05μM acting as a partial and mixed inhibitor with a maximal inhibition of 35±2%. Hyperfine sublevel correlation spectroscopy and docking studies show that sildenafil binds to the heme iron via its 6th axial water ligand. These results also provide information on the starting molecular scaffold for the development of new generations of drugs designed to inhibit aromatase as well as phosphodiesterase-5, a new emerging target for breast cancer therapy.
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Affiliation(s)
- Roberta Baravalle
- Department of Life Sciences and Systems Biology, University of Torino, via Accademia Albertina 13, 10123 Torino, Italy
| | - Francesca Valetti
- Department of Life Sciences and Systems Biology, University of Torino, via Accademia Albertina 13, 10123 Torino, Italy
| | - Gianluca Catucci
- Department of Life Sciences and Systems Biology, University of Torino, via Accademia Albertina 13, 10123 Torino, Italy
| | - Giovanna Gambarotta
- Department of Clinical and Biological Sciences, University of Torino, Regione Gonzole, 10-10043 Orbassano, Italy
| | - Mario Chiesa
- Department of Chemistry, University of Torino, via Pietro Giuria 7, 10125, Torino, Italy
| | - Sara Maurelli
- Department of Chemistry, University of Torino, via Pietro Giuria 7, 10125, Torino, Italy
| | - Elio Giamello
- Department of Chemistry, University of Torino, via Pietro Giuria 7, 10125, Torino, Italy
| | - Ines Barone
- Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, Arcavacata di Rende, CS, Italy
| | - Stefania Catalano
- Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, Arcavacata di Rende, CS, Italy
| | - Sebastiano Andò
- Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, Arcavacata di Rende, CS, Italy
| | - Giovanna Di Nardo
- Department of Life Sciences and Systems Biology, University of Torino, via Accademia Albertina 13, 10123 Torino, Italy; CrisDi, Interdepartmental Center for Crystallography, via Pietro Giuria 7, 10125, Torino, Italy.
| | - Gianfranco Gilardi
- Department of Life Sciences and Systems Biology, University of Torino, via Accademia Albertina 13, 10123 Torino, Italy; CrisDi, Interdepartmental Center for Crystallography, via Pietro Giuria 7, 10125, Torino, Italy.
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32
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Panarelli EG, Livraghi S, Maurelli S, Polliotto V, Chiesa M, Giamello E. Role of surface water molecules in stabilizing trapped hole centres in titanium dioxide (anatase) as monitored by electron paramagnetic resonance. J Photochem Photobiol A Chem 2016. [DOI: 10.1016/j.jphotochem.2016.02.015] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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33
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Morra S, Maurelli S, Chiesa M, Mulder DW, Ratzloff MW, Giamello E, King PW, Gilardi G, Valetti F. The effect of a C298D mutation in CaHydA [FeFe]-hydrogenase: Insights into the protein-metal cluster interaction by EPR and FTIR spectroscopic investigation. Biochim Biophys Acta 2015; 1857:98-106. [PMID: 26482707 DOI: 10.1016/j.bbabio.2015.10.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Revised: 10/01/2015] [Accepted: 10/15/2015] [Indexed: 01/17/2023]
Abstract
A conserved cysteine located in the signature motif of the catalytic center (H-cluster) of [FeFe]-hydrogenases functions in proton transfer. This residue corresponds to C298 in Clostridium acetobutylicum CaHydA. Despite the chemical and structural difference, the mutant C298D retains fast catalytic activity, while replacement with any other amino acid causes significant activity loss. Given the proximity of C298 to the H-cluster, the effect of the C298D mutation on the catalytic center was studied by continuous wave (CW) and pulse electron paramagnetic resonance (EPR) and by Fourier transform infrared (FTIR) spectroscopies. Comparison of the C298D mutant with the wild type CaHydA by CW and pulse EPR showed that the electronic structure of the center is not altered. FTIR spectroscopy confirmed that absorption peak values observed in the mutant are virtually identical to those observed in the wild type, indicating that the H-cluster is not generally affected by the mutation. Significant differences were observed only in the inhibited state Hox-CO: the vibrational modes assigned to the COexo and Fed-CO in this state are shifted to lower values in C298D, suggesting different interaction of these ligands with the protein moiety when C298 is changed to D298. More relevant to the catalytic cycle, the redox equilibrium between the Hox and Hred states is modified by the mutation, causing a prevalence of the oxidized state. This work highlights how the interactions between the protein environment and the H-cluster, a dynamic closely interconnected system, can be engineered and studied in the perspective of designing bio-inspired catalysts and mimics.
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Affiliation(s)
- Simone Morra
- Department of Life Sciences and Systems Biology, University of Torino, Torino 10133, Italy
| | - Sara Maurelli
- Department of Chemistry, University of Torino, Torino 10133, Italy
| | - Mario Chiesa
- Department of Chemistry, University of Torino, Torino 10133, Italy
| | - David W Mulder
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401, USA
| | - Michael W Ratzloff
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401, USA
| | - Elio Giamello
- Department of Chemistry, University of Torino, Torino 10133, Italy
| | - Paul W King
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401, USA
| | - Gianfranco Gilardi
- Department of Life Sciences and Systems Biology, University of Torino, Torino 10133, Italy
| | - Francesca Valetti
- Department of Life Sciences and Systems Biology, University of Torino, Torino 10133, Italy.
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Chen HYT, Livraghi S, Giamello E, Pacchioni G. Mechanism of the Cyclo-Oligomerisation of C2H2on Anatase TiO2(101) and (001) Surfaces and Their Reduction: An Electron Paramagnetic Resonance and Density Functional Theory Study. Chempluschem 2015; 81:64-72. [DOI: 10.1002/cplu.201500383] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Indexed: 11/10/2022]
Affiliation(s)
- Hsin-Yi Tiffany Chen
- Dipartimento di Scienza dei Materiali; Università di Milano-Bicocca; via Cozzi 55 20125 Milano Italy
| | - Stefano Livraghi
- Dipartimento di Chimica and NIS; Università di Torino; Via P. Giuria 7 10125 Torino Italy
| | - Elio Giamello
- Dipartimento di Chimica and NIS; Università di Torino; Via P. Giuria 7 10125 Torino Italy
| | - Gianfranco Pacchioni
- Dipartimento di Scienza dei Materiali; Università di Milano-Bicocca; via Cozzi 55 20125 Milano Italy
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35
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Morra E, Maurelli S, Chiesa M, Giamello E. Rational Design of Engineered Multifunctional Heterogeneous Catalysts. The Role of Advanced EPR Techniques. Top Catal 2015. [DOI: 10.1007/s11244-015-0418-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Morra E, Giamello E, Van Doorslaer S, Antinucci G, D'Amore M, Busico V, Chiesa M. Probing the Coordinative Unsaturation and Local Environment of Ti3+ Sites in an Activated High-Yield Ziegler-Natta Catalyst. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201412052] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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37
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Morra E, Giamello E, Van Doorslaer S, Antinucci G, D'Amore M, Busico V, Chiesa M. Probing the Coordinative Unsaturation and Local Environment of Ti3+ Sites in an Activated High-Yield Ziegler-Natta Catalyst. Angew Chem Int Ed Engl 2015; 54:4857-60. [DOI: 10.1002/anie.201412052] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Revised: 01/30/2015] [Indexed: 11/12/2022]
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Biedrzycki JJ, Livraghi S, Corazzari I, Mino L, Spoto G, Giamello E. On the redox mechanism operating along C2H2 self-assembly at the surface of TiO2. Langmuir 2015; 31:569-577. [PMID: 25514364 DOI: 10.1021/la504290d] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The interaction of acetylene with the TiO2 surface at room temperature entails a complex set of self-assembly reactions with the formation of products having relatively high molecular weight. In a previous paper by some of us (Jain, S. M.; et al. J. Mater. Chem. A 2014, 2, 12247-12254), the C2H2-TiO2 reaction has been monitored, essentially by Fourier transform infrared spectroscopy, at the surface of P25 (a mixture of anatase and rutile, typical benchmark material in the field of photocatalysis) in order to elucidate the nature of the products of this surface reaction. In the present paper, the same process was followed, for the first time, using electron paramagnetic resonance (EPR) and monitoring by the thermogravimetric analysis the weight loss of the material upon heating in order to further investigate the complex mechanism of the surface reaction. This was done using pure anatase and comparing the EPR results with those concerning both rutile and P25. The self-assembly mechanism occurring at the interface is accompanied by the formation of EPR visible Ti(3+) centers due to electrons injection in the TiO2 substrate. This finding clarifies that at least one of the reaction channels of this complex process (namely, the formation of polycyclic aromatic hydrocarbons) is based on the heterolytic dissociative chemisorption of acetylene, followed by a redox interaction between the adsorbate and the solid, which allows the creation of the building blocks necessary to assemble polyaromatic molecules.
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Affiliation(s)
- Jakub Jan Biedrzycki
- Dipartimento di Chimica, Università di Torino and NIS, Centre for Nanostructured Interfaces and Surface , Via P. Giuria 7, I - 10125 Torino, Italy
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Morra E, Giamello E, Chiesa M. Probing the redox chemistry of titanium silicalite-1: formation of tetrahedral Ti3+ centers by reaction with triethylaluminum. Chemistry 2014; 20:7381-8. [PMID: 24824439 DOI: 10.1002/chem.201304139] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Revised: 11/21/2013] [Indexed: 11/10/2022]
Abstract
Transition-metal ions with open-shell configurations hold promise in the development of novel coordination chemistry and potentially unprecedented redox catalysis. Framework-substituted Ti(3+) ions with tetrahedral coordination are generated by reductive activation of titanium silicalite-1 with triethylaluminum, an indispensable co-catalyst for heterogeneous Ziegler-Natta polymerization catalysts. Continuous-wave and pulse electron paramagnetic resonance methods are applied to unravel details on the local environment of the reduced transition metal-ions, which are shown to be part of the silica framework by detection of (29)Si hyperfine interactions. The chemical accessibility of the reduced sites is probed using ammonia as probe molecule. Evidence is found for the coordination of a single ammonia molecule. Comparison to similar systems, such as TiAlPO-5, reveals clear differences in the coordination chemistry of the reduced Ti sites in the two solids, which may be understood considering the different electronic properties of the solid frameworks.
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Affiliation(s)
- Elena Morra
- Department of Chemistry, University of Torino, Via Giuria, 7, 10125 Torino (Italy), Fax: (+39) 0116707855; Dutch Polymer Institute (DPI), P.O. Box 902, 5600 AX Eindhoven (The Netherlands)
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40
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Gionco C, Paganini MC, Giamello E, Burgess R, Di Valentin C, Pacchioni G. Cerium-Doped Zirconium Dioxide, a Visible-Light-Sensitive Photoactive Material of Third Generation. J Phys Chem Lett 2014; 5:447-451. [PMID: 26276590 DOI: 10.1021/jz402731s] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The dispersion of small amounts of Ce(4+) ions in the bulk of ZrO2 leads to a photoactive material sensitive to visible light. This is shown by monitoring with EPR the formation and the reactivity of photogenerated (λ > 420 nm) charge carriers. The effect, as confirmed by DFT calculations, is due to the presence in the solid of empty 4f Ce states at the mid gap, which act as intermediate levels in a double excitation mechanism. This solid can be considered an example of a third-generation photoactive material.
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Affiliation(s)
- Chiara Gionco
- †Dipartimento di Chimica, Università di Torino and NIS, Nanostructured Interfaces and Surfaces, Via P. Giuria 7, 10125 Torino, Italy
| | - Maria C Paganini
- †Dipartimento di Chimica, Università di Torino and NIS, Nanostructured Interfaces and Surfaces, Via P. Giuria 7, 10125 Torino, Italy
| | - Elio Giamello
- †Dipartimento di Chimica, Università di Torino and NIS, Nanostructured Interfaces and Surfaces, Via P. Giuria 7, 10125 Torino, Italy
| | - Robertson Burgess
- ‡Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, Via R. Cozzi, 55, 20125, Milano, Italy
| | - Cristiana Di Valentin
- ‡Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, Via R. Cozzi, 55, 20125, Milano, Italy
| | - Gianfranco Pacchioni
- ‡Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, Via R. Cozzi, 55, 20125, Milano, Italy
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Gionco C, Giamello E, Mino L, Paganini MC. The interaction of oxygen with the surface of CeO2–TiO2 mixed systems: an example of fully reversible surface-to-molecule electron transfer. Phys Chem Chem Phys 2014; 16:21438-45. [DOI: 10.1039/c4cp03195d] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
CeO2–TiO2 mixed oxides showed an unusual and fully reversible interaction with molecular oxygen similar to that of natural and synthetic oxygen carriers.
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Affiliation(s)
- Chiara Gionco
- Dipartimento di Chimica and NIS
- Università degli Studi di Torino
- Torino, Italy
| | - Elio Giamello
- Dipartimento di Chimica and NIS
- Università degli Studi di Torino
- Torino, Italy
| | - Lorenzo Mino
- Dipartimento di Chimica and NIS
- Università degli Studi di Torino
- Torino, Italy
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42
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Gionco C, Battiato A, Vittone E, Paganini MC, Giamello E. Structural and spectroscopic properties of high temperature prepared ZrO2–TiO2 mixed oxides. J SOLID STATE CHEM 2013. [DOI: 10.1016/j.jssc.2013.02.040] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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43
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Chiesa M, Paganini MC, Livraghi S, Giamello E. Charge trapping in TiO2 polymorphs as seen by Electron Paramagnetic Resonance spectroscopy. Phys Chem Chem Phys 2013; 15:9435-47. [DOI: 10.1039/c3cp50658d] [Citation(s) in RCA: 163] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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44
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Maurelli S, Chiesa M, Giamello E, Leithall RM, Raja R. A HYSCORE investigation of bimetallic titanium–vanadium microporous catalysts: elucidating the nature of the active sites. Chem Commun (Camb) 2012; 48:8700-2. [DOI: 10.1039/c2cc33997h] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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45
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Corazzari I, Livraghi S, Ferrero S, Giamello E, Fubini B, Fenoglio I. Inactivation of TiO2 nano-powders for the preparation of photo-stable sunscreens via carbon-based surface modification. ACTA ACUST UNITED AC 2012. [DOI: 10.1039/c2jm32876c] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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46
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Livraghi S, Maurelli S, Paganini MC, Chiesa M, Giamello E. Probing the Local Environment of Ti3+ Ions in TiO2 (Rutile) by 17O HYSCORE. Angew Chem Int Ed Engl 2011. [DOI: 10.1002/ange.201100531] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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47
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Livraghi S, Maurelli S, Paganini MC, Chiesa M, Giamello E. Probing the Local Environment of Ti3+ Ions in TiO2 (Rutile) by 17O HYSCORE. Angew Chem Int Ed Engl 2011; 50:8038-40. [DOI: 10.1002/anie.201100531] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2011] [Indexed: 11/11/2022]
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48
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Maurelli S, Livraghi S, Chiesa M, Giamello E, Van Doorslaer S, Di Valentin C, Pacchioni G. Hydration Structure of the Ti(III) Cation as Revealed by Pulse EPR and DFT Studies: New Insights into a Textbook Case. Inorg Chem 2011; 50:2385-94. [DOI: 10.1021/ic1021802] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Sara Maurelli
- Dipartimento di Chimica IFM, Università di Torino and NIS, Nanostructured Interfaces and Surfaces Centre of Excellence, Via P. Giuria 7, I-10125 Torino, Italy
| | - Stefano Livraghi
- Dipartimento di Chimica IFM, Università di Torino and NIS, Nanostructured Interfaces and Surfaces Centre of Excellence, Via P. Giuria 7, I-10125 Torino, Italy
| | - Mario Chiesa
- Dipartimento di Chimica IFM, Università di Torino and NIS, Nanostructured Interfaces and Surfaces Centre of Excellence, Via P. Giuria 7, I-10125 Torino, Italy
| | - Elio Giamello
- Dipartimento di Chimica IFM, Università di Torino and NIS, Nanostructured Interfaces and Surfaces Centre of Excellence, Via P. Giuria 7, I-10125 Torino, Italy
| | - Sabine Van Doorslaer
- University of Antwerp, Department of Physics, Universiteitsplein 1, B-2610 Wilrijk-Antwerp, Belgium
| | - Cristiana Di Valentin
- Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, Via R. Cozzi, 53-20125, Milano, Italy
| | - Gianfranco Pacchioni
- Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, Via R. Cozzi, 53-20125, Milano, Italy
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49
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Dozzi MV, Livraghi S, Giamello E, Selli E. Photocatalytic activity of S- and F-doped TiO2in formic acid mineralization. Photochem Photobiol Sci 2011; 10:343-9. [DOI: 10.1039/c0pp00182a] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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50
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Czoska AM, Livraghi S, Paganini MC, Giamello E, Di Valentin C, Pacchioni G. The nitrogen–boron paramagnetic center in visible light sensitized N–B co-doped TiO2. Experimental and theoretical characterization. Phys Chem Chem Phys 2011; 13:136-43. [DOI: 10.1039/c0cp00143k] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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