Publications by authors named "Marie-Anne Dourges"

6 Publications

  • Page 1 of 1

Controlled Nanostructuration of Cobalt Oxyhydroxide Electrode Material for Hybrid Supercapacitors.

Materials (Basel) 2021 Apr 29;14(9). Epub 2021 Apr 29.

CNRS, University of Bordeaux, Bordeaux INP, ICMCB UMR CNRS #5026, F-33600 Pessac, France.

Nanostructuration is one of the most promising strategies to develop performant electrode materials for energy storage devices, such as hybrid supercapacitors. In this work, we studied the influence of precipitation medium and the use of a series of 1-alkyl-3-methylimidazolium bromide ionic liquids for the nanostructuration of β(III) cobalt oxyhydroxides. Then, the effect of the nanostructuration and the impact of the different ionic liquids used during synthesis were investigated in terms of energy storage performances. First, we demonstrated that forward precipitation, in a cobalt-rich medium, leads to smaller particles with higher specific surface areas (SSA) and an enhanced mesoporosity. Introduction of ionic liquids (ILs) in the precipitation medium further strongly increased the specific surface area and the mesoporosity to achieve well-nanostructured materials with a very high SSA of 265 m/g and porosity of 0.43 cm/g. Additionally, we showed that ILs used as surfactant and template also functionalize the nanomaterial surface, leading to a beneficial synergy between the highly ionic conductive IL and the cobalt oxyhydroxide, which lowers the resistance charge transfer and improves the specific capacity. The nature of the ionic liquid had an important influence on the final electrochemical properties and the best performances were reached with the ionic liquid containing the longest alkyl chain.
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http://dx.doi.org/10.3390/ma14092325DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8124577PMC
April 2021

pH-Mediated Colorimetric and Luminescent Sensing of Aqueous Nitrate Anions by a Platinum(II) [email protected] Silica Composite.

ACS Appl Mater Interfaces 2021 Apr 31;13(14):16197-16209. Epub 2021 Mar 31.

Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, United States.

Increased levels of nitrate (NO) in the environment can be detrimental to human health. Herein, we report a robust, cost-effective, and scalable, hybrid material-based colorimetric/luminescent sensor technology for rapid, selective, sensitive, and interference-free NO detection. These hybrid materials are based on a square-planar platinum(II) salt [Pt(tpy)Cl]PF (tpy = 2,2';6',2″-terpyridine) supported on mesoporous silica. The platinum salt undergoes a vivid change in color and luminescence upon exposure to aqueous NO anions at pH ≤ 0 caused by substitution of the PF anions by aqueous NO. This change in photophysics of the platinum salt is induced by a rearrangement of its crystal lattice that leads to an extended Pt···Pt···Pt interaction, along with a concomitant change in its electronic structure. Furthermore, incorporating the material into mesoporous silica enhances the surface area and increases the detection sensitivity. A NO detection limit of 0.05 mM (3.1 ppm) is achieved, which is sufficiently lower than the ambient water quality limit of 0.16 mM (10 ppm) set by the United States Environmental Protection Agency. The colorimetric/luminescence of the hybrid material is highly selective to aqueous NO anions in the presence of other interfering anions, suggesting that this material is a promising candidate for the rapid NO detection and quantification in practical samples without separation, concentration, or other pretreatment steps.
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http://dx.doi.org/10.1021/acsami.0c20821DOI Listing
April 2021

Metal-organic magnets with large coercivity and ordering temperatures up to 242°C.

Science 2020 10;370(6516):587-592

Université de Bordeaux, CNRS, Centre de Recherche Paul Pascal, UMR 5031, F-33600 Pessac, France.

Magnets derived from inorganic materials (e.g., oxides, rare-earth-based, and intermetallic compounds) are key components of modern technological applications. Despite considerable success in a broad range of applications, these inorganic magnets suffer several drawbacks, including energetically expensive fabrication, limited availability of certain constituent elements, high density, and poor scope for chemical tunability. A promising design strategy for next-generation magnets relies on the versatile coordination chemistry of abundant metal ions and inexpensive organic ligands. Following this approach, we report the general, simple, and efficient synthesis of lightweight, molecule-based magnets by postsynthetic reduction of preassembled coordination networks that incorporate chromium metal ions and pyrazine building blocks. The resulting metal-organic ferrimagnets feature critical temperatures up to 242°C and a 7500-oersted room-temperature coercivity.
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http://dx.doi.org/10.1126/science.abb3861DOI Listing
October 2020

Silylation of bacterial cellulose to design membranes with intrinsic anti-bacterial properties.

Carbohydr Polym 2019 Sep 13;220:71-78. Epub 2019 May 13.

University of Bordeaux, LCPO, UMR 5629, F-33600 Pessac, France. Electronic address:

In this work, we report a convenient method of grafting non-leachable bioactive amine functions onto the surface of bacterial cellulose (BC) nanofibrils, via a simple silylation treatment in water. Two different silylation protocols, involving different solvents and post-treatments were envisaged and compared, using 3-aminopropyl-trimethoxysilane (APS) and (2-aminoethyl)-3-aminopropyl-trimethoxysilane (AEAPS) as silylating agents. In aqueous and controlled conditions, water-leaching resistant amino functions could be successfully introduced into BC, via a simple freeze-drying process. The silylated material remained highly porous, hygroscopic and displayed sufficient thermal stability to support the sterilization treatments generally required in medical applications. The impact of the silylation treatment on the intrinsic anti-bacterial properties of BC was investigated against the growth of Escherichia coli and Staphylococcus aureus. The results obtained after the in vitro studies revealed a significant growth reduction of S. aureus within the material.
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http://dx.doi.org/10.1016/j.carbpol.2019.05.009DOI Listing
September 2019

Preparation of Polyester PolyMIPEs by Polycondensation of Low-Molecular Weight Polyol and Divinyl Ester Using Microwave Activation.

Macromol Rapid Commun 2018 Dec 22;39(24):e1800632. Epub 2018 Oct 22.

University of Bordeaux, Institut des Sciences Moléculaires, UMR-CNRS 5255, F-33405, Talence, France.

Several stable non-aqueous apolar-in-polar medium internal phase emulsions (MIPEs) containing divinyl adipate and pentaerythritol in the continuous phase are formulated by varying the nature of the hydrocarbon. Polycondensation is then conducted either under conventional heating or microwave irradiation after addition of a commercially available organocatalyst. Solvent elimination and drying lead to the corresponding polyester polyMIPEs. A tremendous morphological difference between materials is observed according to the heating method employed. The particular efficiency of microwave activation in the polycondensation of the continuous phase of a non-aqueous emulsion is discussed.
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http://dx.doi.org/10.1002/marc.201800632DOI Listing
December 2018

Finely Tuned SnO Nanoparticles for Efficient Detection of Reducing and Oxidizing Gases: The Influence of Alkali Metal Cation on Gas-Sensing Properties.

ACS Appl Mater Interfaces 2018 Mar 16;10(12):10173-10184. Epub 2018 Mar 16.

Institut des Sciences Moléculaires , Université de Bordeaux, UMR 5255 CNRS , Talence 33405 , France.

Tin dioxide (SnO) nanoparticles were straightforwardly synthesized using an easily scaled-up liquid route that involves the hydrothermal treatment, either under acidic or basic conditions, of a commercial tin dioxide particle suspension including potassium counterions. After further thermal post-treatment, the nanomaterials have been thoroughly characterized by Fourier transform infrared and Raman spectroscopy, powder X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, and nitrogen sorption porosimetry. Varying pH conditions and temperature of the thermal treatment provided cassiterite SnO nanoparticles with crystallite sizes ranging from 7.3 to 9.7 nm and Brunauer-Emmett-Teller surface areas ranging from 61 to 106 m·g, acidic conditions favoring potassium cation removal. Upon exposure to a reducing gas (H, CO, and volatile organic compounds such as ethanol and acetone) or oxidizing gas (NO), layers of these SnO nanoparticles led to highly sensitive, reversible, and reproducible responses. The sensing results were discussed in regard to the crystallite size, specific area, valence band energy, Debye length, and chemical composition. Results highlight the impact of the counterion residuals, which affect the gas-sensing performance to an extent much higher than that of size and surface area effects. Tin dioxide nanoparticles prepared under acidic conditions and calcined in air showed the best sensing performances because of lower amount of potassium cations and higher crystallinity, despite the lower surface area.
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http://dx.doi.org/10.1021/acsami.7b18140DOI Listing
March 2018