A5065335458- X-ray Spectroscopy and Fluorescence Analysis
- Radioactive element chemistry and processing
- Heavy metals in environment
- Electron and X-Ray Spectroscopy Techniques
- Trace Elements in Health
- Catalytic Processes in Materials Science
- Magnetic properties of thin films
- Geochemistry and Geologic Mapping
- Geochemistry and Elemental Analysis
- Nanoparticles: synthesis and applications
- Metal Extraction and Bioleaching
- Advancements in Battery Materials
- Arsenic contamination and mitigation
- Metal complexes synthesis and properties
- Electrocatalysts for Energy Conversion
- Geological and Geochemical Analysis
- Magnetic and transport properties of perovskites and related materials
- Advanced Chemical Physics Studies
- nanoparticles nucleation surface interactions
- Mine drainage and remediation techniques
- Extraction and Separation Processes
- Iron oxide chemistry and applications
- X-ray Diffraction in Crystallography
- Metal-Catalyzed Oxygenation Mechanisms
- Advanced Battery Materials and Technologies
European Synchrotron Radiation Facility
2011-2025
Université Grenoble Alpes
2016-2025
Institut Néel
2008-2025
Observatoire des Sciences de l'Univers de Grenoble
2015-2024
Centre National de la Recherche Scientifique
2015-2024
Observatoire des sciences de l'Univers Paris-Saclay
2015-2024
Institut de Recherche pour le Développement
2018-2023
Météo-France
2019-2023
Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement
2022-2023
Institut de physique du globe de Paris
2023
The chemical forms of zinc (Zn) in the Zn-tolerant and hyperaccumulator Arabidopsis halleri non-tolerant nonaccumulator lyrata subsp. petraea were determined at molecular level by combining analyses, extended x-ray absorption spectroscopy (EXAFS), synchrotron-based microfluorescence, muEXAFS. Plants grown hydroponics with various Zn concentrations, A. specimens growing naturally a contaminated site also collected. speciation was independent origin plants (contaminated or non-contaminated)...
Cerium dioxide nanoparticles have been proposed for an increasing number of applications in biomedicine, cosmetic, as polishing materials and also byproducts from automotive fuel additives. The aim this study was to examine the potential vitro cyto- genotoxicity nano-sized CeO2 (7 nm) on human dermal fibroblasts. By combining a physico-chemical (geno)toxicological approach, we defined causal mechanisms linking properties nano-CeO2 with their biological effects. Using X-ray absorption...
When normalized per unit of surface area, the quantity arsenic adsorbed at maghemite remains constant for particles between 300 and 20 nm. However, nanoparticles smaller than nm exhibit enhanced adsorption capacity. The origin this observed size-dependence or "nano effect" is unclear. Arsenic was chosen as a probe structure to explore mechanisms occurring (6 nm). Two factors contributing reactivity nanoscale maghemites were determined. first related size-dependent structural modification...
FAME is the French Absorption spectroscopy beamline in Material and Environmental sciences at ESRF (France), operational since September 2002. Technically speaking, source a 0.85 T bending magnet main optical element two-crystals monochromator using either Si(111) or Si(220) monocrystals so that available energy ranges from 4 to 40 keV. The first crystal liquid nitrogen cooled order avoid thermal bump thus preserve resolution. second dynamically bent during scan focus beam horizontal plane....
This paper presents a comparison between several methods dedicated to the interpretation of V K-edge X-ray absorption near-edge structure (XANES) features. XANES spectra V-bearing standard compounds were measured in an effort evaluate advantages and limits each method. The include natural minerals synthetic containing vanadium at various oxidation state (from +3 +5) different symmetry (octahedral, tetrahedral, square pyramidal). Correlations normalized pre-edge peak area its centroid...
Significance Gold resources on Earth result from an exceptional concentration phenomenon yielding metal contents in ore a thousand to million times higher than those common rocks. We show that this process is controlled by sulfur radical ions ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msubsup> <mml:mtext>S</mml:mtext> <mml:mn>3</mml:mn> <mml:mo>−</mml:mo> </mml:msubsup> </mml:mrow> </mml:math> ), which strongly bind Au aqueous solution at...
Superparamagnetic iron oxide nanoparticles (SPIONs) with a mixed phase composition (γ-Fe2O3)(1-x)(Fe3O4)x and sizes between 9 20 nm were synthesized via coprecipitation either left uncoated or subsequently surface-stabilized citrate malate anions. The sizes, morphology, surface chemistry, magnetic properties of the characterized using transmission electron microscopy (TEM), Fourier transform infrared spectroscopy, superconducting quantum interference device measurements, respectively....
The study of the speciation highly diluted elements by X‐ray absorption spectroscopy (XAS) is extremely challenging, especially in environmental biogeochemistry sciences. Here we present an innovative synchrotron technique: high‐energy resolution fluorescence detected XAS (HERFD‐XAS). With this approach, measurement signal mode using a crystal analyzer spectrometer with ∼1‐eV energy helps to overcome restrictions on sample concentrations that can be typically measured solid‐state detector....
A new set-up is reported of an indirect cryogenic cooling system for a double-crystal monochromator which runs on the BM30b/FAME beamline at ESRF (Grenoble, France). This device has been conceived to limit vibrations first diffracting crystal and maintain it constant temperature. These points are crucial maximizing stability. Moreover, relative angular position second can be dynamically adjusted by piezoelectric transducer coupled with feedback in order always maximum rocking curve during...
The molecular-level speciation of arsenic has been determined in a soil profile the Massif Central near Auzon, France that was impacted by As-based pesticides combining conventional techniques (XRD, selective chemical extractions) with X-ray absorption spectroscopy (XAS). concentration is very high at top (>7000 mg kg(-1)) and decreases rapidly downward to few hundreds milligrams per kilogram. A thin layer schultenite (PbHAsO4), lead arsenate commonly used as an insecticide until middle 20th...
Arsenic sorption onto maghemite potentially contributes to arsenic retention in magnetite-based removal processes because is the most common oxidation product of magnetite and may form a coating on surfaces. Such reaction could also favor immobilization at redox boundaries groundwaters. The nature adsorption complexes particles, near-neutral pH under anoxic conditions, was investigated using X-ray absorption fine structure (XAFS) spectroscopy As K-edge. near edge spectra indicate that...
In Bacillus subtilis, the transcription factor PerR is an iron dependant sensor of H(2)O(2). The sensing mechanism relies on a selective metal catalysed oxidation two histidine residues regulatory site. Here we present first crystal structure active protein in complex with Mn(2+) ion. addition, X-ray absorption spectroscopy experiments were performed to characterize corresponding form protein. Both studies reveal penta-coordinate arrangement site that involves three histidines and...
Abstract The photocatalytic properties of TiO 2 modified by chromium are usually found to depend strongly on the preparation method. To clarify this problem, two series chromium‐doped titania with a content up 1.56 wt % have been prepared under hydrothermal conditions: first (Cr:TiO ) is intended dope bulk , whereas second (Cr/TiO load surface Cr. catalytic compared in oxidation formic acid. Characterization data provides evidence that Cr/TiO catalysts located as amorphous CrOOH clusters. In...
Photocatalytic hydrogen generation from water or oxygenates is foreseen as a sustainable energy production route. In spite of recent performance achievements through Pt particle downsizing, knowledge the prototypical Pt/TiO2 photocatalyst operation mechanism, in particular electronic state and stability phase under reaction conditions, remains limited. We have investigated atomically dispersed catalysts by pre-/postreaction scanning transmission electron microscopy operando X-ray absorption...
Pyrite (FeS 2 ), arsenopyrite (FeAsS) and löllingite (FeAs ) are exceptional gold concentrators on Earth; yet the exact redox structural state of this "invisible" forces driving its intake release by these minerals remain highly controversial.Here we applied high resolution X-ray absorption spectroscopy to Au-bearing pyrite iron sulfarsenides from hydrothermal deposits their synthetic analogues.We show that Au preferentially enters octahedral Fe sites [Au(As,S) 6 ] enriched in As, forming...
Platinum nanoclusters highly dispersed on γ-alumina are widely used as heterogeneous catalysts. To understand the chemical interplay between Pt nanoparticles, support, and reductive atmosphere, we performed X-ray absorption near edge structure (XANES) in situ experiments recorded high energy resolution fluorescence detection (HERFD) mode. Spectra assigned by comparison with simulated XANES spectra models obtained molecular dynamics (DFT-MD). We propose platinum cluster morphologies quantify...