A5049414090- Molten salt chemistry and electrochemical processes
- Radioactive element chemistry and processing
- Nuclear Materials and Properties
- Nanoporous metals and alloys
- Nuclear reactor physics and engineering
- Nuclear materials and radiation effects
- Electrochemical Analysis and Applications
- Spectroscopy and Laser Applications
- Ionic liquids properties and applications
- Metallurgical Processes and Thermodynamics
- Extraction and Separation Processes
- Mass Spectrometry Techniques and Applications
- Copper-based nanomaterials and applications
- CO2 Reduction Techniques and Catalysts
- Advanced Chemical Physics Studies
- Bauxite Residue and Utilization
- Analytical chemistry methods development
- Inorganic Fluorides and Related Compounds
- Microwave Dielectric Ceramics Synthesis
- Advanced Battery Materials and Technologies
- Advanced oxidation water treatment
- Electrocatalysts for Energy Conversion
- Molecular Spectroscopy and Structure
- Photochemistry and Electron Transfer Studies
- Advanced Photocatalysis Techniques
Brookhaven National Laboratory
2014-2024
University of North Carolina at Greensboro
2007
Using a new technique, which combines pulse radiolysis with nanosecond time-resolved infrared (TRIR) spectroscopy in the condensed phase, we have conducted detailed kinetic and mechanistic investigation of formation Mn-based CO2 reduction electrocatalyst, [Mn((t)Bu2-bpy)(CO)3]2 ((t)Bu2-bpy = 4,4'-(t)Bu2-2,2'-bipyridine), acetonitrile. The use TRIR allowed, for first time, direct observation all intermediates involved this process. Addition excess [(n)Bu4N][HCO2] to an acetonitrile solution...
Three-dimensional bicontinuous porous materials formed by dealloying contribute significantly to various applications including catalysis, sensor development and energy storage. This work studies a method of molten salt via real-time in situ synchrotron three-dimensional X-ray nano-tomography. Quantification morphological parameters determined that long-range diffusion is the rate-determining step for process. The subsequent coarsening rate was primarily surface controlled, with Rayleigh...
The development of technologies for nuclear reactors based on molten salts has seen a big resurgence. success thermodynamic models these hinges in part our ability to predict at the atomistic level behavior pure and their mixtures under range conditions. In this letter, we present high-energy X-ray scattering experiments molecular dynamics simulations that describe structure MgCl2 KCl. As one would expect, KCl is prototypical salt which governed by simple charge alternation. contrast, its...
Solution-processable organic semiconductors have potentials as visible photoelectrochemical (PEC) water splitting photoelectrodes due to their tunable small band gap and electronic energy levels, but they are typically limited by poor stability photocatalytic activity. Here, we demonstrate the direct PEC oxidation on solution-processed semiconductor thin films with improved performance ultrathin metal oxide passivation layers. N-type fullerene-derivative passivated sub-2 nm ZnO via atomic...
Understanding the factors that control solubility and speciation of metal ions in molten salts is key for their successful use salt reactors electrorefining. Here, we employ X-ray optical absorption spectroscopies molecular dynamics simulations to investigate coordination environment Ni(II) ZnCl2, where it poorly soluble, contrast with highly soluble Co(II) over a wide temperature range. In solid NiCl2, Ni ion octahedrally coordinated, whereas ZnCl2 host matrix favors tetrahedral...
Molten salts are of great interest as alternative solvents, electrolytes, and heat transfer fluids in many emerging technologies.
When coupled with transient absorption spectroscopy, pulse radiolysis, which utilizes high-energy electron pulses from an accelerator, is a powerful tool for investigating the kinetics and thermodynamics of wide range radiation-induced redox transfer processes. The majority these investigations detect species in UV, visible, or near-IR spectral regions. Unfortunately, often-broad featureless bands regions can make definitive identification intermediates difficult. Time-resolved vibrational...
In situ mid-infrared spectroscopy is a powerful technique for understanding the mechanism of CO2 reduction (CO2R) catalysts because it enables direct detection catalytic intermediates and products. Moreover, spectroelectrochemistry (SEC), coupling with electrochemistry, allows spectroscopic changes to be correlated applied potentials reveal potential-dependent that are often relevant photoelectrochemical reactions. Hybrid photoelectrodes, composed narrow bandgap semiconductor, like silicon...
Abstract Porous materials with high specific surface area, porosity, and electrical conductivity are promising for functional applications, including catalysis, sensing, energy storage. Molten salt dealloying was recently demonstrated in microwires as an alternative method to fabricate porous structures. The takes advantage of the selective dissolution process introduced by impurities often observed molten corrosion. This work further investigates bulk Ni–20Cr alloy both KCl–MgCl 2 KCl–NaCl...
Molten chloride salts are currently under consideration as combined coolant and liquid fuel for next-generation molten salt nuclear reactors. Unlike complementary light-water reactor technologies, the radiation science underpinning is in its infancy, thus requires a fundamental mechanistic investigation to elucidate radiation-driven chemistry within Here we present an electron pulse radiolysis kinetics study into behaviour of primary radiolytic species generated systems, i.e., solvated (eS-)...
First-of-a-kind temperature-controlled electron pulse radiolysis experiments facilitated the radiation-induced formation of Am(IV) in concentrated (6.0 M) HNO
To facilitate the development of molten salt reactor technologies, a fundamental understanding physical and chemical properties salts under combined conditions high temperature intense radiation fields is necessary. Optical spectroscopic (UV-Vis-near IR) electrochemical techniques are powerful analytical tools to probe molecular structure, speciation, thermodynamics, kinetics solution dynamics. Here, we report design fabrication three custom-made apparatus: (i) multi-port...
A versatile, compact heater designed at National Synchrotron Light Source-II for in situ X-ray nano-imaging a full-field transmission microscope is presented. Heater design challenging, combining tight spatial constraints with stringent requirements the temperature range and stability. Finite-element modeling analytical calculations were used to determine parameters. Performance tests demonstrated reliable stable performance, including maintaining exterior casing close room while operating...
Despite the significant impact of radiation-induced redox reactions on accessibility and lifetimes actinide oxidation states, fundamental knowledge aqueous metal ion radiation chemistry is limited, especially for late actinides. A quantitative understanding these intrinsic processes essential investigating properties We present here a picosecond electron pulse reaction kinetics study into trivalent berkelium (Bk(III)) californium (Cf(III)) ions in acidic solutions at ambient temperature. New...
A new transient interhalogen species (ICl •− ) has been identified in electron pulse irradiated molten chloride salt mixtures. This significant implications for the transport of fission-product iodine reactor environments.
Molten salts are proposed as liquid fuels or coolants in a new fleet of molten salt nuclear reactors that would have operational and safety advantages over present reactor systems. Under those conditions, the will be exposed to high radiation levels, understanding chemical effects radiolysis on fuel coolant is essential reliable, efficient sustainable operation. Building this begins with identifying primary products (solvated electrons (e solv – ) Cl 2 •– characterizing their reactivities,...
This study investigated the effects of adding 1 wt% CrCl2 and VCl2 on Cr corrosion in eutectic MgCl2-KCl at 773 K under an argon atmosphere, using electrochemistry immersion experiments. The redox potential V3+/V2+ was more negative than Cr2+/Cr, suggesting that V2+ can protect from dissolution. Additionally, morphological chemical evolutions with scanning transmission electron microscopy (STEM), energy-dispersive X-ray spectroscopy (EDS), energy loss (EELS) confirmed protection mechanism...
A multielectrode-based electrochemical cell allows the structural characterization of an amorphous thin-film water oxidation catalyst under various potentials using high-energy X-ray scattering and atomic pair distribution function (PDF) techniques. multielectrode with five electrodes provides a sufficiently low background signal to enable (HEXS) measurements amplifies extremely HEXS signals from samples for high-resolution PDF analysis in situ data catalysts. Glassy carbon (GC) creates...
In this article, a new technique we call Beam Action Spectroscopy via Inelastic Scattering (BASIS) is demonstrated. BASIS takes advantage of the sensitivity rotational state distributions in supersonic molecular beam to inelastic scattering within beam. We exploit achieve increased two very different types experiments. first, UV photodissociation spectrum OClO recovered by monitoring intensity changes pure transition spectator molecule (OCS) downstream from nozzle, revealing vibrational...
We describe the first implementation of broadband, nanosecond time-resolved step-scan Fourier transform infrared (S2-FT-IR) spectroscopy at a pulse radiolysis facility. This new technique allows rapid acquisition nano- to microsecond (TRIR) spectra transient species generated by liquid samples pulsed electron accelerator. Wide regions mid-infrared can be probed in single experiment, which often takes < 20-30 min complete. It is therefore powerful method for rapidly locating IR absorptions...