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Quinson J, Mathiesen JK, Schröder J, Dworzak A, Bizzotto F, Zana A, Simonsen SB, Theil Kuhn L, Oezaslan M, Jensen KMØ, Arenz M. Teaching old precursors new tricks: Fast room temperature synthesis of surfactant-free colloidal platinum nanoparticles. J Colloid Interface Sci 2020; 577:319-328. [PMID: 32497917 DOI: 10.1016/j.jcis.2020.05.078] [Citation(s) in RCA: 12] [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] [Received: 03/20/2020] [Revised: 05/14/2020] [Accepted: 05/19/2020] [Indexed: 10/24/2022]
Abstract
A fast, simple, instrument-free room temperature synthesis of stable electroactive surfactant-free colloidal Pt nanoparticles in alkaline methanol and methanol-water mixtures is presented. Pair distribution function (PDF) analysis suggests that methoxy substitution of chloride ligands from H2PtCl6 occurs in methanol. X-ray absorption spectroscopy (XAS) studies and UV-vis measurements show that solutions of H2PtCl6 in methanol age and are reduced to Pt(II) species over time. These species are ideal precursors to significantly reduce the induction period typically observed in colloidal Pt nanoparticle syntheses as well as the temperature needed to form nanoparticles. The room temperature synthesis presented here allows designing simple in situ studies of the nanoparticle formation. In situ infra-red spectroscopy gives insight into the formation and stabilization mechanism of surfactant-free nanoparticles by CO surface groups. Finally, the surfactant-free nanoparticles ca. 2-3 nm in diameter obtained are shown to be readily active electrocatalysts e.g. for methanol oxidation. The synthesis approach presented bears several advantages to design new studies and new syntheses of surfactant-free colloidal nanomaterials.
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Affiliation(s)
- J Quinson
- University of Copenhagen, Chemistry Department, Universitetsparken 5, 2100 Copenhagen Ø, Denmark.
| | - J K Mathiesen
- University of Copenhagen, Chemistry Department, Universitetsparken 5, 2100 Copenhagen Ø, Denmark
| | - J Schröder
- University of Bern, Department of Chemistry and Biochemistry, Freiestrasse 3 CH-3012 Bern, Switzerland
| | - A Dworzak
- School of Mathematics and Science, Department of Chemistry, Carl von Ossietzky Universität Oldenburg, 26111 Oldenburg, Germany
| | - F Bizzotto
- University of Bern, Department of Chemistry and Biochemistry, Freiestrasse 3 CH-3012 Bern, Switzerland
| | - A Zana
- University of Bern, Department of Chemistry and Biochemistry, Freiestrasse 3 CH-3012 Bern, Switzerland
| | - S B Simonsen
- Technical, University of Denmark, Department of Energy Conversion and Storage, Fysikvej Bldg. 310, DK-2800 Kgs. Lyngby, Denmark
| | - L Theil Kuhn
- Technical, University of Denmark, Department of Energy Conversion and Storage, Fysikvej Bldg. 310, DK-2800 Kgs. Lyngby, Denmark
| | - M Oezaslan
- School of Mathematics and Science, Department of Chemistry, Carl von Ossietzky Universität Oldenburg, 26111 Oldenburg, Germany
| | - K M Ø Jensen
- University of Copenhagen, Chemistry Department, Universitetsparken 5, 2100 Copenhagen Ø, Denmark.
| | - M Arenz
- University of Bern, Department of Chemistry and Biochemistry, Freiestrasse 3 CH-3012 Bern, Switzerland.
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Solgaard AM, Simonsen SB, Grinsted A, Mottram R, Karlsson NB, Hansen K, Kusk A, Sørensen LS. Hagen Bræ: A Surging Glacier in North Greenland-35 Years of Observations. Geophys Res Lett 2020; 47:e2019GL085802. [PMID: 32713980 PMCID: PMC7375144 DOI: 10.1029/2019gl085802] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 02/21/2020] [Accepted: 02/21/2020] [Indexed: 06/11/2023]
Abstract
We use remotely sensed ice velocities in combination with observations of surface elevation and glacier area change to investigate the dynamics of Hagen Bræ, North Greenland in high detail over the last 35 years. From our data, we can establish for the first time that Hagen Bræ is a surge-type glacier with characteristics of both Alaskan- and Svalbard-type surging glaciers. We argue that the observed surge was preconditioned by the glacier geometry and triggered by englacially stored meltwater. At present, the glacier is in a transitional state between active and quiescence phases and is not building up to its pre-surge geometry. We suggest that the glacier is adjusting to the loss of its floating section, general thinning, and changes in fjord conditions that occurred over the study period which are unrelated to the surge behavior. The high temporal resolution of the ice velocity data gives insight to the sub-annual glacier flow.
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Affiliation(s)
- A. M. Solgaard
- The Department of Glaciology and ClimateThe Geological Survey of Denmark and Greenland (GEUS)CopenhagenDenmark
| | - S. B. Simonsen
- National Space InstituteTechnical University of DenmarkLyngbyDenmark
| | - A. Grinsted
- Physics of Ice, Climate, and EarthNiels Bohr Institute, University of CopenhagenCopenhagenDenmark
| | - R. Mottram
- Danish Meteorological Institute (DMI)CopenhagenDenmark
| | - N. B. Karlsson
- The Department of Glaciology and ClimateThe Geological Survey of Denmark and Greenland (GEUS)CopenhagenDenmark
| | - K. Hansen
- The Department of Glaciology and ClimateThe Geological Survey of Denmark and Greenland (GEUS)CopenhagenDenmark
| | - A. Kusk
- National Space InstituteTechnical University of DenmarkLyngbyDenmark
| | - L. S. Sørensen
- National Space InstituteTechnical University of DenmarkLyngbyDenmark
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Simonsen SB, Shao J, Zhang W. Structural evolution during calcination and sintering of a (La 0.6Sr 0.4) 0.99CoO 3-δ nanofiber prepared by electrospinning. Nanotechnology 2017; 28:265402. [PMID: 28513468 DOI: 10.1088/1361-6528/aa73a6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Design of three-dimensional metal oxide nanofibers by electrospinning is being widely explored. However, the impacts of calcination and sintering on the resulting morphology remain unknown. For the first time, (La0.6Sr0.4)0.99CoO3-δ (LSC) nanofiber, which is among the most promising electrode materials for solid oxide fuel cells, was synthesized by sol-gel electrospinning. By elevating the temperature in oxygen using in situ transmission electron microscopy, we discovered the structural transitions from nanofibers to nanotubes and then to nano-pearl strings. This facile and up-scalable method can be widely applied to design metal oxide one-dimensional nanomaterials with precise control in both geometry (nanofiber, nanotube and nano-pearl string) and surface area (by varying grain size).
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Affiliation(s)
- S B Simonsen
- Department of Energy Conversion and Storage, Technical University of Denmark, Frederiksborgvej 399, Roskilde, DK-4000, Denmark
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Mirbagheri N, Engberg S, Crovetto A, Simonsen SB, Hansen O, Lam YM, Schou J. Synthesis of ligand-free CZTS nanoparticles via a facile hot injection route. Nanotechnology 2016; 27:185603. [PMID: 27005863 DOI: 10.1088/0957-4484/27/18/185603] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Single-phase, ligand-free Cu2ZnSnS4 (CZTS) nanoparticles that can be dispersed in polar solvents are desirable for thin film solar cell fabrication, since water can be used as the solvent for the nanoparticle ink. In this work, ligand-free nanoparticles were synthesized using a simple hot injection method and the precursor concentration in the reaction medium was tuned to control the final product. The as-synthesized nanoparticles were characterized using various techniques, and were found to have a near-stoichiometric composition and a phase-pure kesterite crystal structure. No secondary phases were detected with Raman spectroscopy or scanning transmission electron microscopy energy dispersive x-ray spectroscopy. Furthermore, high resolution transmission electron microscopy showed large-sized nanoparticles with an average diameter of 23 nm ± 11 nm. This approach avoids all organic materials and toxic solvents that otherwise could hinder grain growth and limit the deposition techniques. In addition the synthesis route presented here results in nanoparticles of a large size compared to other ligand-free CZTS nanoparticles, due to the high boiling point of the solvents selected. Large particle size in CZTS nanoparticle solar cells may lead to a promising device performance. The results obtained demonstrate the suitability of the synthesized nanoparticles for application in low cost thin film solar cells.
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Affiliation(s)
- N Mirbagheri
- DTU Fotonik, Department of Photonics Engineering, Technical University of Denmark, DK-4000 Roskilde, Denmark
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