Report
Teaser, summary, work performed and final results
Periodic Reporting for period 1 - TOP (Towards the Bottom of the Periodic Table)
Teaser
The general goal of the TOP project is to advance the fundamental understanding of lanthanide (Ln) and actinide (An) oxide nanoparticles (NPs), and to review the real-life processes in which these systems play an important role. The valence electrons in Ln and An occupy f...
Summary
The general goal of the TOP project is to advance the fundamental understanding of lanthanide (Ln) and actinide (An) oxide nanoparticles (NPs), and to review the real-life processes in which these systems play an important role.
The valence electrons in Ln and An occupy f orbitals, making them chemically and physically different from the other elements in the periodic table. This difference includes such basic properties as their oxidation state, electronic configuration, use of f-orbitals in bonding and their interaction with ligands. The challenges continue to mount when Ln and An ions are present in nanometre dimensions in functional materials, devices and environments in the form of nanoparticles, nanorods, nanowires, nanotubes and nanoclusters. Nanotechnology urgently needs to understand and to take advantage of nanomaterial properties in an innovative and controllable way. Once the properties of nanostructures are characterized and understood well and can be reproducibly fabricated, those properties can be exploited as a technology. The behaviour of the 4f/5f electrons in An/Ln systems dictates their characteristic performance. Probing the behaviour of the electrons necessarily employs experimental techniques that are non-destructive and bulk sensitive to the sample being studied. Synchrotron X-rays are ideal for obtaining the electronic and structural information of exotic materials, contained f-block elements.
The research related to the current ERC project is conducted at a large scale facility: the European Synchrotron (ESRF) at the Rossendorf Beamline (ROBL). This innovative, recently installed experimental setup – an X-ray emission spectrometer - with ground-breaking detection limits is used to obtain exclusive experimental data through high energy resolution fluorescence detection (HERFD) X-ray absorption spectroscopy and resonant inelastic X-ray scattering (RIXS) methods.
To summarize, this project will address the problems related to the formation of the Eu, Ce, U, Th and Pu colloidal NPs, occurring both naturally and synthesised artificially, and will provide new results to advance this challenging topic. The project will contribute to interdisciplinary development of the collaboration between experimentalists in the fields of X-ray spectroscopy and theorists by comparing electronic structure calculations to high energy precision experimental data. As a long-term impact, nanotechnology will gain the ability to affect materials and structures of complex systems that can potentially influence actions of nanomaterials in applications, which is relevant to materials science, biology, medicine, photochemistry and environmental science technology.
Work performed
\"Fundamental properties of An and Ln nanomaterials have been studied at the ESRF by HERFD and RIXS methods. One postdoctoral fellow (Stephen Bauters) was employed for the installation, commissioning and software development of the X-ray emission spectrometer. The experimental setup is installed, testes and was available for use since the beginning of the project. We studied CeO2, UO2 and PuO2 NPs made by various synthesis routes, in different size. Experimental data on NPs compared to their bulk analogues. One postdoctoral fellow (Ivan Pidchenko) was employed to set-up the laboratory for the NPs synthesis at the host institute - HZDR. Coupling of the experimental information to the electronic structure calculations helped to understand the Ln/An performance in different systems. One postdoctoral fellow (Lucia Amidani) was employed to accurately model the experimental data . Additionally, one PhD student (Evgeny Gerber) was employed in the terms of ERC project from the beginning of the project. He is working in close collaboration with three postdoctoral fellows on studies of Ce, U, Th, Pu oxide nanoparticles. Two MS students joint the group for 6 and 5 months periods. Their projects, dedicated to the three-dimensional analysis of actinide minerals by confocal X-ray micro fluorescence imaging (Irina Sinenko) and theoretical investigation of the electronic structure of uranium systems at the U M4,5 edges (Anna Volkova).
The achieved results are partially published (5 publications), two papers are under review and three more papers are submitted. All scientific results were shown at the scientific meetings, conferences and workshops, listed below:
Evgeny Gerber (PhD student) was awarded a medal for the \"\"best young researcher\'s oral presentation\"\" at the 48th Journees de Actinides (JDA) in Portugal in 2018.
2018- 12th School on the Physics and Chemistry of the Actinides (12th SPCA), Bobadela, Portugal
2018 - XAFS17 in Krakow, Poland (oral presentation)
2018 - Plutonium Futures–The Science 2018 in San-Diego, USA (oral presentation)
2019 - RAD 2019 Conference in Herceg Novi, Montenegro (oral presentation)
2019 - School and Conference on Analysis of Diffraction Data in Real Space (ADD 2019)in Grenoble, France
2019 - visited and established collaboration with CEA in Marcoule, France (oral presentation)
2019 - Crystal structure refinement with Jana2006 course in Jena, Germany
Ivan Pidchenko (Postdoc):
2018 - RadChem conference, Marianske Lazne, Czech Republic
2018 - Visited and established collaboration with Leibniz University Hannover, Germany
2018 - Goldschmidt conference, Boston, USA, August 2018, (Poster presentation)
2018 - Training (1 month) at the Center for Sustainable Energy at Notre Dame (USA)
2019 - Visited and established collaboration with European Commission, Joint Research Centre, Karlsruhe, Germany
2019 - Workshop at HZDR (oral presentation)
Lucia Amidani (Postdoc):
2018 - Visited and established collaboration with Charles University, Prague, Czech Republic
2018 - XAFS17 in Krakow, Poland (oral presentation)
2018 - Quanty workshop in Heidelberg, Germany
2019 - visited and established collaboration with CEA in Marcoule, France
2019 - Workshop at HZDR (oral presentation)
2019 - Inivited talk at UGA, Grenoble
2019 - JdA 2019 conference in Erice, Italy (oral presentation)
2019 - EMRS conference in Nice, France (oral presentation)
Stephen Bauters (Postdoc):
2018 - HZDR workshop (oral presentation)
2019 - Visited and established collaboration with University of Helsinki (oral presentation)
Irina Sinenko (MS student):
2018 - Nuclear Waste Materials Summer School, Dresden, Germany (poster presentation)
Kristina Kvashnina (PI):
2018 - 48th Journees de Actinides (JDA) in Portugal
2018 - MINATEC les Midis public talk in Grenoble, France (300 participants)
2018 - ATAS workshop in Nice, France (oral presentation)
2019 - EMRS conference in Nice, France (oral presentation)
We organized a workshop dedicated to the nuclear prob\"
Final results
The original plan was to perform experimental investigations of mineral phases containing naturally occurring An/Ln NPs and bulk/reference An/Ln materials and proceed with investigations of synthetic An/Ln NPs at the end of the project (period: 36-60 months). The main plan was to study Eu, Ce, U and Th containing materials from the beginning and go towards studies of Pu containing systems at the end of the project. However, from the beginning of the project we studied minerals and all An/Ln elements: U, Ce, Eu, Th and Pu in various nanosystems. The reason for that was a foreseen shutdown period of ESRF. We were able to conduct 18 experiments and to collect a great set of data. Thanks to the alpha laboratory at HZDR, available for An synthesis and availability of U, Th, and Pu species for the investigations.
Ivan Pidchenko was able in a really short period to set-up the laboratory and to develop special setups: 1) In-situ electrochemical cell for An amd 2) Setup for preparation of nanocrystalline samples with controlled stoichiometry and nanocrystal size (Images are attached here). The first setup - In-situ spectro-electrochemical cell for preparation of actinides (Th, U, Np, Pu) with various oxidation states. It has the ability for in-situ observation of colloidal Pu (oxyhydr)oxide species formation. Cell can be combined with auto-titration setup for more controlled conditions for colloids preparation and allows for controlled aliquots with a peristaltic pump or adjusting the cell for other experiments, i.e. sorption, co-precipitation experiments. The second setup is for controlled preparation of nanocrystalline (nc)-UO2+x, (U,Ln3+)O2+x and (U,An3/4+)O2+x species. Built-in electrochemical setup allows for controlling stoichiometry of U and auto-titration unit maintains desired nc cluster size by varying pH of aqueous solution with low pH drifts (±0.01 pH unit).
Additionally, the original plan was to use laboratory available instrumentation at HZDR for per-characterization of nanomaterials and use HERFD/RIXS methods at the synchrotron for studies of the investigated materials. However, we went beyond those plans and additionally explored new state-of-the-art methods available at the ESRF, like XRD, PDF, XRF, SAXS/WAXS. Thanks to the great help of safety groups at HZDR and ESRF who allowed to perform such investigations.
Regarding the HERFD/RIXS methods and X-ray emission spectrometer, the progress went beyond the original plans. Staff of the TOP group created a special software, named PyXES. Our in-house developed open source PyXES program combines elemental information, experimental control and data analysis in one state-of-the-art interactive environment (Image attached). It contains a large library of tabulated values concerning elemental absorption edges, fluorescent energies and provides information about which crystals are best suited for each experiment in just a few clicks. The link between PyXES and the spectrometer allows for direct motorized control, enabling straightforward alignment procedures. A sequence builder grants the user full experimental control, easily combining HERFD, XES and RIXS scans with sample positioning and other experimental parameters such as heating and beamline control. The integrated plotting module is capable of both visualising live measurements as well as analysing the recorded data afterwards, encapsulating a whole spectrometer experiment within one user-friendly program. Our PyXES Program has been already installed and used at 4 other places: Soleil Synchrotron (France), 2 beamlines at ESRF, The Australian Synchrotron.
Additionally, the host institute - HZDR - invested about 300 000 EUR in crystal analyzers for X-ray emission spectrometer. It allows to use X-ray emission spectrometer in other fields (not only in investigations of the f-electron systems) and to study most of elements in periodic table in high energy resolution mode. Therefore, instrument is available for researcher
Website & more info
More info: https://www.hzdr.de/db/Cms.