A5036649393- Catalytic Processes in Materials Science
- X-ray Diffraction in Crystallography
- Catalysis and Oxidation Reactions
- Zeolite Catalysis and Synthesis
- Chemical Synthesis and Characterization
- Crystallization and Solubility Studies
- Crystal Structures and Properties
- Catalysis and Hydrodesulfurization Studies
- Copper-based nanomaterials and applications
- Nuclear materials and radiation effects
- Nanomaterials for catalytic reactions
- Solid-state spectroscopy and crystallography
- Advanced NMR Techniques and Applications
- Electronic and Structural Properties of Oxides
- Electrocatalysts for Energy Conversion
- High-pressure geophysics and materials
- Advanced Photocatalysis Techniques
- Clay minerals and soil interactions
- Inorganic Fluorides and Related Compounds
- Catalysts for Methane Reforming
- X-ray Spectroscopy and Fluorescence Analysis
- Crystallography and molecular interactions
- Thermal and Kinetic Analysis
- Industrial Gas Emission Control
- Mesoporous Materials and Catalysis
Marshall University
2022-2024
Brookhaven National Laboratory
2011-2021
Brookhaven College
1999-2011
Stony Brook University
1997-2010
Instituto de Catálisis y Petroleoquímica
2004-2010
Center for Functional Nanomaterials
2007-2010
Universidad de Cádiz
2009-2010
University of Tennessee at Knoxville
2010
New Jersey Institute of Technology
2009
Pacific Northwest National Laboratory
2004-2009
An image-plate (IP) detector coupled with high-energy synchrotron radiation was used for atomic pair distribution function (PDF) analysis, high probed momentum transfer Q max ≤ 28.5 Å −1 , from crystalline materials. Materials different structural complexities were measured to test the validity of quantitative data analysis. Experimental results are presented Ni, α-AlF 3 and layered Aurivillius type oxides α-Bi 4 V 2 O 11 γ-Bi 1.7 Ti 0.3 10.85 . Overall, diffraction patterns show good...
Time-resolved X-ray diffraction, absorption fine structure, and first-principles density functional calculations were used to investigate the reaction of CuO Cu(2)O with H(2) in detail. The mechanism for reduction is complex, involving an induction period embedding H into bulk oxide. in-situ experiments show that, under a normal supply hydrogen, reduces directly metallic Cu without formation intermediate or suboxide (i.e., no Cu(4)O(3) Cu(2)O). easier than Cu(2)O. apparent activation energy...
New information about the active sites for water gas shift (WGS) reaction over Cu−CeO2 systems was obtained using in-situ, time-resolved X-ray diffraction (TR-XRD), absorption spectroscopy (TR-XAS, Cu K and Ce L3 edges), infrared (DRIFTS). nanoparticles prepared by a novel reversed microemulsion method (doped Ce1-xCuxO2 sample) an impregnation (impregnated CuOx/CeO2 were studied. The results from all of samples indicate that both metallic copper oxygen vacancies in ceria involved generation...
Textures of calcite crystals from a variety mineralized tissues belonging to organisms four phyla were examined with high-resolution synchrotron x-ray radiation. Significant differences in coherence length and angular spread observed between taxonomic groups. Crystals polycrystalline skeletal ensembles more perfect than those that function as single-crystal elements. Different anisotropic effects on crystal texture for sea urchin mollusk crystals, whereas none was found the foraminifer,...
Two series of nanostructured oxidized copper−cerium catalysts with varying copper loadings, and prepared, respectively, by impregnation ceria coprecipitation the two components within reverse microemulsions, have been characterized in detail at structural electronic levels X-ray diffraction (XRD), Raman spectroscopy, high-resolution electron microscopy (HREM), energy dispersive spectroscopy (XEDS), photoelectron (XPS) (including Ar+-sputtering), absorption fine structure (XAFS). These...
A novel inverse CeO(2)/CuO catalyst for preferential oxidation of CO in H(2)-rich stream (CO-PROX) has been developed on the basis a hypothesis extracted from previous work group (JACS 2007, 129, 12064). Possible separation two competing reactions involved process (of and H(2), respectively) is key to modulation overall CO-PROX activity based involvement different sites as most active ones each reactions. Achievement large size CuO particles adequate CeO(2)-CuO interfacial configurations...
The majority of harmful atmospheric CO and NOx emissions are from vehicle exhausts. Although there has been success addressing at temperatures above 250 °C with selective catalytic reduction technology, during cold start (when the temperature is below 150 °C), a major challenge. Herein, we show can completely eliminate both simultaneously under realistic exhaust flow, using highly loaded (2 wt %) atomically dispersed palladium in extra-framework positions small-pore chabazite material as...
Reduction of an oxide in hydrogen is a method frequently employed the preparation active catalysts and electronic devices. Synchrotron-based time-resolved X-ray diffraction (XRD), absorption fine structure (NEXAFS/EXAFS), photoemission, first-principles density-functional (DF) slab calculations were used to study reaction H(2) with nickel oxide. In experiments NiO(100) crystal NiO powders, reduction observed at atmospheric pressures elevated temperatures (250-350 degrees C), but only after...
A compact reaction cell is described for in-situ experiments requiring control of both the temperature sample and atmosphere over sample. The incorporates an optional furnace capable temperatures up to ∼1273 K. design ability mount directly on a standard goniometer head allows portability large number diffraction instruments at synchrotron sources.
The structural and electronic properties of Ce(1-x)Cu(x)O(2) nano systems prepared by a reverse microemulsion method were characterized with synchrotron-based X-ray diffraction, absorption spectroscopy, Raman density functional calculations. Cu atoms embedded in ceria had an oxidation state higher than those the cations Cu(2)O or CuO. lattice Ce(1)(-x)Cu(x)O(2) still adopted fluorite-type structure, but it was highly distorted multiple cation-oxygen distances respect to single bond distance...
The ability of organisms to exercise control over crystal growth is wonderfully exemplified by skeleton formation in echinoderms. A sea urchin spine a unique composite single calcite and glycoproteins intercalated inside the during its growth. Here we performed detailed morphological high-resolution synchrotron X-ray diffraction study textures synthetic biogenic crystals. We show that intracrystalline macromolecules from spines, when allowed interact with growing crystals vitro, selectively...
Temperature-programmed reduction (TPR), synchrotron-based time-resolved X-ray diffraction (TR-XRD), extended absorption fine-structure (EXAFS), and near-edge structure (XANES) were employed in this work to systematically study the reaction of CuO Cu2O with CO gas molecules. Both TPR isothermal results showed that was easier reduce than under same conditions. In situ measurements XRD XANES a direct transformation pathway for (CuO → Cu) when there large supply CO, while they sequential step...
In this article the structural and electronic properties of CeO2 Ce1-xZrxO2 nanoparticles are investigated using time-resolved X-ray diffraction, absorption near-edge spectroscopy (XANES), density functional calculations. (x ≤ 0.5) particles in sizes between 4 7 nm were synthesized a novel microemulsion method. The atoms these adopted cubic or pseudocubic crystal structure. lattice constant decreased with increasing Zr content, varying from 5.4019 Å to 5.3066 Ce0.5Zr0.5O2. Within structure,...
Synchrotron-based time-resolved X-ray diffraction was used to study in situ the crystalline phases present during preparation of bulk and silica-supported MoP, Ni2P, MoNiP by reduction oxidic precursors hydrogen. Independent type precursor or presence silica as a support, formation metal phosphides occurs at temperatures between 600 800 °C. Since common species all cases are phosphate-type groups (POx), it seems that their hydrogen is final determining step MoNiP. Silica-stabilized phosphide...
A table has been compiled of the spatial disposition amino acid residues in human deoxy hemoglobin tetramer. The also indicates regions possible contact between each subunit and contacts subunits.
Significant nanoscale disorder of Cu and Ca atomic substitution is observed in CaCu(3)Ti(4)O(12), based on our integrated study using quantitative electron diffraction extended x-ray absorption fine structure. Unambiguous identification this previously omitted made possible by the unique sensitivity these probes to valence-electron distribution short-range order. Furthermore, first-principles-based theoretical analysis indicates that Ca-site atoms possess partially filled degenerate e(g)...
The structural and electronic properties of Ce1−xNixO2−y nanosystems prepared by a reverse microemulsion method were characterized with synchrotron-based X-ray diffraction, absorption spectroscopy, Raman density functional calculations. systems adopt lattice fluorite-type structure an acute local order where Ni displays strongly distorted (oxygen) nearest-neighbor coordination the presence atoms as first cation distances, pointing to existence Ni−O−Ni entities embedded into ceria lattice. A...