1
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Schwab T, Razouq H, Aicher K, Zickler GA, Diwald O. Conversion of MgO nanocrystal surfaces into ceramic interfaces: Exsolution of BaO as photoluminescent interface probes. JOURNAL OF THE AMERICAN CERAMIC SOCIETY. AMERICAN CERAMIC SOCIETY 2023; 106:897-912. [PMID: 37063706 PMCID: PMC10092509 DOI: 10.1111/jace.18833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 09/09/2022] [Accepted: 09/24/2022] [Indexed: 06/19/2023]
Abstract
Ion exsolution can be instrumental to engineer intergranular regions inside ceramic microstructures. BaO admixtures that were trapped inside nanometer-sized MgO grains during gas phase synthesis undergo annealing-induced exsolution to generate photoluminescent surface and interface structures. During their segregation from the bulk into the grain interfaces, the BaO admixtures impact grain coarsening and powder densification, effects that were compared for the first time using an integrated characterization approach. For the characterization of the different stages the materials adopt between powder synthesis and compact annealing, spectroscopy measurements (UV-Vis diffuse reflectance, cathodo- and photoluminescence [PL]) were complemented by an in-depth structure characterization (density measurements, X-ray diffraction [XRD], and electron microscopy). Depending on the Ba2+ concentration, isolated impurity ions either become part of low-coordinated surface structures of the MgO grains where they give rise to a characteristic bright PL emission profile around λ = 500 nm, or they aggregate to form nanocrystalline BaO segregates at the inner pore surfaces to produce an emission feature centered at λ = 460 nm. Both types of PL emission sites exhibit O2 gas adsorption-dependent PL emission properties that are reversible with respect to its pressure. The here-reported distribution of BaO segregates between the intergranular region and the free pore surfaces inside the MgO-based compacts underlines that solid-based exsolution strategies are well suited to stabilize nanometer-sized segregates of metal oxides that otherwise would coalesce and grow in size beyond the nanoscale.
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Affiliation(s)
- Thomas Schwab
- Department of Chemistry and Physics of MaterialsParis‐Lodron Universität SalzburgSalzburgAustria
| | - Hasan Razouq
- Department of Chemistry and Physics of MaterialsParis‐Lodron Universität SalzburgSalzburgAustria
| | - Korbinian Aicher
- Department of Chemistry and Physics of MaterialsParis‐Lodron Universität SalzburgSalzburgAustria
| | - Gregor A. Zickler
- Department of Chemistry and Physics of MaterialsParis‐Lodron Universität SalzburgSalzburgAustria
| | - Oliver Diwald
- Department of Chemistry and Physics of MaterialsParis‐Lodron Universität SalzburgSalzburgAustria
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2
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Schwab T, Thomele D, Aicher K, Dunlop JWC, McKenna K, Diwald O. Rubbing Powders: Direct Spectroscopic Observation of Triboinduced Oxygen Radical Formation in MgO Nanocube Ensembles. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2021; 125:22239-22248. [PMID: 34676020 PMCID: PMC8521521 DOI: 10.1021/acs.jpcc.1c05898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 09/14/2021] [Indexed: 06/13/2023]
Abstract
Powder compaction-induced surface chemistry in metal oxide nanocrystal ensembles is important for very diverse fields such as triboelectrics, tribocatalysts, surface abrasion, and cold sintering of ceramics. Using a range of spectroscopic techniques, we show that MgO nanocube powder compaction with uniaxial pressures that can be achieved by gentle manual rubbing or pressing (p ≥ 5 MPa) excites energetic electron-hole pairs and generates oxygen radicals at interfacial defect structures. While the identification of paramagnetic O- radicals and their adsorption complexes with O2 point to the emergence of hole centers, triboemitted electrons become scavenged by molecular oxygen to convert into adsorbed superoxide anions O2 - as measured by electron paramagnetic resonance (EPR). By means of complementary UV-photoexcitation experiments, we found that photon energies in the range between 3 and 6 eV produce essentially the same EPR spectroscopic fingerprints and optical absorption features. To provide insights into this effect, we performed density functional theory calculations to explore the energetics of charge separation involving the ionization of low-coordinated anions and surface-adsorbed O2 - radicals at points of contact. For all selected configurations, charge transfer is not spontaneous but requires an additional driving force. We propose that a plausible mechanism for oxygen radical formation is the generation of significant surface potential differences at points of contact under loading as a result of the highly inhomogeneous elastic deformations coupled with the flexoelectric effect.
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Affiliation(s)
- Thomas Schwab
- Department
of Chemistry and Physics of Materials, Paris-Lodron
University Salzburg, Jakob-Haringer-Straße 2a, A-5020 Salzburg, Austria
| | - Daniel Thomele
- Department
of Chemistry and Physics of Materials, Paris-Lodron
University Salzburg, Jakob-Haringer-Straße 2a, A-5020 Salzburg, Austria
| | - Korbinian Aicher
- Department
of Chemistry and Physics of Materials, Paris-Lodron
University Salzburg, Jakob-Haringer-Straße 2a, A-5020 Salzburg, Austria
| | - John W. C. Dunlop
- Department
of Chemistry and Physics of Materials, Paris-Lodron
University Salzburg, Jakob-Haringer-Straße 2a, A-5020 Salzburg, Austria
| | - Keith McKenna
- Department
of Physics, University of York, Heslington, YO10 5DD York, U.K.
| | - Oliver Diwald
- Department
of Chemistry and Physics of Materials, Paris-Lodron
University Salzburg, Jakob-Haringer-Straße 2a, A-5020 Salzburg, Austria
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3
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Zwijnenburg MA. The effect of particle size on the optical and electronic properties of magnesium oxide nanoparticles. Phys Chem Chem Phys 2021; 23:21579-21590. [PMID: 34553204 DOI: 10.1039/d1cp02683f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The quasiparticle states, fundamental gaps, optical gaps, exciton binding energies and UV-vis spectra for a series of cuboidal nanoparticles of the prototypical oxide magnesium oxide (MgO), the largest of which has 216 atoms and edges of 1 nm, were predicted using many-body perturbation theory (evGW-BSE). The evolution of the properties with the particle size was explicitly studied. It was found that, while the highest occupied and lowest unoccupied quasiparticle states and fundamental gap change with the particle size, the optical gap remains essentially fixed for all but the smallest nanoparticles, in line with what was previously observed experimentally. The explanation for these observations is demonstrated to be that, while the optical gap is associated with an exciton that is highly localised around the particle's corner atoms, the highest occupied and lowest unoccupied quasiparticle states, while primarily localised on the oxygen corner atoms (hole) and magnesium corner atoms (electron), show significant delocalisation along the edges. The strong localisation of the exciton associated with the optical gap on the corner atoms is argued to also explain why the nanoparticles have much smaller optical gaps and red-shifted spectra compared to bulk MgO. Finally, it is discussed how this non-quantum confinement behaviour, where the properties of the nanoparticles arise from surface defects rather than differences in localisation of quasiparticle or exciton states, appears typical of alkaline earth oxide nanoparticles, and that the true optical gap of bulk crystals of such materials is also probably the result of surface defects, even if unobservable experimentally.
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Affiliation(s)
- Martijn A Zwijnenburg
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, UK.
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4
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Singh JP, Singh V, Sharma A, Pandey G, Chae KH, Lee S. Approaches to synthesize MgO nanostructures for diverse applications. Heliyon 2020; 6:e04882. [PMID: 33024853 PMCID: PMC7527648 DOI: 10.1016/j.heliyon.2020.e04882] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Revised: 02/26/2020] [Accepted: 09/07/2020] [Indexed: 10/27/2022] Open
Abstract
Magnesium oxide remained interesting from long time for several important phenomena like; defect induced magnetism, spin electron reflectivity, broad laser emission etc. Moreover, nanostructures of this material exhibited suitability for different kinds of applications ranging from wastewater treatment to spintronics depending upon their shape and size. In this way, researchers had grown nanostructures in the form of nanoparticles, thin films, nanotubes, nanowalls, nanobelts. Though nanoparticles and thin films are well known form of nanostructures and wide variety of synthesis approaches are available, however, limited methodology for other nanostructures are available. In order to grow these nanostructures in an optimized way an understanding of these methods is essential. Thus, this review article depicts an overview of various approaches for design of different kinds of nanostructures.
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Affiliation(s)
- Jitendra Pal Singh
- Pohang Accelerator Laboratory, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
| | - Varsha Singh
- Advanced Analysis Center, Korea Institute of Science and Technology, Seoul, 02792, Republic of Korea
| | - Aditya Sharma
- Department of Physics, Manav Rachna University, Faridabad, Haryana, 121004, India
| | - Ganesh Pandey
- University of Petroleum & Energy Studies (UPES), Dehradun, Uttarakhand, 248007, India
- Gus Global Services ( India) Private Limited, Gurugram, Haryana, 122011, India
| | - Keun Hwa Chae
- Advanced Analysis Center, Korea Institute of Science and Technology, Seoul, 02792, Republic of Korea
| | - Sangsul Lee
- Pohang Accelerator Laboratory, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
- Xavisoptics Ltd., Pohang 37673, Republic of Korea
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5
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Suresh M, Jeevanandam J, Chan YS, Danquah MK, Kalaiarasi JMV. Opportunities for Metal Oxide Nanoparticles as a Potential Mosquitocide. BIONANOSCIENCE 2019. [DOI: 10.1007/s12668-019-00703-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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6
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Jeevanandam J, Chan YS, Danquah MK, Law MC. Cytotoxicity Analysis of Morphologically Different Sol-Gel-Synthesized MgO Nanoparticles and Their In Vitro Insulin Resistance Reversal Ability in Adipose cells. Appl Biochem Biotechnol 2019; 190:1385-1410. [PMID: 31776944 DOI: 10.1007/s12010-019-03166-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Accepted: 10/23/2019] [Indexed: 12/19/2022]
Abstract
Insulin resistance is one of the major factors that leads to type 2 diabetes. Although insulin therapies have been shown to overcome insulin resistance, overweight and hypoglycemia are still observed in most cases. The disadvantages of insulin therapies have driven the interest in developing novel curative agents with enhanced insulin resistance reversibility. Magnesium deficiency has also been recognized as a common problem which leads to insulin resistance in both type 1 and 2 diabetes. Oxide nanoparticles demonstrate highly tunable physicochemical properties that can be exploited by engineers to develop unique oxide nanoparticles for tailored applications. Magnesium supplements for diabetic cells have been reported to increase the insulin resistance reversibility. Hence, it is hypothesized that magnesium oxide (MgO) nanoparticles could be molecularly engineered to offer enhanced therapeutic efficacy in reversing insulin resistance. In the present work, morphologically different MgO nanoparticles were synthesized and evaluated for biophysical characteristics, biocompatibility, cytotoxicity, and insulin resistance reversibility. MTT assay revealed that hexagonally shaped MgO nanoparticles are less toxic to 3T3-L1 adipose cells (diabetic) compared with spherically and rod-shaped MgO nanoparticles. MTT assays using VERO cells (normal, non-diabetic) showed that 400 μg/ml of hexagonal MgO nanoparticles were less toxic to both diabetic and non-diabetic cells. DNS glucose assay and western blot showed that hexagonally shaped MgO nanoparticles had reversed 29.5% of insulin resistance whilst fluorescence microscopy studies indicated that the insulin resistance reversal is due to the activation of intracellular enzymes. The probable mechanism for MgO nanoparticles to induce cytotoxic effect and insulin resistance reversal is discussed.
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Affiliation(s)
- Jaison Jeevanandam
- Department of Chemical Engineering, Faculty of Engineering and Science, Curtin University, CDT 250, 98009, Miri, Sarawak, Malaysia
| | - Yen San Chan
- Department of Chemical Engineering, Faculty of Engineering and Science, Curtin University, CDT 250, 98009, Miri, Sarawak, Malaysia.
| | - Michael K Danquah
- Chemical Engineering Department, University of Tennessee, Chattanooga, TN, 37403, USA
| | - Ming Chiat Law
- Department of Mechanical Engineering, Faculty of Engineering and Science, Curtin University, CDT 250, 98009, Miri, Sarawak, Malaysia
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7
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Thomele D, Gheisi AR, Niedermaier M, Elsässer MS, Bernardi J, Grönbeck H, Diwald O. Thin water films and particle morphology evolution in nanocrystalline MgO. JOURNAL OF THE AMERICAN CERAMIC SOCIETY. AMERICAN CERAMIC SOCIETY 2018; 101:4994-5003. [PMID: 30333631 PMCID: PMC6175089 DOI: 10.1111/jace.15775] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 05/05/2018] [Indexed: 05/29/2023]
Abstract
A key question in the field of ceramics and catalysis is how and to what extent residual water in the reactive environment of a metal oxide particle powder affects particle coarsening and morphology. With X-ray Diffraction (XRD) and Transmission Electron Microscopy (TEM), we investigated annealing-induced morphology changes on powders of MgO nanocubes in different gaseous H2O environments. The use of such a model system for particle powders enabled us to describe how adsorbed water that originates from short exposure to air determines the evolution of MgO grain size, morphology, and microstructure. While cubic nanoparticles with a predominant abundance of (100) surface planes retain their shape after annealing to T = 1173 K under continuous pumping with a base pressure of water p(H2O) = 10-5 mbar, higher water partial pressures promote mass transport on the surfaces and across interfaces of such particle systems. This leads to substantial growth and intergrowth of particles and simultaneously favors the formation of step edges and shallow protrusions on terraces. The mass transfer is promoted by thin films of water providing a two-dimensional solvent for Mg2+ ion hydration. In addition, we obtained direct evidence for hydroxylation-induced stabilization of (110) faces and step edges of the grain surfaces.
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Affiliation(s)
- Daniel Thomele
- Department of Chemistry and Physics of MaterialsParis‐Lodron University SalzburgSalzburgAustria
| | - Amir R. Gheisi
- Institute of Particle TechnologyFriedrich‐Alexander Universität Erlangen‐NürnbergErlangenGermany
| | - Matthias Niedermaier
- Department of Chemistry and Physics of MaterialsParis‐Lodron University SalzburgSalzburgAustria
| | - Michael S. Elsässer
- Department of Chemistry and Physics of MaterialsParis‐Lodron University SalzburgSalzburgAustria
| | - Johannes Bernardi
- University Service Center for Transmission Electron MicroscopyTechnische Universität WienViennaAustria
| | - Henrik Grönbeck
- Department of Physics and Competence Centre for CatalysisChalmers University of TechnologyGothenburgSweden
| | - Oliver Diwald
- Department of Chemistry and Physics of MaterialsParis‐Lodron University SalzburgSalzburgAustria
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8
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Zhang L, Huang TJ, Gong H. Remarkable improvement in supercapacitor performance by sulfur introduction during a one-step synthesis of nickel hydroxide. Phys Chem Chem Phys 2017; 19:10462-10469. [PMID: 28382343 DOI: 10.1039/c7cp01234a] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Composition control by introducing sulfur during a one-step synthesis of nickel hydroxide is successfully achieved using our unique design. And it has been demonstrated to be an effective strategy by increasing the specific capacitance by more than 40%. A systematic study reveals that as the sulfur (S) to oxygen (O) ratio is increased, the specific capacitance first increases and then decreases. At a S to O ratio of approximately one, the composite outperforms other ratios, delivering a remarkable capacitance of 2801 F g-1 at 2 A g-1. More importantly from the customer point of view and viability for practical applications, a high specific capacitance of 457 F g-1 is achieved per total weight of the active material plus substrate. The energy density per weight of the active materials reaches a high value of 61 Wh kg-1. The energy density per total weight of the active material and substrate reached a very high value of 34 Wh kg-1. A detailed study on the role of S is performed experimentally and theoretically. The results reveal for the first time that sulfur itself does not contribute to the increase in specific performance, and the significant improvements in capacitance and energy density can be attributed to sulfur induced refinement in clusters and morphology.
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Affiliation(s)
- Liuyang Zhang
- Department of Materials Science and Engineering, National University of Singapore, Singapore 117576, Singapore.
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9
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Thomele D, Bourret GR, Bernardi J, Bockstedte M, Diwald O. Hydroxylation Induced Alignment of Metal Oxide Nanocubes. Angew Chem Int Ed Engl 2016; 56:1407-1410. [PMID: 28005313 DOI: 10.1002/anie.201608538] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Revised: 10/27/2016] [Indexed: 01/03/2023]
Abstract
Water vapor is ubiquitous under ambient conditions and may alter the shape of nanoparticles. How to utilize water adsorption for nanomaterial functionality and structure formation, however, is a yet unexplored field. Herein, we report the use of water vapor to induce the self-organization of MgO nanocubes into regularly staggered one-dimensional structures. This transformation evolves via an initial alignment of the MgO cubes, the formation of intermediate elongated Mg(OH)2 structures, and their reconversion into MgO cubes arranged in staggered structures. Ab initio DFT modelling identifies surface-energy changes associated with the cube surface hydration and hydroxylation to promote the uncommon staggered stacked assembly of the cubes. This first observation of metal oxide nanoparticle self-organization occurring outside a bulk solution may pave novel routes for inducing texture in ceramics and represents a great test-bed for new surface-science concepts.
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Affiliation(s)
- Daniel Thomele
- Department of Chemistry and Physics of Materials, Paris Lodron University of Salzburg, Hellbrunnerstrasse 34/III, 5020, Salzburg, Austria
| | - Gilles R Bourret
- Department of Chemistry and Physics of Materials, Paris Lodron University of Salzburg, Hellbrunnerstrasse 34/III, 5020, Salzburg, Austria
| | - Johannes Bernardi
- University Service Center for Transmission Electron Microscopy, Vienna University of Technology, Wiedner Hauptstrasse 8-10, 1040, Vienna, Austria
| | - Michel Bockstedte
- Department of Chemistry and Physics of Materials, Paris Lodron University of Salzburg, Hellbrunnerstrasse 34/III, 5020, Salzburg, Austria.,Lehrstuhl für Theoretische Festkörperphysik, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstrasse 7B2, 91058, Erlangen, Germany
| | - Oliver Diwald
- Department of Chemistry and Physics of Materials, Paris Lodron University of Salzburg, Hellbrunnerstrasse 34/III, 5020, Salzburg, Austria
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10
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Thomele D, Bourret GR, Bernardi J, Bockstedte M, Diwald O. Organisation von Metalloxid‐Nanowürfeln durch Hydroxylierung. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201608538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Daniel Thomele
- Fachbereich Chemie und Physik der Materialien Paris Lodron Universität Salzburg Hellbrunnerstraße 34/III 5020 Salzburg Österreich
| | - Gilles R. Bourret
- Fachbereich Chemie und Physik der Materialien Paris Lodron Universität Salzburg Hellbrunnerstraße 34/III 5020 Salzburg Österreich
| | - Johannes Bernardi
- Universitätsservicezentrum für Transmissionselektronenmikroskopie TU Wien Wiedner Hauptstraße 8–10 1040 Wien Österreich
| | - Michel Bockstedte
- Fachbereich Chemie und Physik der Materialien Paris Lodron Universität Salzburg Hellbrunnerstraße 34/III 5020 Salzburg Österreich
- Lehrstuhl für Theoretische Festkörperphysik Friedrich-Alexander-Universität Erlangen-Nürnberg Staudtstraße 7B2 91058 Erlangen Deutschland
| | - Oliver Diwald
- Fachbereich Chemie und Physik der Materialien Paris Lodron Universität Salzburg Hellbrunnerstraße 34/III 5020 Salzburg Österreich
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11
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Zheng Y, Zhang X, Bai Z, Zhang Z. Characterization of the surface properties of MgO using paper spray mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2016; 30 Suppl 1:217-225. [PMID: 27539441 DOI: 10.1002/rcm.7635] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
RATIONALE Significant advances have been made in the preparation of different morphologies of magnesium oxide (MgO), but the relationship between MgO morphology and its interactions with therapeutic drugs is rarely studied. Herein, we investigated the interactions between different morphologies of MgO and therapeutic drugs using paper spray mass spectrometry. METHODS Different morphologies of MgO including trapezoidal, needle-like, flower-like and nest-like structures were prepared through a facile precipitation method. The as-obtained MgO particles were then coated onto the surface of filter paper via vacuum filtration strategy. The coated papers with different morphologies of MgO were used as the substrates for paper spray mass spectrometry to explore the interactions between different MgO and therapeutic drugs. RESULTS Through investigating the interactions between different morphologies of MgO coated papers and therapeutic drugs, it demonstrated that, in contrast to the trapezoidal, needle-like and nest-like MgO coated papers, different drugs in dried blood spots (DBS) were more favourably eluted off from the paper coated with flower-like MgO due to its weaker surface basicity. Also, the signal intensities of different drugs during paper spray were highly dependent on their elution behaviours. CONCLUSIONS Paper spray mass spectrometry (MS) provides an avenue to elaborate the surface properties of MgO with different structures. The surface basicity of MgO played a crucial role in determining the elution behaviours of therapeutic drugs in DBS, and a more favourable elution behaviour tended to result in a higher MS signal. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Yajun Zheng
- School of Chemistry and Chemical Engineering, Xi'an Shiyou University, Xi'an, 710065, China
| | - Xiaoling Zhang
- School of Chemistry and Chemical Engineering, Xi'an Shiyou University, Xi'an, 710065, China
| | - Zongquan Bai
- School of Chemistry and Chemical Engineering, Xi'an Shiyou University, Xi'an, 710065, China
| | - Zhiping Zhang
- School of Chemistry and Chemical Engineering, Xi'an Shiyou University, Xi'an, 710065, China
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12
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Schneider J, Franke M, Gurrath M, Röckert M, Berger T, Bernardi J, Meyer B, Steinrück HP, Lytken O, Diwald O. Porphyrin Metalation at MgO Surfaces: A Spectroscopic and Quantum Mechanical Study on Complementary Model Systems. Chemistry 2015; 22:1744-9. [PMID: 26682774 DOI: 10.1002/chem.201503661] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Indexed: 11/05/2022]
Abstract
We show that both single-crystalline and nanostructured MgO surfaces convert free-base tetraphenyl porphyrin (2HTPP) into magnesium tetraphenyl porphyrin (MgTPP) at room temperature. The reaction can be viewed as an ion exchange between the two aminic protons of the 2HTPP molecule with a Mg(2+) ion from the surface. The driving force for the reaction is the strong stability of the formed hydroxyl groups along the steps and at defects on the MgO surface. We have used an integrated characterization approach that includes UV/Vis diffuse reflectance measurements on nanostructured powders, X-ray photoelectron spectroscopic investigation of atomically clean MgO(100) single-crystalline thin films, and density functional theory (DFT) calculations on model systems. The DFT calculations demonstrate that MgTPP formation is strongly exothermic at the corners, edges and steps, but slightly endothermic on terrace sites. This agrees well with the UV/Vis diffuse reflectance, which upon adsorption of 2HTPP shows a decrease in the absorption band associated with corner and edge sites on MgO nanocube powders.
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Affiliation(s)
- Johannes Schneider
- Department of Chemistry & Physics of Materials, Paris-Lodron University Salzburg, Salzburg, Austria
| | - Matthias Franke
- Institute of Physical Chemistry II, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany
| | - Martin Gurrath
- Interdisciplinary Center for Molecular Materials (ICMM) and Computer-Chemistry-Center (CCC), Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany
| | - Michael Röckert
- Institute of Physical Chemistry II, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany
| | - Thomas Berger
- Department of Chemistry & Physics of Materials, Paris-Lodron University Salzburg, Salzburg, Austria
| | - Johannes Bernardi
- University Service Centre for Transmission Electron Microscopy, Vienna University of Technology, Vienna, Austria
| | - Bernd Meyer
- Interdisciplinary Center for Molecular Materials (ICMM) and Computer-Chemistry-Center (CCC), Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany.
| | - Hans-Peter Steinrück
- Institute of Physical Chemistry II, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany
| | - Ole Lytken
- Institute of Physical Chemistry II, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany.
| | - Oliver Diwald
- Department of Chemistry & Physics of Materials, Paris-Lodron University Salzburg, Salzburg, Austria.
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13
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Patel MK, Ali MA, Krishnan S, Agrawal VV, Al Kheraif AA, Fouad H, Ansari Z, Ansari SG, Malhotra BD. A Label-Free Photoluminescence Genosensor Using Nanostructured Magnesium Oxide for Cholera Detection. Sci Rep 2015; 5:17384. [PMID: 26611737 PMCID: PMC4661725 DOI: 10.1038/srep17384] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Accepted: 10/29/2015] [Indexed: 11/20/2022] Open
Abstract
Nanomaterial-based photoluminescence (PL) diagnostic devices offer fast and highly sensitive detection of pesticides, DNA, and toxic agents. Here we report a label-free PL genosensor for sensitive detection of Vibrio cholerae that is based on a DNA hybridization strategy utilizing nanostructured magnesium oxide (nMgO; size >30 nm) particles. The morphology and size of the synthesized nMgO were determined by transmission electron microscopic (TEM) studies. The probe DNA (pDNA) was conjugated with nMgO and characterized by X-ray photoelectron and Fourier transform infrared spectroscopic techniques. The target complementary genomic DNA (cDNA) isolated from clinical samples of V. cholerae was subjected to DNA hybridization studies using the pDNA-nMgO complex and detection of the cDNA was accomplished by measuring changes in PL intensity. The PL peak intensity measured at 700 nm (red emission) increases with the increase in cDNA concentration. A linear range of response in the developed PL genosensor was observed from 100 to 500 ng/μL with a sensitivity of 1.306 emi/ng, detection limit of 3.133 ng/μL and a regression coefficient (R(2)) of 0.987. These results show that this ultrasensitive PL genosensor has the potential for applications in the clinical diagnosis of cholera.
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Affiliation(s)
- Manoj Kumar Patel
- Biomedical Instrumentation Section, CSIR-National Physical Laboratory, Dr. K. S. Krishnan Marg, New Delhi 110012, India
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi 110025, India
- Department of Chemistry, College of Arts and Sciences, Oklahoma State University, Stillwater, Oklahoma 74078, United States of America
| | - Md. Azahar Ali
- Biomedical Instrumentation Section, CSIR-National Physical Laboratory, Dr. K. S. Krishnan Marg, New Delhi 110012, India
- Department of Electrical and Computer Engineering, Iowa State University, Ames, IA 50011, United States of America
| | - Sadagopan Krishnan
- Department of Chemistry, College of Arts and Sciences, Oklahoma State University, Stillwater, Oklahoma 74078, United States of America
| | - Ved Varun Agrawal
- Biomedical Instrumentation Section, CSIR-National Physical Laboratory, Dr. K. S. Krishnan Marg, New Delhi 110012, India
| | - AbdulAziz A. Al Kheraif
- Dental Biomaterials Research Chair, Dental Health Department, College of Applied Medical Science, King Saud University, Riyadh, 11437 Saudi Arabia
| | - H. Fouad
- Dental Biomaterials Research Chair, Dental Health Department, College of Applied Medical Science, King Saud University, Riyadh, 11437 Saudi Arabia
- Biomedical Engineering Department, Faculty of Engineering, Helwan University, 11792, Egypt
| | - Z.A. Ansari
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi 110025, India
| | - S. G. Ansari
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi 110025, India
| | - Bansi D. Malhotra
- Department of Biotechnology, Delhi Technological University, Shahabad Daulatpur, Main Bawana Road, Delhi 110042, India
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14
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Wobbe MCC, Zwijnenburg MA. Chemical trends in the optical properties of rocksalt nanoparticles. Phys Chem Chem Phys 2015; 17:28892-900. [PMID: 26456027 DOI: 10.1039/c5cp04851f] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The nature and magnitude of the optical gaps of rocksalt alkaline earth (MgO, CaO, SrO, MgS, MgSe) and transition metal chalcogenide (CdO, PbS) nanoparticles are studied using time-dependent density functional theory (TD-DFT) calculations on (MX)32 nanoparticles. We demonstrate, just as we previously showed for MgO, that TD-DFT calculations on rocksalt nanoparticles require the use of hybrid exchange-correlation (XC-)functionals with a high percentage of Hartree-Fock like exchange (e.g. BHLYP) or range-separated XC-functionals to circumvent problems related to the description of charge-transfer excitations. Concentrating on the results obtained with TD-BHLYP we show that the optical gap in rocksalt nanoparticles displays a wide range of behavior; ranging from large optical gaps stemming from a localized excitation involving corner atoms in alkaline earth oxides to a delocalized excitation and small optical gaps in the transition metal chalcogenides. Finally, we rationalize this wide range of behaviour in terms of differences in the degree to which the Coulombic interaction between the excited electron and hole is screened in the different nanoparticles, and relate it to the optical dielectric constants of the bulk materials the nanoparticles are made from.
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Affiliation(s)
- Milena C C Wobbe
- Department of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ, UK.
| | - Martijn A Zwijnenburg
- Department of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ, UK.
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15
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Schneider J, Kollhoff F, Bernardi J, Kaftan A, Libuda J, Berger T, Laurin M, Diwald O. Porphyrin Metalation at the MgO Nanocube/Toluene Interface. ACS APPLIED MATERIALS & INTERFACES 2015; 7:22962-22969. [PMID: 26434978 DOI: 10.1021/acsami.5b08123] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Molecular insights into porphyrin adsorption on nanostructured metal oxide surfaces and associated ion exchange reactions are key to the development of functional hybrids for energy conversion, sensing, and light emission devices. Here we investigated the adsorption of tetraphenyl-porphyrin (2HTPP) from toluene solution on two types of MgO powder. We compare MgO nanocubes with an average size d < 10 nm and MgO cubes with 10 nm ≤ d ≤ 1000 nm. Using molecular spectroscopy techniques such as UV/vis transmission and diffuse reflectance (DR), photoluminescence (PL), and diffuse reflectance infrared Fourier-transform (DRIFT) spectroscopy in combination with structural characterization techniques (powder X-ray diffraction and transmission electron microscopy, TEM), we identified a new room temperature metalation reaction that converts 2HTPP into magnesium tetraphenyl-porphyrin (MgTPP). Mg(2+) uptake from the MgO nanocube surfaces and the concomitant protonation of the oxide surface level off at a concentration that corresponds to roughly one monolayer equivalent adsorbed on the MgO nanocubes. Larger MgO cubes, in contrast, show suppressed exchange, and only traces of MgTPP can be detected by photoluminescence.
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Affiliation(s)
- Johannes Schneider
- Department of Materials Science and Physics, Paris Lodron University of Salzburg , Hellbrunnerstrasse 34/III, A-5020 Salzburg, Austria
| | - Fabian Kollhoff
- Lehrstuhl für Physikalische Chemie II, Friedrich-Alexander-Universität Erlangen-Nürnberg , Egerlandstraße 3, 91058 Erlangen, Germany
| | - Johannes Bernardi
- University Service Center for Transmission Electron Microscopy, Vienna University of Technology , Wiedner Hauptstrasse 8-10, A-1040 Vienna, Austria
| | - Andre Kaftan
- Lehrstuhl für Physikalische Chemie II, Friedrich-Alexander-Universität Erlangen-Nürnberg , Egerlandstraße 3, 91058 Erlangen, Germany
| | - Jörg Libuda
- Lehrstuhl für Physikalische Chemie II, Friedrich-Alexander-Universität Erlangen-Nürnberg , Egerlandstraße 3, 91058 Erlangen, Germany
- Erlangen Catalysis Resource Center and Interdisciplinary Center for Interface-Controlled Processes, Friedrich-Alexander-Universität Erlangen-Nürnberg , 91058 Erlangen, Germany
| | - Thomas Berger
- Department of Materials Science and Physics, Paris Lodron University of Salzburg , Hellbrunnerstrasse 34/III, A-5020 Salzburg, Austria
| | - Mathias Laurin
- Lehrstuhl für Physikalische Chemie II, Friedrich-Alexander-Universität Erlangen-Nürnberg , Egerlandstraße 3, 91058 Erlangen, Germany
| | - Oliver Diwald
- Department of Materials Science and Physics, Paris Lodron University of Salzburg , Hellbrunnerstrasse 34/III, A-5020 Salzburg, Austria
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16
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Baumann SO, Schneider J, Sternig A, Thomele D, Stankic S, Berger T, Grönbeck H, Diwald O. Size effects in MgO cube dissolution. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:2770-6. [PMID: 25668706 DOI: 10.1021/la504651v] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Stability parameters and dissolution behavior of engineered nanomaterials in aqueous systems are critical to assess their functionality and fate under environmental conditions. Using scanning electron microscopy, transmission electron microscopy, and X-ray diffraction, we investigated the stability of cubic MgO particles in water. MgO dissolution proceeding via water dissociation at the oxide surface, disintegration of Mg(2+)-O(2-) surface elements, and their subsequent solvation ultimately leads to precipitation of Mg(OH)2 nanosheets. At a pH ≥ 10, MgO nanocubes with a size distribution below 10 nm quantitatively dissolve within few minutes and convert into Mg(OH)2 nanosheets. This effect is different from MgO cubes originating from magnesium combustion in air. With a size distribution in the range 10 nm ≤ d ≤ 1000 nm they dissolve with a significantly smaller dissolution rate in water. On these particles water induced etching generates (110) faces which, above a certain face area, dissolve at a rate equal to that of (100) planes.1 The delayed solubility of microcrystalline MgO is attributed to surface hydroxide induced self-inhibition effects occurring at the (100) and (110) microplanes. The present work underlines the importance of morphology evolution and surface faceting of engineered nanomaterials particles during their dissolution.
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Affiliation(s)
- Stefan O Baumann
- Institute of Particle Technology, Friedrich-Alexander Universität Erlangen-Nürnberg , Cauerstrasse 4, 91058 Erlangen, Germany
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17
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Gheisi A, Sternig A, Redhammer GJ, Diwald O. Thin water films and magnesium hydroxide fiber growth. RSC Adv 2015. [DOI: 10.1039/c5ra18202f] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
On oxide nanostructures thin water films act as reactant and provide a reaction medium for hydroxide fiber growth.
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Affiliation(s)
- Amir Gheisi
- Institute of Particle Technology
- Universität Erlangen-Nürnberg
- Germany
| | - Andreas Sternig
- Institute of Particle Technology
- Universität Erlangen-Nürnberg
- Germany
| | - Günther J. Redhammer
- Department of Materials Science and Physics
- Paris-Lodron University Salzburg
- Austria
| | - Oliver Diwald
- Department of Materials Science and Physics
- Paris-Lodron University Salzburg
- Austria
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18
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19
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Zhang X, Zheng Y, Feng X, Han X, Bai Z, Zhang Z. Calcination temperature-dependent surface structure and physicochemical properties of magnesium oxide. RSC Adv 2015. [DOI: 10.1039/c5ra17031a] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The electrochemical performance of MgO particles is highly dependent on their crystal structures resulting from calcination at different temperatures.
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Affiliation(s)
- Xiaoling Zhang
- School of Chemistry and Chemical Engineering
- Xi'an Shiyou University
- Xi'an 710065
- China
| | - Yajun Zheng
- School of Chemistry and Chemical Engineering
- Xi'an Shiyou University
- Xi'an 710065
- China
| | - Xiaoqin Feng
- School of Chemistry and Chemical Engineering
- Xi'an Shiyou University
- Xi'an 710065
- China
| | - Xiaoxiao Han
- School of Chemistry and Chemical Engineering
- Xi'an Shiyou University
- Xi'an 710065
- China
| | - Zongquan Bai
- School of Chemistry and Chemical Engineering
- Xi'an Shiyou University
- Xi'an 710065
- China
| | - Zhiping Zhang
- School of Chemistry and Chemical Engineering
- Xi'an Shiyou University
- Xi'an 710065
- China
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20
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Zhang L, Tang C, Gong H. Temperature effect on the binder-free nickel copper oxide nanowires with superior supercapacitor performance. NANOSCALE 2014; 6:12981-12989. [PMID: 25238283 DOI: 10.1039/c4nr04192e] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Although the use of nickel oxide in supercapacitor electrodes has been reported extensively, the effect of incorporating copper in the binary compound is not known. Arrays of nickel copper oxide nanowires on the current collector via a simple and industrially compatible route have been successfully synthesized. A systematic study on the effect of temperature is also presented. Strikingly, through conductivity modification and binder-free growth, the as-grown nanowires show high specific capacitance (2.24 F cm(2) at 10 mA; 1955 F g(-1) at 1 mV s(-1)), good rate capability (still 2.18 F cm(2) at 50 mA, 1542 F g(-1) at 50 mV s(-1)), and excellent cycle life (90% after 1000 cycles at a high charging-discharging rate 10 A g(-1)). An asymmetric full cell is then prepared and tested, and very high energy density (30 Wh kg(-1)) is achieved. Ideal capacitive behavior (rectangular shape of cyclic voltammetry) is shown with this tailored architecture of the full cell.
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Affiliation(s)
- Liuyang Zhang
- Department of Materials Science and Engineering, National University of Singapore, Singapore 117576.
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21
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Xie S, Bao S, Ouyang J, Zhou X, Kuang Q, Xie Z, Zheng L. Organic-Inorganic Interface-Induced Multi-Fluorescence of MgO Nanocrystal Clusters and Their Applications in Cellular Imaging. Chemistry 2014; 20:5244-52. [DOI: 10.1002/chem.201303927] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Indexed: 12/12/2022]
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22
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Wobbe MCC, Kerridge A, Zwijnenburg MA. Optical excitation of MgO nanoparticles; a computational perspective. Phys Chem Chem Phys 2014; 16:22052-61. [DOI: 10.1039/c4cp03442b] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The optical absorption spectra of magnesium oxide nanoparticles, along with the atomic centres responsible for the absorption, are studied using time-dependent density functional theory.
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Affiliation(s)
| | - Andrew Kerridge
- Department of Chemistry
- University College London
- London WC1H 0AJ, UK
- Department of Chemistry
- Lancaster University
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23
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McKenna KP. Electronic and chemical properties of a surface-terminated screw dislocation in MgO. J Am Chem Soc 2013; 135:18859-65. [PMID: 24279391 PMCID: PMC3892727 DOI: 10.1021/ja408342z] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Dislocations represent an important and ubiquitous class of topological defect found at the surfaces of metal oxide materials. They are thought to influence processes as diverse as crystal growth, corrosion, charge trapping, luminescence, molecular adsorption, and catalytic activity; however, their electronic and chemical properties remain poorly understood. Here, through a detailed first-principles investigation into the properties of a surface-terminated screw dislocation in MgO we provide atomistic insight into these issues. We show that surface dislocations can exhibit intriguing electron trapping properties which are important for understanding the chemical and electronic characteristics of oxide surfaces. The results presented in this article taken together with recent experimental reports show that surface dislocations can be equally as important as more commonly considered surface defects, such as steps, kinks, and vacancies, but are now just beginning to be understood.
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Affiliation(s)
- Keith P McKenna
- Department of Physics, University of York , Heslington, York YO10 5DD, United Kingdom
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24
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Sternig A, Diwald O. Surface Decoration of MgO Nanocubes with Sulfur Oxides: Experiment and Theory. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2013; 117:7727-7735. [PMID: 23616910 PMCID: PMC3632092 DOI: 10.1021/jp401432j] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/08/2013] [Revised: 03/15/2013] [Indexed: 06/02/2023]
Abstract
We investigated the effect of surface sulfate formation on the structure and spectroscopic properties of MgO nanocubes using X-ray diffraction, electron microscopy, several spectroscopic techniques, and ab initio calculations. After CS2 adsorption and oxidative treatment at elevated temperatures the MgO particles remain cubic and retain their average size of ∼6 nm. Their low coordinated surface elements (corners and edges) were found to bind sulfite and sulfate groups even after annealing up to 1173 K. The absence of MgO corner specific photoluminescence emission bands at 3.4 and 3.2 eV substantiates that sulfur modifies the electronic properties of characteristic surface structures, which we attribute to the formation of (SO3)2- and (SO4)2- groups at corners and edges. Ab initio calculations support these conclusions and provide insight into the local atomic structures and spectroscopic properties of these groups.
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25
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Vingurt D, Fuks D, Landau MV, Vidruk R, Herskowitz M. Grain boundaries at the surface of consolidated MgO nanocrystals and acid–base functionality. Phys Chem Chem Phys 2013; 15:14783-96. [DOI: 10.1039/c3cp51086g] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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26
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Sousa C, Tosoni S, Illas F. Theoretical Approaches to Excited-State-Related Phenomena in Oxide Surfaces. Chem Rev 2012. [DOI: 10.1021/cr300228z] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Carmen Sousa
- Departament de Química
Física and Institut de Química Teòrica i Computacional
(IQTCUB), Universitat de Barcelona, C/Martí
i Franquès 1, 08028 Barcelona, Spain
| | - Sergio Tosoni
- Departament de Química
Física and Institut de Química Teòrica i Computacional
(IQTCUB), Universitat de Barcelona, C/Martí
i Franquès 1, 08028 Barcelona, Spain
- Departamento de Química, Universidad de Las Palmas de Gran Canaria, Campus Universitario
de Tafira, 35017 Las Palmas de Gran Canaria, Spain
| | - Francesc Illas
- Departament de Química
Física and Institut de Química Teòrica i Computacional
(IQTCUB), Universitat de Barcelona, C/Martí
i Franquès 1, 08028 Barcelona, Spain
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