A5069926157- Spectroscopy and Quantum Chemical Studies
- Phase Equilibria and Thermodynamics
- Chemical and Physical Properties in Aqueous Solutions
- Analytical Chemistry and Chromatography
- Catalytic Processes in Materials Science
- Subcritical and Supercritical Water Processes
- Electrochemical Analysis and Applications
- Metal-Organic Frameworks: Synthesis and Applications
- Catalysis and Oxidation Reactions
- Surfactants and Colloidal Systems
- Zeolite Catalysis and Synthesis
- Catalysis and Hydrodesulfurization Studies
- X-ray Spectroscopy and Fluorescence Analysis
- X-ray Diffraction in Crystallography
- Iron oxide chemistry and applications
- Electrocatalysts for Energy Conversion
- Radioactive element chemistry and processing
- Advanced Chemical Physics Studies
- Petroleum Processing and Analysis
- Photochemistry and Electron Transfer Studies
- Asymmetric Hydrogenation and Catalysis
- Nanomaterials for catalytic reactions
- Thermodynamic properties of mixtures
- Electrostatics and Colloid Interactions
- Nanocluster Synthesis and Applications
Pacific Northwest National Laboratory
2015-2024
Battelle
1995-2023
Sandia National Laboratories
2023
Sandia National Laboratories California
2017-2019
Richland College
1990-2019
Argonne National Laboratory
2007-2018
Environmental Molecular Sciences Laboratory
2009-2018
University of Washington
2018
The University of Queensland
2018
Swiss Light Source
2018
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTRapid expansion of supercritical fluid solutions: solute formation powders, thin films, and fibersDean W. Matson, John L. Fulton, Robert C. Petersen, Richard D. SmithCite this: Ind. Eng. Chem. Res. 1987, 26, 11, 2298–2306Publication Date (Print):November 1, 1987Publication History Published online1 May 2002Published inissue 1 November 1987https://doi.org/10.1021/ie00071a021RIGHTS & PERMISSIONSArticle Views1307Altmetric-Citations288LEARN ABOUT THESE...
Copper oxide clusters synthesized via atomic layer deposition on the nodes of metal–organic framework (MOF) NU-1000 are active for oxidation methane to methanol under mild reaction conditions. Analysis chemical reactivity, in situ X-ray absorption spectroscopy, and density functional theory calculations used determine structure/activity relations Cu-NU-1000 catalytic system. The Cu-loaded MOF contained Cu-oxo a few Cu atoms. was present ambient conditions as mixture ∼15% Cu+ ∼85% Cu2+....
Developing supported single-site catalysts is an important goal in heterogeneous catalysis since the well-defined active sites afford opportunities for detailed mechanistic studies, thereby facilitating design of improved catalysts. We present herein a method installing Ni ions uniformly and precisely on node Zr-based metal–organic framework (MOF), NU-1000, high density large quantity (denoted as Ni-AIM) using atomic layer deposition (ALD) MOF (AIM). Ni-AIM demonstrated to be efficient...
The degree of substitution Si4+ by Al3+ in the oxygen-terminated tetrahedra (Al T-sites) zeolites determines concentration ion-exchange and Brønsted acid sites. Because location associated subtle variations bond angles influence strength, quantitative information about Al T-sites framework is critical to rationalize catalytic properties design new catalysts. A analysis reported that uses a combination extended X-ray absorption fine structure (EXAFS) 27Al MAS NMR spectroscopy supported...
Mononuclear and dinuclear copper species were synthesized at the nodes of an NU-1000 metal–organic framework (MOF) via cation exchange subsequent oxidation 200 °C in oxygen. Copper-exchanged MOFs are active for selectively converting methane to methanol 150–200 °C. At 150 1 bar methane, approximately a third centers involved methanol. Methanol productivity increased by 3–4-fold selectivity from 70% 90% increasing pressure 40 bar. Density functional theory showed that reaction pathways on...
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTSynthesizing and Dispersing Silver Nanoparticles in a Water-in-Supercritical Carbon Dioxide MicroemulsionMin Ji, Xiaoyuan Chen, Chien M. Wai, John L. FultonView Author Information Department of Chemistry, University Idaho Moscow, 83844 Environmental Health Sciences Division Pacific Northwest National Laboratory Richland, Washington 99352 Cite this: J. Am. Chem. Soc. 1999, 121, 11, 2631–2632Publication Date (Web):March 9, 1999Publication...
X-ray absorption fine structure (XAFS) spectroscopy was used to probe the effects of concentration on first-shell Ca2+ in aqueous solution. Measurements were carried out under ambient conditions using a bending magnet beamline (sector 20) at Advanced Photon Source, Argonne. The Ca K-edge EXAFS spectrum for 6 m CaCl2 yielded no evidence formation significant numbers Ca2+−Cl- contact ion pairs even such high concentration, result confirmed by comparison with data dilute (0.2 m) reference...
In situ X-ray absorption fine structure spectroscopy (XAFS) and 11B NMR were used to study the rhodium-catalyzed dimerization reaction of dimethylaminoborane, (CH3)2NHBH3 or DMAB. XAFS spectra show that active form rhodium catalyst is most likely composed a six-atom Rh core surrounded by tightly bound external ligands. results presence monomeric dimethylamine borane (CH3)2NBH2, providing evidence hydrogen formation from homogeneous species occurs an intramolecular pathway. This in contrast...
Determining the true, kinetically dominant catalytically active species, in classic benzene hydrogenation system pioneered by Maitlis and co-workers 34 years ago starting with [RhCp*Cl(2)](2) (Cp* = [η(5)-C(5)(CH(3))(5)]), has proven to be one of most challenging case studies quest distinguish single-metal-based "homogeneous" from polymetallic, "heterogeneous" catalysis. The reason, this study will show, is previous failure use proper combination of: (i) operando spectroscopy determine...
X-ray absorption fine structure (XAFS) is used to determine the of rhodium cluster present during catalyzed dehydrocoupling amine boranes under operando conditions. We show how a variety XAFS strategies can be in combination with other analytical methods differentiate homogeneous from heterogeneous systems. Analysis situ spectra using series (NH3BH3, R2NHBH3, and RNH2BH3 where R = methyl, isopropyl, tert-butyl, cyclohexyl) catalyst precursor compounds (including...
Mechanisms of CaCO3 nucleation from solutions that depend on multistage pathways and the existence species far more complex than simple ions or ion pairs have recently been proposed. Herein, we provide a tightly coupled theoretical experimental study precede initial stages nucleation. Starting molecular simulations, succeed in correctly predicting bulk thermodynamic quantities data, including equilibrium constants, titration curves, detailed x-ray absorption spectra taken supersaturated...
Molecular interactions with both oxides and metals are essential for heterogenous catalysis, leading to remarkable synergistic impacts on activity selectivity. Here, we show that the direct link between two phases (and not merely being together) is required selectively hydrogenate CO2 methanol catalysts containing Cu ZrO2. Materials consisting of isolated particles or atomically dispersed Cu-O-Zr sites only catalyze reverse water-gas shift reaction. In contrast, a metal organic framework...
A combination of theory, X-ray diffraction (XRD) and extended x-ray absorption fine structure (EXAFS) are used to probe the hydration aqueous Na+. The high spatial resolution XRD measurements corresponds Qmax = 24 Å-1 while first-reported Na K-edge EXAFS have a corresponding 2k 16 Å-1. Both provide an accurate measure shape position first peak in Na-O pair distribution function, gNaO(r). measured distances 2.384 ± 0.003 Å 2.37 0.024 excellent agreement. These show much shorter distance than...
Promoters are ubiquitous in industrial heterogeneous catalysts. The wider roles of promoters accelerating catalysis and/or controlling selectivity are, however, not well understood. A model system has been developed where a heterobimetallic active site comprising an metal (Rh) and promoter ion (Ga) is preassembled delivered onto metal-organic framework (MOF) support, NU-1000. Rh-Ga sites NU-1000 selectively catalyze the hydrogenation acyclic alkynes to E-alkenes. overall stereoselectivity...
The role of the specific physicochemical properties ZrO2 phases on Ni/ZrO2 has been explored with respect to reduction stearic acid. Conversion pure m-ZrO2 is 1.3 times more active than t-ZrO2 , whereas Ni/m-ZrO2 three Ni/t-ZrO2 . Although hydrodeoxygenation acid can be catalyzed solely by Ni, synergistic interaction between Ni and support causes variations in reaction rates. Adsorption carboxylic group an oxygen vacancy abstraction α-hydrogen atom elimination produce a ketene key enhance...
We report the arene hydrogenation of ethers, amides, and esters at room temperature low hydrogen pressure, starting from [(CAAC)Rh(COD)Cl] (CAAC = cyclic alkyl amino carbene). Kinetic, mechanistic, Rh K-edge XAFS studies showed formation nanoparticles [(CAAC)Rh(COD)Cl], in contrast to a previous functioning as homogeneous catalyst for hydrogenation. determined that site-selective catalyzed by this system is under steric control, shown detailed competition experiments with derivatives bearing...
Single atoms and few-atom clusters of platinum are uniformly installed on the zirconia nodes a metal-organic framework (MOF) NU-1000 via targeted vapor-phase synthesis. The catalytic Pt clusters, site-isolated by organic linkers, shown to exhibit high activity for ethylene hydrogenation while exhibiting resistance sintering up 200 °C. In situ IR spectroscopy reveals presence both single that depend upon synthesis conditions. Operando X-ray absorption pair distribution analyses reveal unique...
Metal–organic frameworks (MOFs), with their well-ordered pore networks and tunable surface chemistries, offer a versatile platform for preparing well-defined nanostructures wherein functionality such as catalysis can be incorporated. Notably, atomic layer deposition (ALD) in MOFs has recently emerged approach to functionalize MOF surfaces wide variety of catalytic metal-oxo species. Understanding the structure newly deposited species how they are tethered within is critical understanding...
To resolve the fleeting structures of lanthanide Ln3+ aqua ions in solution, we (i) performed first ab initio molecular dynamics (AIMD) simulations entire series explicit water solvent using pseudopotentials and basis sets recently optimized for lanthanides (ii) measured symmetry hydrating waters about (Nd3+, Dy3+, Er3+, Lu3+) time with extended X-ray absorption fine structure (EXAFS). EXAFS spectra were experimentally generated from AIMD trajectories to directly compare simulation, which...
Single-atom catalysts are often reported to have catalytic properties that surpass those of nanoparticles, while a direct comparison sites common and different for both is lacking. Here we show single atoms Pt-group metals embedded into the surface Fe3O4 greatly enhanced interaction strength with CO2 compared surface. The strong adsorption on Rh corresponding low activation energies lead 2 orders magnitude higher conversion rates nanoparticles. This high activity stems from partially oxidic...
Abstract A promising metal-organic complex, iron (Fe)-NTMPA 2 , consisting of Fe(III) chloride and nitrilotri-(methylphosphonic acid) (NTMPA), is designed for use in aqueous redox flow batteries. full-cell testing, where a concentrated Fe-NTMPA anolyte (0.67 M) paired with Fe-CN catholyte, demonstrates exceptional cycling stability over 1000 charge/discharge cycles, noteworthy performances, including 96% capacity utilization, minimal fade rate 0.0013% per cycle (1.3% 1,000 cycles), high...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAggregation of Amphiphilic Molecules in Supercritical Carbon Dioxide: A Small Angle X-ray Scattering StudyJohn L. Fulton, David M. Pfund, J. B. McClain, T. Romack, E. Maury, R. Combes, Samulski, DeSimone, and Malcolm CapelCite this: Langmuir 1995, 11, 4241–4249Publication Date (Print):November 1, 1995Publication History Published online1 May 2002Published inissue 1 November...
A method for generating extended X-ray absorption fine-structure (EXAFS) spectra directly from molecular dynamics trajectories is described. Conventional are run, and configurations the trajectory saved at periodic intervals. Clusters containing EXAFS atom center extracted used as input to multiple scattering code FEFF6, which produces an spectrum each cluster. The separate individual clusters then averaged together get a configurationally that can be compared with experiment. tested on...
This paper presents recent advances in the use of molecular simulations and extended X-ray absorption fine structure (EXAFS) spectroscopy, which enable us to understand solvated ions solution. We report discuss EXAFS spectra related properties governing solvation processes different water methanol. Molecular dynamics (MD) trajectories are coupled electron scattering generate MD-EXAFS spectra, found be very good agreement with corresponding experimental measurements. From these simulated...