RadEMSL

EMSL’s radiochemistry facility, RadEMSL, is designed to accelerate scientific discovery and deepen the understanding of the chemical fate and transport of radionuclides in terrestrial and subsurface ecosystems.

The facility offers experimental and computational tools uniquely suited for actinide chemistry studies. The spectroscopic and imaging instruments at this facility are ideally designed for the study of contaminated environmental materials, examination of radionuclide speciation and detection of chemical signatures. RadEMSL houses nuclear magnetic resonance instruments and surface science capabilities, such as X-ray photoelectron spectroscopy, electron microscopy, electron microprobe, transmission electron microscopy and scanning electron microscopy. RadEMSL users also have access to expert computational, modeling and simulation resources and support.

The facility provides an environment where multiple experimental approaches are encouraged. Investigating problems at an integrated, cross-disciplinary level encourages holistic understanding, which ultimately provides policy makers the information they need to make sound remediation choices.

Like all of EMSL's capabilities, those housed in RadEMSL are available to the scientific community at typically no cost for openly published research. Scientists gain access to instruments and collaborate with onsite microscopy experts through a peer-reviewed proposal process. Research conducted in the annex requires special information and handling. Prior to submitting a proposal, potential users should familiarize themselves with the guidance for using and shipping radioactive material to the annex.

RadEMSL videos on EMSL's YouTube channel - Learn about the individual instruments in the facility and specifically how they advance subsurface and terrestrial ecosystem science.

And don't miss the virtual tour of RadEMSL.

Additional Information:

Instruments

Highlighted Research Applications EMSL's Bruker wide-bore 750 MHz solids/liquids spectrometer is dedicated to radiological and environmental...
Custodian(s): Nancy Washton
The Bruker EMX electron paramagnetic resonance (EPR) spectrometer performs continuous-wave magnetic resonance using electron spins to selectively...
Custodian(s): Eric Walter
Housed in EMSL's RadEMSL (Radiochemistry Annex), the field emission electron microprobe (EMP) enables chemical analysis and imaging of radionuclides...
Custodian(s): Bruce Arey
EMSL's Digital Instruments Radiological BioScope™ Atomic Force Microscope (AFM) allows radiological samples to be examined in fluids or air with...
Custodian(s): Kevin M. Rosso
The environmental scanning electron microscope (ESEM) is a new-generation SEM that can image samples under controlled environments and temperatures...
Custodian(s): Bruce Arey, Scott Lea

Science Highlights

Posted: September 22, 2015
The Science Uranium dioxide (UO2) contains the less soluble and immobile form of uranium in nature, so it is the desired end product of...
Posted: July 31, 2015
Corrosion in uranium dioxide, a major component of fuel rods in nuclear reactors, causes the rods to expand creating problems during routine...
Posted: April 14, 2015
The Science Scientists found the incorporation of neptunium (V) (NpO2+, neptunyl) and uranium (VI) (UO22+, uranyl) in a variety of mineral...
Posted: July 06, 2011
Scientists from Pacific Northwest National Laboratory and Rai Enviro-Chem, LLC, recently published first-ever results that illustrate the importance...

Instruments

There are no related projects at this time.

EMSL’s radiochemistry facility, RadEMSL, is designed to accelerate scientific discovery and deepen the understanding of the chemical fate and transport of radionuclides in terrestrial and subsurface ecosystems.

The facility offers experimental and computational tools uniquely suited for actinide chemistry studies. The spectroscopic and imaging instruments at this facility are ideally designed for the study of contaminated environmental materials, examination of radionuclide speciation and detection of chemical signatures. RadEMSL houses nuclear magnetic resonance instruments and surface science capabilities, such as X-ray photoelectron spectroscopy, electron microscopy, electron microprobe, transmission electron microscopy and scanning electron microscopy. RadEMSL users also have access to expert computational, modeling and simulation resources and support.

The facility provides an environment where multiple experimental approaches are encouraged. Investigating problems at an integrated, cross-disciplinary level encourages holistic understanding, which ultimately provides policy makers the information they need to make sound remediation choices.

Like all of EMSL's capabilities, those housed in RadEMSL are available to the scientific community at typically no cost for openly published research. Scientists gain access to instruments and collaborate with onsite microscopy experts through a peer-reviewed proposal process. Research conducted in the annex requires special information and handling. Prior to submitting a proposal, potential users should familiarize themselves with the guidance for using and shipping radioactive material to the annex.

RadEMSL videos on EMSL's YouTube channel - Learn about the individual instruments in the facility and specifically how they advance subsurface and terrestrial ecosystem science.

And don't miss the virtual tour of RadEMSL.

Additional Information:

Effect of Co/Ni ratios in cobalt nickel mixed oxide catalysts on methane combustion.

Abstract: 

A series of cobalt nickel mixed oxide catalysts with the varying ratios of Co to Ni, prepared by co-precipitation method, were applied to methane combustion. Among the various ratios, cobalt nickel mixed oxides having the ratios of Co to Ni of (50:50) and (67:33) demonstrate the highest activity for methane combustion. Structural analysis obtained from X-ray diffraction (XRD) and extended X-ray absorption fine structure (EXAFS) evidently demonstrates that CoNi (50:50) and (67:33) samples consist of NiCo2O4and NiO phase and, more importantly, NiCo2O4spinel structure is largely distorted, which is attributed to the insertion of Ni2+ions into octahedral sites in Co3O4spinel structure. Such structural dis-order results in the enhanced portion of surface oxygen species, thus leading to the improved reducibility of the catalysts in the low temperature region as evidenced by temperature programmed reduction by hydrogen (H2TPR) and X-ray photoelectron spectroscopy (XPS) O 1s results. They prove that structural disorder in cobalt nickel mixed oxides enhances the catalytic performance for methane combustion. Thus, it is concluded that a strong relationship between structural property and activity in cobalt nickel mixed oxide for methane combustion exists and, more importantly, distorted NiCo2O4spinel structure is found to be an active site for methane combustion.

Citation: 
Lim TH, SJ Cho, HS Yang, MH Engelhard, and DH Kim.2015."Effect of Co/Ni ratios in cobalt nickel mixed oxide catalysts on methane combustion."Applied Catalysis. A, General 505:62-69. doi:10.1016/j.apcata.2015.07.040
Authors: 
H Mark
Lim TH
SJ Cho
HS Yang
MH Engelhard
DH Kim
Volume: 
Issue: 
Pages: 
Publication year: 
2015

Effect of Graphene with Nanopores on Metal Clusters.

Abstract: 

Porous graphene, which is a novel type of defective graphene, shows excellent potential as a support material for metal clusters. In this work, the stability and electronic structures of metal clusters (Pd, Ir, Rh) supported on pristine graphene and graphene with different sizes of nanopore were investigated by first-principle density functional theory (DFT) calculations. Thereafter, CO adsorption and oxidation reaction on the Pd-graphene system were chosen to evaluate its catalytic performance. Graphene with nanopore can strongly stabilize the metal clusters and cause a substantial downshift of the d-band center of the metal clusters, thus decreasing CO adsorption. All binding energies, d-band centers, and adsorption energies show a linear change with the size of the nanopore: a bigger size of nanopore corresponds to a stronger metal clusters bond to the graphene, lower downshift of the d-band center, and weaker CO adsorption. By using a suitable size nanopore, supported Pd clusters on the graphene will have similar CO and O2 adsorption ability, thus leading to superior CO tolerance. The DFT calculated reaction energy barriers show that graphene with nanopore is a superior catalyst for CO oxidation reaction. These properties can play an important role in instructing graphene-supported metal catalyst preparation to prevent the diffusion or agglomeration of metal clusters and enhance catalytic performance. This work was supported by National Basic Research Program of China (973Program) (2013CB733501), the National Natural Science Foundation of China (NSFC-21176221, 21136001, 21101137, 21306169, and 91334013). D. Mei acknowledges the support from the US Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences & Biosciences. Pacific Northwest National Laboratory (PNNL) is a multiprogram national laboratory operated for DOE by Battelle. Computing time was granted by the grand challenge of computational catalysis of the William R. Wiley Environmental Molecular Sciences Laboratory (EMSL) and by the National Energy Research Scientific Computing Center (NERSC).

Citation: 
Zhou H, X Chen, L Wang, X Zhong, G Zhuang, X Li, D Mei, and J Wang.2015."Effect of Graphene with Nanopores on Metal Clusters."Physical Chemistry Chemical Physics. PCCP 17(37):24420-24426. doi:10.1039/c5cp04368a
Authors: 
H Zhou
X Chen
L Wang
X Zhong
G Zhuang
X Li
D Mei
J Wang
Capabilities: 
Volume: 
17
Issue: 
37
Pages: 
24420-24426
Publication year: 
2015

Dynamic Structural Changes of SiO2 Supported Pt−Ni Bimetallic Catalysts over Redox Treatments Revealed by NMR and EPR.

Abstract: 

SiO2 supported Pt−Ni bimetallic catalysts with different nickel loadings were prepared and their structural changes after redox treatments were studied by XRD, NMR, and EPR. It is found that the paramagnetic Ni species are mainly located on the surface of silica lattice. The relaxation of detected 29Si nuclei in our samples is mainly governed by a spin-diffusion mechanism. The paramagnetic effects are reflected in the spin−lattice relaxation of Q4 species, with the oxidized samples presenting faster relaxation rates than the corresponding reduced ones. Meanwhile the Q3 species, which are in close contact with the paramagnetic nickel ions, are “spectrally invisible”. In reducing atmosphere Ni gradually diffuses into Pt NPs to form PtNi alloys. While under oxidization treatment, the alloyed Ni atoms migrate outward from the core of Pt NPs and are oxidized. The main EPR spectrum results from reduced nickel species, and the reduced samples show stronger EPR signal than the corresponding oxidized ones. However, in the reduced samples, the superparamagnetic or ferromagnetic metallic Ni particles were inside the PtNi NPs, making their influence on the 29Si relaxation in the SiO2 support weaker than the oxidized samples.

Citation: 
Xu S, ED Walter, Z Zhao, MY Hu, X Han, JZ Hu, and X Bao.2015."Dynamic Structural Changes of SiO2 Supported Pt?Ni Bimetallic Catalysts over Redox Treatments Revealed by NMR and EPR."Journal of Physical Chemistry C 119(36):21219-21226. doi:10.1021/acs.jpcc.5b06344
Authors: 
Xu S
ED Walter
Z Zhao
MY Hu
X Han
JZ Hu
X Bao
Capabilities: 
Volume: 
119
Issue: 
36
Pages: 
21219-21226
Publication year: 
2015

Effects of Si/Al Ratio on Cu/SSZ-13 NH3-SCR Catalysts: Implications for the active Cu species and the Roles of Brønsted Acidity

Abstract: 

Cu/SSZ-13 catalysts with three Si/Al ratios of 6, 12 and 35 were synthesized with Cu incorporation via solution ion exchange. The implications of varying Si/Al ratios on the nature of the multiple Cu species that can be present in the SSZ-13 zeolite are a major focus of this work, as highlighted by the results of a variety of catalyst characterization and reaction kinetics measurements. Specifically, catalysts were characterized with surface area/pore volume measurements, temperature programmed reduction by H2 (H2-TPR), NH3 temperature programmed desorption (NH3-TPD), and DRIFTS and solid-state nuclear magnetic resonance (NMR) spectroscopies. Catalytic properties were examined using NO oxidation, ammonia oxidation, and standard ammonia selective catalytic reduction (NH3-SCR) reactions on selected catalysts under differential conditions. Besides indicating possible variably active multiple Cu species for these reactions, the measurements are also used to untangle some of the complexities caused by the interplay between redox of Cu ion centers and Brønsted acidity. All three reactions appear to follow a redox reaction mechanism, yet the roles of Brønsted acidity are quite different. For NO oxidation, increasing Si/Al ratio lowers Cu redox barriers, thus enhancing reaction rates. Brønsted acidity appears to play essentially no role for this reaction. For standard NH3-SCR, residual Brønsted acidity plays a significant beneficial role at both low- and high-temperature regimes. For NH3 oxidation, no clear trend is observed suggesting both Cu ion center redox and Brønsted acidity play important and perhaps competing roles. The authors gratefully acknowledge the US Department of Energy (DOE), Energy Efficiency and Renewable Energy, Vehicle Technologies Office for the support of this work. The research described in this paper was performed in the Environmental Molecular Sciences Laboratory (EMSL), a national scientific user facility sponsored by the DOE’s Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory (PNNL). PNNL is operated for the US DOE by Battelle.

Citation: 
Gao F, NM Washton, Y Wang, M Kollar, J Szanyi, and CHF Peden.2015."Effects of Si/Al Ratio on Cu/SSZ-13 NH3-SCR Catalysts: Implications for the active Cu species and the Roles of Brønsted Acidity ."Journal of Catalysis 331:25–38. doi:10.1016/j.jcat.2015.08.004
Authors: 
M Nancy
Janos Szanyi
Gao F
NM Washton
Y Wang
M Kollar
J Szanyi
CHF Peden
Volume: 
Issue: 
Pages: 
Publication year: 
2015

Infrared Multiphoton Dissociation Spectroscopy of a Gas-Phase Complex of Uranyl and 3Oxa-Glutaramide: An Extreme Red-Shift of

Abstract: 

The gas-phase complex UO2(TMOGA)22+ (TMOGA = tetramethyl-3-oxa-glutaramide) prepared by electrospray ionization was characterized by infrared multiphoton dissociation (IRMPD) spectroscopy. The IRMPD spectrum from 700–1800 cm–1 was interpreted using a computational study based on density functional theory. The predicted vibrational frequencies are in good agreement with the measured values, with an average deviation of only 8 cm–1 (<1%) and a maximum deviation of 21 cm–1 (<2%). The only IR peak assigned to the linear uranyl moiety was the asymmetric ν3 mode, which appeared at 965 cm–1 and was predicted by DFT as 953 cm–1. This ν3 frequency is red-shifted relative to bare uranyl, UO22+, by ca. 150 cm–1 due to electron donation from the TMOGA ligands. Based on the degree of red-shifting, it is inferred that two TMOGA oxygen-donor ligands have a greater effective gas basicity than the four monodentate acetone ligands in UO2(acetone)42+. The uranyl ν3 frequency was also computed for uranyl coordinated by two TMGA ligands, in which the central Oether of TMOGA has been replaced by CH2. The computed ν3 for UO2(TMGA)22+, 950 cm–1, is essentially the same as that for UO2(TMOGA)22+, suggesting that electron donation to uranyl from the Oether of TMOGA is minor. The computed ν3 asymmetric stretching frequencies for the three actinyl complexes, UO2(TMOGA)22+, NpO2(TMOGA)22+ and PuO2(TMOGA)22+, are comparable. This similarity is discussed in the context of the relationship between ν3 and intrinsic actinide-oxygen bond energies in actinyl complexes.

Citation: 
Gibson JK, H Hu, MJ Van Stipdonk, G Berden, J Oomens, and J Li.2015."Infrared Multiphoton Dissociation Spectroscopy of a Gas-Phase Complex of Uranyl and 3?Oxa-Glutaramide: An Extreme Red-Shift of the [O=U=O]2+ Asymmetric Stretch."Journal of Physical Chemistry A 119(14):3366–3374. doi:10.1021/jp512599e
Authors: 
JK Gibson
H Hu
MJ Van Stipdonk
G Berden
J Oomens
J Li
Facility: 
Volume: 
Issue: 
Pages: 
Publication year: 
2015

Isolation of the Copper Redox Steps in the Standard Selective CatalyticReduction on Cu-SSZ-13.

Abstract: 

Operando X-ray absorption experiments and density functional theory (DFT) calculations are reported that elucidate the role of copper redox chemistry in the selective catalytic reduction (SCR) of NO over Cu-exchanged SSZ-13. Catalysts prepared to contain only isolated, exchanged CuII ions evidence both CuII and CuI ions under standard SCR conditions at 473 K. Reactant cutoff experiments show that NO and NH3 together are necessary for CuII reduction to CuI. DFT calculations show that NO-assisted NH3 dissociation is both energetically favorable and accounts for the observed CuII reduction. The calculations predict in situ generation of
Brønsted sites proximal to CuI upon reduction, which we quantify in separate titration experiments. Both NO and O2 are necessary for oxidation of CuI to CuII, which DFT suggests to occur by a NO2 intermediate. Reaction of Cu-bound NO2 with
proximal NH4 + completes the catalytic cycle. N2 is produced in both reduction and oxidation half-cycles.

Citation: 
Paolucci C, AA Verma, SA Bates, VF Kispersky, JT Miller, R Gounder, N Delgass, F Ribeiro, and WF Schneider.2014."Isolation of the Copper Redox Steps in the Standard Selective CatalyticReduction on Cu-SSZ-13."Angewandte Chemie International Edition 53(44):11828–11833. doi:10.1002/anie.201407030
Authors: 
C Paolucci
AA Verma
SA Bates
VF Kispersky
JT Miller
R Gounder
N Delgass
F Ribeiro
WF Schneider
Volume: 
Issue: 
Pages: 
Publication year: 
2014

Ab Initio Modeling of Fe(II) Adsorption and Interfacial Electron Transfer at Goethite (α-FeOOH) Surfaces.

Abstract: 

Goethite (α-FeOOH) surfaces represent one of the most ubiquitous redox-active interfaces in the environment, playing an important role in biogeochemical metal cycling and contaminant residence in the subsurface. Fe(II)-catalyzed recrystallization of goethite is a fundamental process in this context, but the proposed Fe(II)aq-Fe(III)goethite electron and iron atom exchange mechanism of recrystallization remains poorly understood at the atomic level. We examine the adsorption of aqueous Fe(II) and subsequent interfacial electron transfer (ET) between adsorbed Fe(II) and structural Fe(III) at the (110) and (021) goethite surfaces using density functional theory calculations including Hubbard U corrections (DFT+U) aided by ab initio molecular dynamics simulations. We investigate various surface sites for the adsorption of Fe2+(H2O)6 in different coordination environments. Calculated energies for adsorbed complexes at both surfaces favor monodentate complexes with reduced 4- and 5-fold coordination over higher-dentate structures and 6- fold coordination. The hydrolysis of H2O ligands is observed for some pre-ET adsorbed Fe(II) configurations. ET from the adsorbed Fe(II) into the goethite lattice is calculated to be energetically uphill always, but simultaneous proton transfer from H2O ligands of the adsorbed complexes to the surface oxygen species stabilizes post-ET states. We find that surface defects such as oxygen vacancies near the adsorption site also can stabilize post-ET states, enabling the Fe(II)aq-Fe(III)goethite interfacial electron transfer reaction implied from experiments to proceed.

Citation: 
Alexandrov VY, and KM Rosso.2015."Ab Initio Modeling of Fe(II) Adsorption and Interfacial Electron Transfer at Goethite (?-FeOOH) Surfaces."Physical Chemistry Chemical Physics. PCCP 17(22):14518-14531. doi:10.1039/C5CP00921A
Authors: 
M Kevin
Alexrov VY
KM Rosso
Capabilities: 
Volume: 
17
Issue: 
22
Pages: 
14518-14531
Publication year: 
2015

Evidence for Carbonate Surface Complexation during Forsterite Carbonation in Wet Supercritical Carbon Dioxide.

Abstract: 

Continental flood basalts are attractive formations for geologic sequestration of carbon dioxide because of their reactive divalent-cation containing silicates, such as forsterite (Mg2SiO4), suitable for long-term trapping of CO2 mineralized as metal carbonates. The goal of this study was to investigate at a molecular level the carbonation products formed during the reaction of forsterite with supercritical CO2 (scCO2) as a function of the concentration of H2O adsorbed to the forsterite surface. Experiments were performed at 50 °C and 90 bar using an in situ IR titration capability, and post-reaction samples were examined by ex situ techniques, including SEM, XPS, FIB-TEM, TGA-MS, and MAS-NMR. Carbonation products and reaction extents varied greatly with adsorbed H2O. We show for the first time evidence of Mg-carbonate surface complexation under wet scCO2 conditions. Carbonate is found to be coordinated to Mg at the forsterite surface in a predominately bidentate fashion at adsorbed H2O concentrations below 27 µmol/m2. Above this concentration and up to 76 µmol/m2, monodentate coordinated complexes become dominant. Beyond a threshold adsorbed H2O concentration of 76 µmol/m2, crystalline carbonates continuously precipitate as magnesite, and the particles that form are hundreds of times larger than the estimated thicknesses of the adsorbed water films of about 7 to 15 Å. At an applied level, these results suggest that mineral carbonation in scCO2 dominated fluids near the wellbore and adjacent to caprocks will be insignificant and limited to surface complexation, unless adsorbed H2O concentrations are high enough to promote crystalline carbonate formation. At a fundamental level, the surface complexes and their dependence on adsorbed H2O concentration give insights regarding forsterite dissolution processes and magnesite nucleation and growth.

Citation: 
Loring JS, J Chen, P Benezeth Ep Gisquet, O Qafoku, ES Ilton, NM Washton, CJ Thompson, PF Martin, BP McGrail, KM Rosso, AR Felmy, and HT Schaef.2015."Evidence for Carbonate Surface Complexation during Forsterite Carbonation in Wet Supercritical Carbon Dioxide."Langmuir 31(27):7533-7543. doi:10.1021/acs.langmuir.5b01052
Authors: 
Qafoku Odeta
Nancy M Washton
Kevin M Rosso
Loring JS
J Chen
P Benezeth Ep Gisquet
O Qafoku
ES Ilton
NM Washton
CJ Thompson
PF Martin
BP McGrail
KM Rosso
AR Felmy
HT Schaef
Capabilities: 
Volume: 
31
Issue: 
27
Pages: 
7533-7543
Publication year: 
2015

Ab Initio Modeling of Bulk and Intragranular Diffusion in Ni Alloys.

Abstract: 

importance for understanding mechanisms of grain boundary (GB) oxidation causing environmental degradation and cracking of Ni-base structural alloys. In this study, first-principles calculations of vacancy-mediated diffusion are performed across a wide series of alloying elements commonly used in Ni-based superalloys, as well as interstitial diffusion of atomic oxygen and sulfur in the bulk, at the (111) surface, <110> symmetric tilt GBs of Ni corresponding to model low- (Σ=3/(111)) and high-energy (Σ=9/(221)) GBs. A substantial enhancement of diffusion is found for all species at the high-energy GB as compared to the bulk and the low-energy GB, with Cr, Mn and Ti exhibiting remarkably small activation barriers (<0.1 eV; ~10 times lower than in the bulk). Calculations also show that the bulk diffusion mechanism and kinetics differ for oxygen and sulfur, with oxygen having a faster mobility and preferentially diffusing through the tetrahedral interstitial sites in Ni matrix where it can be trapped in a local minimum.

Citation: 
Alexandrov VY, ML Sushko, DK Schreiber, SM Bruemmer, and KM Rosso.2015."Ab Initio Modeling of Bulk and Intragranular Diffusion in Ni Alloys."Journal of Physical Chemistry Letters 6(9):1618-1623. doi:10.1021/acs.jpclett.5b00177
Authors: 
M Kevin
Alexrov VY
ML Sushko
DK Schreiber
SM Bruemmer
KM Rosso
Capabilities: 
Volume: 
6
Issue: 
9
Pages: 
1618-1623
Publication year: 
2015

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