Radiochemistry Annex

EMSL’s Radiochemistry Annex is designed to accelerate scientific discovery and deepen the understanding of the chemical fate and transport of radionuclides in terrestrial and subsurface ecosystems.

The annex 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. The annex 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. Annex users also have access to expert computational, modeling and simulation resources and support.

The annex is 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 the annex 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.

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

And don't miss the virtual tour of our Radiochemistry Annex.

Instruments

Research applications Samples containing paramagnetics Soils (SOM and NOM) Metal oxide materials for catalysis applications Researchers may operate...
Custodian(s): Nancy Washton, Sarah D Burton
EMSL's Bruker wide-bore 750 MHz solids/liquids/imaging spectrometer is dedicated to radiological and environmental samples. Housed in the EMSL...
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
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
Housed in EMSL's Radiochemistry Annex, the field emission electron microprobe (EMP) enables chemical analysis and imaging of radionuclides with high...
Custodian(s): Bruce Arey

Science Highlights

Posted: July 06, 2011
Scientists from Pacific Northwest National Laboratory and Rai Enviro-Chem, LLC, recently published first-ever results that illustrate the importance...

EMSL’s Radiochemistry Annex is designed to accelerate scientific discovery and deepen the understanding of the chemical fate and transport of radionuclides in terrestrial and subsurface ecosystems.

The annex 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. The annex 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. Annex users also have access to expert computational, modeling and simulation resources and support.

The annex is 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 the annex 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.

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

And don't miss the virtual tour of our Radiochemistry Annex.

Enhanced Quantum Efficiency From Hybrid Cesium Halide/Copper Photocathode.

Abstract: 

The quantum efficiency of Cu is found to increase dramatically when coated by a CsI film and then irradiated by a UV laser. Over three orders of magnitude quantum efficiency enhancement at 266 nm is observed in CsI/Cu(100), indicating potential application in future photocathode devices. Upon laser irradiation, a large work function reduction to a value less than 2 eV is also observed, significantly greater than for similarly treated CsBr/Cu(100). The initial QE enhancement, prior to laser irradiation, is attributed to interface interaction, surface cleanliness and the intrinsic properties of the Cs halide film. Further QE enhancement following activation is attributed to formation of inter-band states and Cs metal accumulation at the interface induced by laser irradiation.

Citation: 
Kong L, AG Joly, TC Droubay, Y Gong, and WP Hess.2014."Enhanced Quantum Efficiency From Hybrid Cesium Halide/Copper Photocathode."Applied Physics Letters 104(17):Article No. 171106. doi:10.1063/1.4874339
Authors: 
L Kong
AG Joly
TC Droubay
Y Gong
WP Hess
Instruments: 
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0
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0
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0
Publication year: 
2014

Molecular Structure and Stability of Dissolved Lithium Polysulfide Species.

Abstract: 

Ability to predict the solubility and stability of lithium polysulfide is vital in realizing longer lasting lithium-sulfur batteries. Herein we report a combined computational and experimental spectroscopic analysis to understand the dissolution mechanism of lithium polysulfide species in an aprotic solvent medium. Multinuclear NMR and sulfur K-edge X-ray absorption (XAS) analysis reveals that the lithium exchange between polysulfide species and solvent molecule constitutes the first step in the dissolution process. Lithium exchange leads to de-lithiated polysulfide ions which subsequently forms highly reactive free radicals through disproportion reaction. The energy required for the disproportion and possible dimer formation reactions of the polysulfide species are analyzed using density functional theory (DFT) calculations. We validate our calculations with variable temperature electron spin resonance (ESR) measurements. Based on these findings, we discuss approaches to optimize the electrolyte in order to control the polysulfide solubility. The energy required for the disproportion and possible dimer formation reactions of the polysulfide species are analyzed using density functional theory (DFT) calculations. We validate our calculations with variable temperature electron spin resonance (ESR) measurements. Based on these findings, we discuss approaches to optimize the electrolyte in order to control the polysulfide solubility.

Citation: 
Vijayakumar M, N Govind, ED Walter, SD Burton, AK Shukla, A Devaraj, J Xiao, J Liu, CM Wang, AM Karim, and S Thevuthasan.2014."Molecular Structure and Stability of Dissolved Lithium Polysulfide Species."Physical Chemistry Chemical Physics. PCCP 16(22):10923-10932. doi:10.1039/c4cp00889H
Authors: 
M Vijayakumar
N Govind
ED Walter
SD Burton
AK Shukla
A Devaraj
J Xiao
J Liu
CM Wang
AM Karim
S Thevuthasan
Instruments: 
Volume: 
16
Issue: 
22
Pages: 
10923-10932
Publication year: 
2014

Methanol Synthesis from CO2 Hydrogenation over a Pd4/In2O3 Model Catalyst: A Combined DFT and Kinetic Study.

Abstract: 

Methanol synthesis from CO2 hydrogenation on Pd4/In2O3 has been investigated using density functional theory (DFT) and microkinetic modeling. In this study, three possible routes in the reaction network of CO2 + H2 → CH3OH + H2O have been examined. Our DFT results show that the HCOO route competes with the RWGS route whereas a high activation barrier kinetically blocks the HCOOH route. DFT results also suggest that H2COO* + H* ↔ H2CO* +OH* and cis-COOH* + H* ↔CO* + H2O* are the rate limiting steps in the HCOO route and the RWGS route, respectively. Microkinetic modeling results demonstrate that the HCOO route is the dominant reaction route for methanol synthesis from CO2 hydrogenation. We found that the activation of H adatom on the small Pd cluster and the presence of H2O on the In2O3 substrate play important roles in promoting the methanol synthesis. The hydroxyl adsorbed at the interface of Pd4/In2O3 induces the transformation of the supported Pd4 cluster from a butterfly structure into a tetrahedron structure. This important structure change not only indicates the dynamical nature of the supported nanoparticle catalyst structure during the reaction but also shifts the final hydrogenation step from H2COH to CH3O.

Citation: 
Ye J, C Liu, D Mei, and Q Ge.2014."Methanol Synthesis from CO2 Hydrogenation over a Pd4/In2O3 Model Catalyst: A Combined DFT and Kinetic Study."Journal of Catalysis 317:44-53. doi:10.1016/j.jcat.2014.06.002
Authors: 
Ye J
C Liu
D Mei
Q Ge
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0
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0
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2014

Mineralization of Basalts in the CO2-H2O-SO2-O2 System.

Abstract: 

Sequestering carbon dioxide (CO2) containing minor amounts of co-contaminants in geologic formations was investigated in the laboratory through the use of high pressure static experiments. Five different basalt samples were immersed in water equilibrated with supercritical CO2 containing 1wt% sulfur dioxide (SO2) and 1wt% oxygen (O2) at reservoir conditions (~100 bar, 90°C) for 49 and 98 days. Gypsum (CaSO4) was a common precipitate, occurred early as elongated blades with striations, and served as substrates for other mineral products. Bimodal pulses of water released during dehydroxylation were key indicators along with X-ray diffraction for verifying the presences of jarosite-alunite group minerals. Well-developed pseudocubic jarosite crystals formed surface coatings, and in some instances mixtures of natrojarosite and natroalunite aggregated into spherically shaped structures measuring 100 μm in diameter. Reaction products were also characterized using infrared spectroscopy, which indicated OH and Fe-O stretching modes. The presences of jarosite-alunite group minerals were found in the lower wavenumber region from 700–400 cm-1. A strong preferential incorporation of Fe(III) into natrojarosite was attributed to the oxidation potential of O2. Evidence of CO2 was detected during thermal decomposition of precipitates, suggesting the onset of mineral carbonation.

Citation: 
Schaef HT, JA Horner, AT Owen, CJ Thompson, JS Loring, and BP McGrail.2014."Mineralization of Basalts in the CO2-H2O-SO2-O2 System."Environmental Science & Technology 48(9):5298-5305. doi:10.1021/es404964j
Authors: 
HT Schaef
JA Horner
AT Owen
CJ Thompson
JS Loring
BP McGrail
Volume: 
48
Issue: 
9
Pages: 
5298-5305
Publication year: 
2014

A Facile Approach Using MgCl2 to Formulate High Performance Mg2+ Electrolytes for Rechargeable Mg Batteries.

Abstract: 

Rechargeable Mg batteries have been regarded as a viable battery technology for grid scale energy storage and transportation applications. However, the limited performance of Mg2+ electrolytes has been a primary technical hurdle to develop high energy density rechargeable Mg batteries. In this study, MgCl2 is demonstrated as a non-nucleophilic and cheap Mg2+ source in combining with Al Lewis acids (AlCl3, AlPh3 and AlEtCl2) to formulate a series of Mg2+ electrolytes characteristic of high oxidation stability (up to 3.4 V vs Mg), sulfur compatibility and electrochemical reversibility (up to 100% coulombic efficiency). Three electrolyte systems (MgCl2-AlCl3, MgCl2-AlPh3, and MgCl2-AlEtCl2) were prepared free of purification and fully characterized by multinuclear NMR (27Al{1H} and 25Mg{1H}) spectroscopies, single crystal X-ray diffraction, and electrochemical analysis. The reaction mechanism of MgCl2 and the Al Lewis acids in THF is discussed to highlight the formation of the electrochemically active [(µ-Cl)3Mg2(THF)6]+ monocation in these electrolytes. We are grateful for the financial support from the Pacific Northwest National Laboratory (PNNL)-Laboratory Directed Research and Development (LDRD) program for developing magnesium battery technology. The XRD and SEM data were collected at the Environmental Molecular Sciences Laboratory, a national scientific user facility sponsored by the DOE’s Office of Biological and Environmental Research and located at PNNL. PNNL is a multiprogram laboratory operated by Battelle Memorial Institute for the Department of Energy under Contract DE-AC05-76RL01830.

Citation: 
Liu TL, Y Shao, G Li, M Gu, JZ Hu, S Xu, Z Nie, X Chen, CM Wang, and J Liu.2014."A Facile Approach Using MgCl2 to Formulate High Performance Mg2+ Electrolytes for Rechargeable Mg Batteries."Journal of Materials Chemistry A 2(10):3430 - 3438. doi:10.1039/c3ta14825d
Authors: 
TL Liu
Y Shao
G Li
M Gu
JZ Hu
S Xu
Z Nie
X Chen
CM Wang
J Liu
Volume: 
0
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0
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0
Publication year: 
2014

Silver nanorod arrays for photocathode applications.

Abstract: 

In this study, we explore the possibility of using plasmonic Ag nanorod arrays featuring enhanced photoemission as high-brightness photocathode material. Silver nanorod arrays are synthesized by the DC electrodeposition method and their dimensionality, uniformity, crystallinity and oxide/impurity content are characterized. These Ag nanorod arrays exhibit greatly enhanced two-photon photoemission under 400 nm femtosecond pulsed laser excitation. Plasmonic field enhancement in the array produces photoemission hot spots that are mapped using photoemission electron microscopy (PEEM). The relative photoemission enhancement of nanorod array hot spots relative to that of a flat Ag thin film is found to range between 102 and 3 x 103.

Citation: 
Vilayur Ganapathy S, MI Nandasiri, AG Joly, PZ El-Khoury, T Varga, GW Coffey, B Schwenzer, A Pandey, AN Kayani, WP Hess, and S Thevuthasan.2013."Silver nanorod arrays for photocathode applications."Applied Physics Letters 103(16):Article No. 161112. doi:10.1063/1.4825262
Authors: 
Ganapathy Vilayur
MI Nasiri
AG Joly
PZ El-Khoury
T Varga
GW Coffey
B Schwenzer
A Pey
AN Kayani
WP Hess
S Thevuthasan
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0
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0
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2013

Electrochemical Kinetics and Performance of Layered CompositeCathode Material Li[Li0.2Ni0.2Mn0.6]O2.

Abstract: 

Lithium-rich, manganese-rich (LMR) layered composite cathode material Li[Li0.2Ni0.2Mn0.6]O2 has been successfully prepared by a co-precipitation method and its structure is confirmed by XRD characterization. The material delivers a high discharge capacity of 281 mAh g-1, when charged and discharged at a low current density of 10 mA g-1. However, significant increase of cell polarization and decrease of discharge capacity are observed at voltages below 3.5 V with increasing current densities. Galvanostatic intermittent titration technique (GITT) analysis demonstrates that lithium ion intercalation/de-intercalation reactions in this material are kinetically controlled by Li2MnO3 and its activated MnO2 component. The relationship between the electrochemical kinetics and rate performance as well as cycling stability has been systematically investigated. High discharge capacity of 149 mAh g-1 can be achieved at 10 C charge rate and C/10 discharge rate. The result demonstrates that the Li2MnO3 based material could withstand high charge rate (except initial activation process), which is very promising for practical applications. A lower discharge current density is preferred to overcome the kinetic barrier of lithium ion intercalation into MnO2 component, in order to achieve higher discharge capacity even at high charge rates.

Citation: 
Zheng J, W Shi, M Gu, J Xiao, P Zuo, CM Wang, and J Zhang.2013."Electrochemical Kinetics and Performance of Layered CompositeCathode Material Li[Li0.2Ni0.2Mn0.6]O2."Journal of the Electrochemical Society 160(11):A2212-A2219. doi:10.1149/2.090311jes
Authors: 
J Zheng
W Shi
M Gu
J Xiao
P Zuo
CM Wang
J Zhang
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0
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0
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2013

Directly correlated transmission electron microscopy and atom probe tomography of grain boundary oxidation in a Ni-Al binary

Abstract: 

Intergranular oxidation of a Ni-4Al alloy exposed to hydrogenated, high-temperature water was characterized using directly correlated transmission electron microscopy and atom probe tomography. These combined analyses revealed that discrete, well-separated oxides (NiAl2O4) precipitated along grain boundaries in the metal. Aluminum was depleted from the grain boundary between oxides and also from one side of the boundary as a result of grain boundary migration. The discrete oxide morphology, disconnected from the continuous surface oxidation, suggests intergranular solid-state internal oxidation of Al. Keywords: oxidation; grain boundaries; nickel alloys; atom probe tomography; transmission electron microscopy (TEM)

Citation: 
Schreiber DK, MJ Olszta, and SM Bruemmer.2013."Directly correlated transmission electron microscopy and atom probe tomography of grain boundary oxidation in a Ni-Al binary alloy exposed to high-temperature water."Scripta Materialia 69(7):509-512. doi:10.1016/j.scriptamat.2013.06.008
Authors: 
DK Schreiber
MJ Olszta
SM Bruemmer
Instruments: 
Volume: 
69
Issue: 
7
Pages: 
509-512
Publication year: 
2013

Controlled Nucleation and Growth Process of Li2S2/Li2S in Lithium-Sulfur Batteries.

Abstract: 

Lithium-sulfur battery is a promising next-generation energy storage system because of its potentially three to five times higher energy density than that of traditional lithium ion batteries. However, the dissolution and precipitation of soluble polysulfides during cycling initiate a series of key-chain reactions that significantly shorten battery life. Herein, we demonstrate that through a simple but effective strategy, significantly improved cycling performance is achieved for high sulfur loading electrodes through controlling the nucleation and precipitation of polysulfieds on the electrode surface. More than 400 or 760 stable cycling are successfully displayed in the cells with locked discharge capacity of 625 mAh g-1 or 500 mAh g-1, respectively. The nucleation and growth process of dissolved polysulfides has been electrochemically altered to confine the thickness of discharge products passivated on the cathode surface, increasing the utilization rate of sulfur while avoiding severe morphology changes on the electrode. More importantly, the exposure of new lithium metal surface to the S-containing electrolyte is also greatly reduced through this strategy, largely minimizing the anode corrosion caused by polysulfides. This work interlocks the electrode morphologies and its evolution with electrochemical interference to modulate cell performances by using Li-S system as a platform, providing different but critical directions for this community.

Citation: 
Zheng J, M Gu, CM Wang, P Zuo, PK Koech, J Zhang, J Liu, and J Xiao.2013."Controlled Nucleation and Growth Process of Li2S2/Li2S in Lithium-Sulfur Batteries."Journal of the Electrochemical Society 160(11):A1992-A1996. doi:10.1149/2.032311jes
Authors: 
J Zheng
M Gu
CM Wang
P Zuo
PK Koech
J Zhang
J Liu
J Xiao
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0
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0
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0
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2013

The Role of Reducible Oxide-Metal Cluster Charge Transfer in Catalytic Processes: New Insights on The Catalytic Mechanism of CO

Abstract: 

To probe metal particle/reducible oxide interactions Density Functional Theory based Ab Initio Molecular Dynamics studies were performed on a prototypical metal cluster (Au20) supported on reducible oxides (rutile TiO2(110)) to implicitly account for finite temperature effects and the role of excess surface charge in the metal oxide. It was found that the charge state of the Au particle is negative in a reducing chemical environment whereas in the presence of oxidizing species co-adsorbed to the oxide surface the cluster obtained a net positive charge. In the context of the well known CO oxidation reaction, charge transfer facilitates the plasticization of Au20 which allows for a strong adsorbate induced surface reconstruction upon addition of CO leading to the formation of mobile Au-CO species on the surface. The charging/discharging of the cluster during the catalytic cycle of CO oxidation enhances and controls the amount of O2 adsorbed at oxide surface/cluster interface and strongly influences the energetics of all redox steps in catalytic conversions. A detailed comparison of the current findings with previous studies is presented and generalities about the role of surface-adsorbate charge transfer for metal cluster/reducible oxide interactions are discussed.

Citation: 
Wang Y, Y Yoon, VA Glezakou, J Li, and RJ Rousseau.2013."The Role of Reducible Oxide-Metal Cluster Charge Transfer in Catalytic Processes: New Insights on The Catalytic Mechanism of CO Oxidation on Au/TiO2 from Ab Initio Molecular Dynamics."Journal of the American Chemical Society 135(29):10673-10683. doi:10.1021/ja402063v
Authors: 
Y Wang
Y Yoon
VA Glezakou
J Li
RJ Rousseau
Instruments: 
Volume: 
135
Issue: 
29
Pages: 
10673-10683
Publication year: 
2013

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