Agenda

Title: Diffraction Microstructure Imaging 

Darren C. Pagan – Materials Science and Engineering – Penn State University 

This presentation will provide an introduction and overview of Diffraction Microstructure Imaging (DMI). Diffraction Microstructure Imaging is a range of techniques, recently recognized by the International Union of Crystallography, associated with diffraction-based 3D reconstructions of microstructure. In this presentation, I will give a broad overview of these diffraction-based techniques including high-energy X-ray diffraction microscopy, Laue microdiffraction, and energy dispersive diffraction, along with their applications to the study of engineering alloys and ceramics. Frontiers of these techniques including coherent imaging techniques, utilization of machine-learning for data analysis, and application to geological materials will also be discussed. 

Title: Complementary Beamlines at the Sirius Synchrotron for Research on Soil Phosphorus 

Dean Hesterberg – Brazilian Synchrotron Light Laboratory (LNLS-CNPEM) 

The 4th generation Sirius synchrotron source at LNLS is designed with multiple beamlines that provide scattering, imaging, and spectroscopy capabilities spanning length scales from angstroms to centimeters. This presentation will highlight complementary capabilities of selected Sirius beamlines that will be particularly useful for studying agricultural systems, and specifically the problem of inefficient phosphorus fertilization in tropical soils. The high intensity, highly coherent X-rays produced at Sirius generally allow rapid (seconds to minutes) analysis of typical samples on various beamlines. MOGNO is a hard X-ray zoom tomography beamline with fields of view ranging from 8.5 cm to 150 µm with corresponding spatial resolutions of 55 µm to 120 nm. These characteristics are useful for 3D imaging of soil macro and microstructure, and root growth. CATERETÊ is a coherent scattering imaging beamline for high-resolution (~10 nm), full field imaging of micro and nano structure within soil samples of <30 µm, or ptychography of larger samples. The CARNAÚBA beamline is a sophisticated imaging, tomography, and spectroscopy beamline covering an energy range from 2 to 15 keV, which includes the phosphorus K-edge, with target beam spot sizes from 150 to 30 nm. Multiple detectors placed around a sample provide spatially resolved 2D or 3D chemical imaging and diffraction capabilities in either transmission (STXM) or fluorescence (µ/n-XRF) modes, as well as ptychography. A high-stability monochromator adds speciation analysis by µ/n-X-ray absorption spectroscopy (XAS). The PAINEIRA beamline will provide powder X-ray diffraction in either high-throughput or high-resolution modes, which is promising for upscaling molecular to microscale information into better phosphorus management strategies based on critical mineralogical analysis of agricultural soils. Collectively, these beamlines provide both physical and chemical information on geochemical samples across a range of scales to define mechanisms of hierarchical soil processes leading to phosphorus inefficiencies.  

Title: Synchrotron X-ray Analysis in Plant Nanobiotechnology 

Gregory V. Lowry 

Walter J. Blenko, Sr. Professor of Civil & Environmental Engineering 

Carnegie Mellon University 

Pittsburgh, PA 15213, USA – September 20, 2021 

Engineered nanomaterials have shown significant promise for increasing the sustainability of agriculture. However, the physicochemical and biological properties controlling the uptake, translocation, and targeting of engineered nanomaterials in crop plants are not yet established. Synchrotron X- ray methods such as fluorescence spectroscopy, XANES mapping, and tomography are all needed to elucidate the mechanisms affecting uptake through leaves, translocation to through the plants, targeting to desired organelles, and targeting to external plant features such as stomatal guard cells. This presentation will describe recent progress towards identifying these mechanisms, focusing on the opportunities for synchrotron-based X-ray methods. 

Title: Transmission X-ray Microscopy of Li-ion Battery Anodes 

Johanna Nelson Weker

Hard X-ray transmission X-ray microscopy (TXM) is an ideal tool for in situ and operando studies of functional materials and materials synthesis routes. The high energy X-rays provides relatively relaxed restrictions on in situ environments enabling high resolution 2D microscopy and tomography across a large range of pressures and temperatures and in varying gas or liquid environments. The full field geometry of TXM allows imaging at the sub-second time scale, allowing relevant dynamics to be captured during; for example, battery cycling, catalysis reactions, electrochemical synthesis, and corrosion. Moreover, by tuning the incident X-ray energy to specific absorption edges, TXM can capture elemental and chemical (spectro-microscopy) changes at 30 nm resolution within a few minutes.  

Li-ion batteries promise the high specific capacity required to replace the internal combustion engine with a number of possible earth abundant electrode materials; however, setbacks such as capacity fading hinder the full capability of these rechargeable batteries. In the search for better electrode materials, high resolution X-ray microscopy during typical battery operation is vital in understand and overcoming the failure mechanisms of these materials. I will discuss the use of X-ray microscopy including spectro-microscopy and nano-tomography to track electrochemical and morphological changes in the electrode material in real time during typical battery operation. Specifically, I will present recent work on using X-ray microscopy to study nanoporous architectures for alloying anode to accommodate their large volume changes. I will also show recent work on imaging the chemistry of nanostructured conversion anodes.  

Title: Bragg coherent X-ray diffraction for a look inside nanostructures: interface & catalysis 

M.-I. Richard1,2,*, M. Dupraz1,2 , N. Li11,2 J. Carnis3,2,5, L. Wu2,3, S. Labat3, S.J. Leake2, L. Gao4, J.P. Hofmann4, S. Fernández2,3, M. Sprung5, A. Resta6, T.U. Schülli2, E.J.M Hensen4, O. Thomas3 

1 Univ. Grenoble Alpes, CEA Grenoble, IRIG/MEM/NRS, 17 rue des Martyrs 38000 Grenoble, France 

2ID01/ESRF, The European Synchrotron, 71 Avenue des Martyrs, Grenoble 38043 Cedex, France, 

3Aix Marseille Université, CNRS, Université de Toulon, IM2NP UMR 7334, 13397, Marseille, France 

4Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, P. O. Box 513, 5600MB Eindhoven, The Netherlands 

5PETRA III, Deutsches Elektronen-Synchrotron (DESY), D-22607 Hamburg, Germany 

6Synchrotron SOLEIL, L’Orme des Merisiers, Saint-Aubin, BP 48, Gif-sur-Yvette 91192, France 

mrichard@esrf.fr 

Characterising the structural properties (strain gradients, chemical composition, crystal orientation and defects) inside nanostructures is a grand challenge in materials science. Bragg coherent diffraction imaging (Bragg CDI) can be utilised to address this challenge for crystalline nanostructures. A resolution of the structural properties of less than 10 nm is achieved up-to-date [1–3]. The capabilities of the Bragg CDI technique will be demonstrated on single nanoparticles for enhanced catalysis.  

As an example, the Bragg CDI technique [4,5] allows understanding the interplay between shape, size, strain, faceting [5], composition and defects at the nanoscale. We will demonstrate that Bragg CDI on a single particle model catalyst makes it possible to map its local strain/defect field and directly image strain build-up close to the facets. We will also show results obtained during in situ [6-9] and operando Bragg CDI measurements: it was possible to track a single particle in gas or liquid phase environments to monitor its facet changes and to measure its strain/defect response to reaction. This technique opens pathways to determine and control the internal structure of nanoparticles to tune and optimise them during catalytic and other chemical reactions.  

Finally, we will present results from the use of a convolutional neural network [10] and from the EBS-ESRF Upgrade. 

[1] I. Robinson and R. Harder, Coherent X-Ray Diffraction Imaging of Strain at the Nanoscale, Nat Mater 8, 291 (2009). 

[2] S. Labat, M.-I. Richard, M. Dupraz, M. Gailhanou, et al., Inversion Domain Boundaries in GaN Wires Revealed by Coherent Bragg Imaging, ACS Nano 9, 9210 (2015). 

[3] N. Li, S. Labat, S. J. Leake, et al., Mapping Inversion Domain Boundaries along Single GaN Wires with Bragg Coherent X-Ray Imaging, ACS Nano 14, 10305 (2020). 

[4] J. Carnis, L. Gao, S. Labat, et al., Towards a Quantitative Determination of Strain in Bragg Coherent X-Ray Diffraction Imaging: Artefacts and Sign Convention in Reconstructions, Sci Rep 9, 1 (2019). 

[5] N. Li, M. Dupraz, L. Wu, et al., Continuous Scanning for Bragg Coherent X-Ray Imaging, Sci Rep 10, 12760 (2020). 

[6] M.-I. Richard, S. Fernández, et al., Crystallographic Orientation of Facets and Planar Defects in Functional Nanostructures Elucidated by Nano-Focused Coherent Diffractive X-Ray Imaging, Nanoscale 10, 4833 (2018). 

[7] M.-I. Richard, S. Fernández, et al., Reactor for Nano-Focused X-Ray Diffraction and Imaging under Catalytic in Situ Conditions, Review of Scientific Instruments 88, 093902 (2017). 

[8] S. Fernández, L. Gao, J. P. Hofmann, et al., In Situ Structural Evolution of Single Particle Model Catalysts under Ambient Pressure Reaction Conditions, Nanoscale 11, 331 (2019). 

[9] M.-I. Richard, S. Fernández, J. P. Hofmann, et al., Reactor for Nano-Focused X-Ray Diffraction and Imaging under Catalytic in Situ Conditions, Review of Scientific Instruments 88, 093902 (2017). 

[10] J. Carnis, et al., Twin boundary migration in an individual platinum nanocrystal during catalytic CO 

oxidation, Nat. Commun., accepted (2021). 

[11] B. Lim, E. Bellec, M. Dupraz, S. Leake, et al., A Convolutional Neural Network for Defect Classification in Bragg Coherent X-Ray Diffraction, Npj Comput Mater 7, 1 (2021). 

Title: Towards Correlative X-Ray Nanoscopy of Solar Cells at Diffraction-Limited Storage Rings 

Michael E. Stuckelberger – Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany – Contact: michael.stuckelberger@desy.de 

Today, we are utilizing scanning X-ray microscopy to answer questions about photovoltaic materials such as: How do interfaces look like in solar cell stacks? How can perovskite semiconductors be manufactured without sacrificing the efficiency due to lateral inhomogeneity? Which defects limit the device performance, and how can they be engineered to be less detrimental? How can solar cells be cost-effectively fabricated using abundant and non-toxic materials? 

Based on experiments at DESY, APS, ESRF, and NSLS II, we will showcase examples of multimodal scanning X-ray microscopy measurements during in-situ growth and operation of solar cells, involving X-ray beam induced current (XBIC) and voltage (XBIV), X-ray fluorescence (XRF), X-ray diffraction (XRD), ptychography, and X-ray excited optical luminescence (XEOL). We have found correlations between the optical / electrical performance, composition, and strain, and will highlight the relevance of X-ray microscopy for the solar cell development. Beyond photovoltaics, we will showcase applications of multi-modal X-ray microscopy to the wider area of energy research. 

Tomorrow, the questions will be different, and we will be able to use X-ray nanoscopes at diffraction-limited storage rings to answer them. Where will be the frontiers of scanning X-ray microscopy for in-situ and operando energy research? Which challenges arise with the new opportunities, and how can we tackle them? We will present ideas of ‘dream experiments’ and discuss the challenges related to multimodal scanning X-ray microscopy. 

Title: We mustbe ready to fullyexploit x-rays nanoprobes in (photo)electrocatalysis!

Pablo S. Fernández

¹ Chemistry Institute, State University of Campinas, 13083-970, Campinas, SP, Brazil.

² Center for Innovation on New Energies, University of Campinas, 13083-841 Campinas, SP, Brazil.

pablosf@unicamp.br

Electrocatalysis is a sub-field of electrochemistry where an electrochemical reaction is carried out with the help of a catalysts. In some cases, mainly in the presence of semiconductors, the reaction can be also promoted by irradiating the electrode with UV-vis light.

(Photo)electrochemical systems playsand will play a key role in the transition for a more sustainable energy transition as they have a significative importance for the energy conversion and storage. Among many applications, we can mention sensors, batteries (why not), fuel cells and electrolyzers.

Materials used in these applications have been studied for decades, however, the measured (photo)electrocatalytic response of an electrode made by nanoparticles is a consequence of the signals coming from the many particles that compose the electrode. Since the electrochemical performance is dependent on the composition, morphologyand distributionon the support, and real electrodes are intrinsically heterogeneous,it is difficult to connect these parameters with performance using conventional techniques.

In this context, a nanoprobe beamline will certainly help to decouple the contributions coming from regions containing particles with different compositions, morphologies, and distributions. Thus, we will be able to understand, from a microscopic point of view, trends inactivity, selectivity and stability, thus paving the way for the development of materials with higher performances.

In this talk,I will start explaining the ensemble averaging problem in (photo)(electro)catalysis. Then, I will highlight some cases of success that have made us to envisage a promissory future for our field using nanoprobe beamlines. Finally, I will end showing the developments in instrumentation for experiments in situ in (photo)electrocatalysis at the Carnauba beamline.

Title: Scanning SAXS imaging of biological cells 

Koester, Sarah – sarah.koester@phys.uni-goettingen.de 

X-rays provide high resolution due to their small wavelength and high penetration power, allowing for imaging of comparatively large, three-dimensional objects. For these reasons, X-rays have been established as complementary probes for bio-imaging, in addition to well-established methods such as visible light fluorescence microscopy and electron microscopy (EM). Scanning small angle X-ray scattering (SAXS), in particular, is well suited for systems with some degree of order, such as bundles of parallel filaments, or high-density aggregates. The method exploits two unique features of X-ray imaging: not only are highly focused beams used to spatially resolve different constituents of biological cells, but each individual scattering pattern contains a wealth of information about the internal structure on molecular length scales. I will present scanning SAXS experiments that were performed at dedicated synchrotron beamlines,  which provide a small beam between 100 nm and 2 µm in diameter, high flux, high-end pixel detectors and a sample environment suitable for cell samples. I will summarize the most important results we recently obtained on different biological systems, such as components of the cytoskeleton and the DNA in the nucleus. 

Title: Multiphase Flow in Porous media: How Imaging has Improved Our Fundamental Understanding 

Steffen Berg – Shell Global Solutions International B.V., Amsterdam, The Netherlands, steffen.berg@shell.com 

Transport of fluids in porous media is ubiquitous and relevant for many applications in science and technology. In most of these applications, transport is described at a continuum level using Darcy’s law where the properties of the porous medium are described with effective material parameters such as porosity and permeability, accounting in an effective manner for the flow that occurs in every individual pore which is subject to the established law of hydrodynamics.

While for single-phase flow, Darcy’s law can be derived from upscaling Stokes flow at the pore scale to the continuum level in a rigorous manner, for multiphase flow such an upscaling does currently not exist. Most approaches are phenomenological. That has the disadvantage that the respective material parameters need to be either measured or computed by pore scale simulation of multiphase flow. The choice of physical model and computational approach requires validation against experimental data. And there is the hope to progress towards a more rigorous upscaling method. In the past years the advances in 3D imaging technology, in particular synchrotron beamline-based fast X-ray computed micro tomography has led to a significant increase in understanding and to a significant progress of the whole research domain.  

One example is the topic of capillary pressure hysteresis where imaging has significantly contributed to bring this long-standing problem finally to a convincing solution. At the Darcy scale many parameters describing multiphase flow in porous media are hysteretic, such as the capillary pressure and relative permeability saturation functions. In particular for the capillary pressure-saturation function the source of the hysteresis has been an open question in many disciplines such as petroleum engineering and hydrology. Synchrotron beamline based fast X-ray computed micro-tomography has led to the insight that topological changes are the source of the hysteresis. It was demonstrated that the capillary pressure hysteresis is only apparent and a consequence of an incomplete set of state variables. The state variables are essentially the 4 Minkowski functionals which are (1) volume or saturation, (2) interfacial area, (3) mean curvature which is related by the interfacial tension to capillary pressure, and (4) the integral Gaussian curvature which is related via the Gauss-Bonnet theorem to the Euler characteristic. For systems with partial wetting, the Gauss-Bonnet theorem includes the additional geodesic curvature term, which can be interpreted as deficit curvature and related to contact angle. Under equilibrium conditions Young’s equation for contact angle can be derived from this topological description is a universal formulation and Young’s equation. That provides a significant advancement for describing capillary systems in complex geometries in more general. 

To advance the field further and address problems of great societal relevance such as transport in gas diffusion layers of fuel cells, underground hydrogen storage and many more, imaging could significantly contribute by resolving pore scale flow and concentration fields, and map chemical heterogeneity of the solid.  

Title: From Nanopores to Reservoirs: an important scientific trajectory for the improvement of Petroleum Exploration and Production 

Due to the significant efforts of several research groups, we are building a collaborative network involving multidisciplinary expertise dedicated to the study of fluid dynamics in porous rock media. This initiative covers geology, geophysics, physics, chemistry, biology, computer science, and engineering, among other perspectives, emphasizing oil reservoir rocks. To carry out the collaborative research, we have carefully chosen natural and synthetic reservoir rocks so that they can be studied with various experimental techniques, which analyze both the porous media (e.g., 3D structure and mineralogical composition) and the fluids that permeate them (“static” or under controlled flow regime).  This information serves as input data for multiscale numerical simulations (in time and space), allowing a better understanding of Oil Exploration and Production. In this talk, we will present some of the theoretical, experimental, and computational techniques used and the results already achieved, highlighting those obtained with Nuclear Magnetic Resonance. 

Title: Multi-modal scanning probe microscopy on functional materials 

Xiaojing Huang – National Synchrotron Light Source II, Brookhaven National Laboratory, Upton NY 11973 USA 

The penetration power and high energy of X-rays enable a suite of analytic tools for materials characterization. The Hard X-ray Nanoprobe beamline at the National Synchrotron Light Source II focuses the X-ray beam to a 12 nm spot, and measures fluorescence, transmitted scattering and Bragg diffraction signals from the specimen at each scan position. This multi-modality operation mode investigates chemical, morphological and crystalline properties simultaneously, thus gives a comprehensive picture of the sample under study. In this presentation, we will show examples of applying this technique on studying energy storage materials systems. We will also discuss the challenges on achieving high resolution from a thick sample volume, and present potential solutions by extending the depth of field.