A5005795371- X-ray Diffraction in Crystallography
- Catalytic Processes in Materials Science
- Multiferroics and related materials
- Metal-Organic Frameworks: Synthesis and Applications
- Ferroelectric and Piezoelectric Materials
- Theoretical and Computational Physics
- Molten salt chemistry and electrochemical processes
- Radioactive element chemistry and processing
- Metallic Glasses and Amorphous Alloys
- Glass properties and applications
- Material Dynamics and Properties
- Catalysis and Oxidation Reactions
- Microwave Dielectric Ceramics Synthesis
- Solid-state spectroscopy and crystallography
- X-ray Spectroscopy and Fluorescence Analysis
- Electrocatalysts for Energy Conversion
- Magnetism in coordination complexes
- Nuclear materials and radiation effects
- Lanthanide and Transition Metal Complexes
- Advanced X-ray Imaging Techniques
- Advanced Condensed Matter Physics
- Geochemistry and Elemental Analysis
- Extraction and Separation Processes
- Dielectric properties of ceramics
- Iron oxide chemistry and applications
Argonne National Laboratory
2015-2024
Advanced Photon Source
2017-2019
Alex's Lemonade Stand Foundation
2019
Advanced Photonix (United States)
2017-2019
Abstract Layered transition metal oxides are appealing cathodes for sodium‐ion batteries due to their overall advantages in energy density and cost. But stabilities usually compromised by the complicated phase oxygen redox, particularly when operating at high voltages, leading poor structural stability substantial capacity loss. Here an integrated strategy combing high‐entropy design with superlattice‐stabilization extend cycle life enhance rate capability of layered is reported. It shown...
The redox chemistry and CO oxidation (2CO + O2 → 2CO2) activity of catalysts generated by the dispersion CuO on CeO2 nanorods were investigated using a multitechnique approach. Combined measurements time-resolved X-ray absorption near-edge spectroscopy (XANES) diffuse reflectance infrared Fourier transform (DRIFTS) in one setup made possible with development novel reaction cell which fluorescence mode detection was applied to collect XANES spectra. This is first reported example similar...
Schwertmannite effectively sorbs chromate (Cr(VI)), yet the sorption mechanisms remain elusive. We determined Cr(VI) on schwertmannite at pH 3.2 and 5 using combined macroscopic experiments with molecular-scale characterization by comparing them to arsenate (As(V)) sorption. adsorbs as bidentate-binuclear (BB) inner-sphere complexes through exchanging more sulfate less >Fe-OH/OH2, 0.59-0.71 released per sorbed. While As(V) also forms BB complexes, it exchanges >Fe-OH/OH2 equally 0.49-0.52 At...
Detailed analysis of electrochemical reactions occurring in rechargeable Fluoride-Ion Batteries (FIBs) is provided by means synchrotron X-ray diffraction (XRD) and Pair Distribution Function (PDF) analysis.
Abstract Weakly coupled relaxors based on compositions (1‐ x ) BaTiO 3 ‐ Bi Me O , where is a metal ion, have attracted attention as potential candidates for high‐temperature high‐energy density capacitors. However, the necessary content typically high with = 0.3‐0.4. In order to reduce problems associated compatibility base electrodes and due additional volatility, it desirable lower in overall composition these materials. Here, we explored possible way BiMeO through A‐site substitutions...
The formation of a spin glass usually requires both structural disorder and frustrated magnetic interactions. Consequently, the origin spin-glass behaviour in Y$_2$Mo$_2$O$_7$ $-$ which Mo$^{4+}$ ions occupy pyrochlore lattice with minimal compositional has been longstanding question. Here, we use neutron X-ray pair-distribution function (PDF) analysis to develop model that resolves apparent incompatibilities between previously-reported PDF, EXAFS NMR studies provides new physical mechanism...
Layered manganese (Mn) oxides, such as birnessite, can reductively transform into other phases and thereby affect the environmental behavior of Mn oxides. Solution chemistry strongly influences transformation, but effects oxyanions remain unknown. We determined products rates Mn(II)-driven reductive transformation δ-MnO2, a nanoparticulate hexagonal in presence phosphate or silicate at pH 6–8 wide range Mn(II)/MnO2 molar ratios. Without oxyanions, δ-MnO2 transforms triclinic birnessite...
A pronounced enthalpy release occurs around 1.38<italic>T</italic><sub>g</sub> in the prototypical metal–organic framework glass formed from ZIF-4 [Zn(C<sub>3</sub>H<sub>3</sub>N<sub>2</sub>)<sub>2</sub>], but there is no sign for any crystallization (<italic>i.e.</italic>, long-range ordering) taking place.
Temperature-induced polymorphic structural crossover in metallic liquid indium (In), tin (Sn), and antimony (Sb) is investigated by situ high-energy x-ray diffraction ab initio molecular dynamics simulations. The results demonstrate the existence of a temperature-induced reversible gradual these three liquids, reflecting from both ``static'' structures, e.g., peak positions structure factor pair distribution function, bond angle distribution, number tetrahedra, cluster connection, free...
We have studied the origin of exchange bias effect in ${\text{Au-Fe}}_{3}{\mathrm{O}}_{4}$ dumbbell nanoparticles two samples with different sizes Au seed (4.1 and 2.7 nm) same size ${\mathrm{Fe}}_{3}{\mathrm{O}}_{4}$ (9.8 nm). The magnetization, small-angle neutron-scattering, synchrotron x-ray diffraction, scanning transmission electron microscope measurements determined antiferromagnetic FeO w\"ustite phase within nanoparticles, originating at interface nanoparticles. between...
Saharan dust is an important phosphorus (P) supply to remote and oligotrophic parts of the oceans American lowland tropical rainforests. Phosphorus speciation in aeolian ultimately controls release bioavailability P after deposition, but its change during trans-Atlantic transport remains unclear. Using K-edge X-ray absorption near edge structure (XANES) spectroscopy, we showed that with increasing traveling distance from Sahara Desert Cape Verde Puerto Rico, about 570 4000 km, respectively,...
The structure of several nano-sized ceria, CeO2 , systems was investigated using neutron and X-ray diffraction absorption spectroscopy. Whilst both total pair distribution functions (PDFs) revealed that in all the samples occupancy Ce4+ O2- are very close to ideal stoichiometry, analysis Reverse Monte Carlo technique significant disorder around oxygen atoms ceria comparison highly crystalline NIST standard. In addition, main differences observed correlations from various techniques were...
Combining insights from diffuse reflection infrared Fourier transform spectroscopy and X-ray pair distribution function (PDF) analysis has the potential to deepen our understanding of complex materials systems including heterogeneous catalysts host–guest systems. This article describes development instrumentation non-ambient reaction cells that enable combined PDF–IR studies without compromise either measurement. Through careful selection IR spectrometer optics, instrument cell were adapted...
Using variable temperature atomic pair distribution function analysis, we study the emergence of charge density wave (CDW) order in $1T\text{\ensuremath{-}}{\mathrm{TiSe}}_{2}$ and find that it takes place via a two-step transition. First, upon decreasing to about 235(3) K, CDW-related lattice distortions emerge individual ${\mathrm{TiSe}}_{2}$ layers alone. Then, further temperature, two-dimensional couple widely recognized three-dimensional...
We present results from combined in situ infrared spectroscopy and total X-ray scattering studies on the evolution of catalytically active sites exemplary binary ternary Pt-based nanoalloys during a sequence CO oxidation–reactivation–CO oxidation reactions. find that when within particular compositional range, fresh may exhibit high catalytic activity for low-temperature oxidation. Using surface-specific atomic pair distribution functions (PDFs) extracted data, we that, regardless their...
The reaction between ceria and hydrogen has been subject to numerous theoretical experimental studies because of its importance as a catalytic material. Here, we present dynamic reversible evolution the cerium oxidation states observed through X-ray absorption spectroscopy experiments in addition investigation associated lattice expansion contraction diffraction PDF methods. Employing novel calculation temperature dependence Gibbs free energy consideration relationship instantaneous thermal...
Desorption of coordinated and non-coordinated guests from the nanoporous Prussian blue analogue MnII3[CoIII(CN)6]2(H2O)6∙x{H2O} was probed by simultaneous pair distribution function infrared spectroscopy measurements. The combined data shows how release different sites is coupled to structural relaxation framework.
Abstract
SO2 linkage photoisomerization in crystalline ruthenium-based complexes has demonstrated nanophotonic phenomena such as optical switching and nano-optomechanical transduction. Molecular insights into these materials have been explored largely via the characterization of their photoinduced crystal structures situ single-crystal X-ray diffraction, known photocrystallography. Photoinduced molecular disorder is present, which photocrystallography can model to extent that it confined within...
The peculiar characteristics of relaxors, viz., a frequency-dependent dielectric permittivity peak and good functional properties (dielectric, electromechanical, electrocaloric, etc.), are attributed to nanoscale regions with correlated dipoles, or polar nanoregions (PNRs). However, the exact nature PNRs their contribution relaxor behavior remains debatable. In recent years, solid solutions $\mathrm{BaTi}{\mathrm{O}}_{3}\text{\ensuremath{-}}\mathrm{Bi}\mathrm{Me}{\mathrm{O}}_{3}$ (where Me...