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Your search keyword '"Portehault, David"' showing total 14 results
Start Over Author "Portehault, David" Journal chemistry of materials
14 results on '"Portehault, David"'

4. Metal–Support Interactions in Pt-WO3Heterostructures: Role of WO3Polymorphism

Author

Gómez-Recio, Isabel, Thomas, Cyril, Méthivier, Christophe, Ruiz-González, María Luisa, González-Calbet, José M., and Portehault, David

Abstract

Ionic exchange under soft conditions yields nanoplatelets of tungsten bronzes with an original crystal structure doped with cobalt, copper, platinum, and cesium cations (h′-MxWO3). The optimal orientation of the tunnel-based crystal structure, perpendicular to the basal plane of the nanoplatelets, facilitates cation exchange so that the dopant cations are located inside the (WO6)6channels, as evidenced by scanning transmission electron microscopy and electron energy loss spectroscopy. This synthetic pathway allows one to obtain not only doped materials but also metallic nanoparticles supported over h′-WO3nanoplatelets after reduction. Consequently, this approach opens a route to target new hexagonal bronze compositions. We have used this approach to design Pt nanoparticles supported over the two known hexagonal WO3polymorphs: h′-WO3and h-WO3. By using the catalysis of CO oxidation as a probe, we highlight differences in the metal–support interaction on these Pt-WO3heterostructures, especially higher electron transfer from the newly discovered h′-WO3framework.

Published
2023
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6. Hydroxyapatites as Versatile Inorganic Hosts of Unusual Pentavalent Manganese Cations

Author

Varela, Aurea, primary, Gómez-Recio, Isabel, additional, Serrador, Laura, additional, Hernando, María, additional, Matesanz, Emilio, additional, Torres-Pardo, Almudena, additional, Fernández-Díaz, María Teresa, additional, Martínez, Jose L., additional, Gonell, Francisco, additional, Rousse, Gwenaelle, additional, Sanchez, Clément, additional, Laberty-Robert, Christel, additional, Portehault, David, additional, González-Calbet, José M., additional, and Parras, Marina, additional

Published
2020
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9. Unveiling the Potential of Redox Chemistry to Form Size-Tunable, High-Index Silicon Particles

Author

Parker, Megan A., Khaddad, Safa, Fares, Nicolas, Ghoridi, Anissa, Portehault, David, Bonhommeau, Sébastien, Amarouchene, Yacine, Rosa, Patrick, Gonidec, Mathieu, and Drisko, Glenna L.

Abstract

Silicon particles of intermediate sizes (75–200 nm) scatter visible wavelengths, making them promising candidates for optical devices. The solution synthesis of silicon particles in this size range, however, has proved challenging for chemists over the past few decades. Here, a solution-phase synthesis provides a pathway toward reaching size tunability between 45 and 230 nm via changing the reactant ratio in the reaction between a silicon Zintl phase (Na4Si4) with an amidinate-stabilized Si(IV) coordination complex. Coherent domain sizes, determined from powder X-ray diffraction, show that the crystallite sizes are uniform across all particle sizes, perhaps indicating an aggregation mechanism for particle growth. The amidinate ligands act to stabilize the particle surface. Combined surface techniques (ToF-SIMS, FTIR, and X-ray photoelectron spectroscopy) confirm the presence of amidinate ligands, as well as primary amine and a passive oxidation layer on the surface of the particles. The refractive index is measured for an individual particle using holographic optical microscopy, displaying a refractive index of nearly 4.1 at a wavelength of 532 nm. Thus, these particles should scatter light intensely at visible wavelengths, making them promising candidates for optical manipulation.

Published
2024
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