Understanding how nanoparticles interact is key to improve metal nanocatalysts

Nanocatalysts are key for the future of sustainable chemistry, yet, they typically suffer from rapid deactivation caused by a process called sintering. In a recent study led by the ALBA Synchrotron and Ghent University, researchers have developed an integrated approach where they complement the use of several characterization techniques to study platinum nanoparticle sintering at the micro-, meso- and macroscale. The demonstrated approach shows that mesoscale heterogeneities in the nanoparticle population drive sintering. This work will help broaden the fundamental understanding of nanoparticle sintering and thus design better strategies for catalyst fabrication.

Metal nanoparticle catalysts are the workhorses in a broad range of industrially important chemical processes such as producing clean fuels, chemicals and pharmaceuticals or cleaning exhaust from automobiles. These nanocatalysts are key for the future of sustainable chemistry, yet they typically suffer from rapid deactivation caused by a process called sintering. Due to sintering, the average nanoparticle size increases since this is energetically more efficient for the nanoparticles. However, this decreases their catalytic power.

To date, sintering phenomena are analyzed either at the macroscale, to examine averaged nanoparticle properties, or at the microscale, studying individual nanoparticles. However there is a knowledge gap on the nanocatalysts behavior at the mesoscale, the intermediate length scale between the macro and the micro worlds. At the mesoscale, large ensembles with thousands of nanoparticles can be studied as a “population” in which nanoparticles “communicate” – interact – with each other. In this context, nanoparticle sintering can be considered as a dynamic population of interacting nanoparticles, each of them trading and exchanging atoms to gain stability within the nanoparticle hierarchy.

In a recent study led by the ALBA Synchrotron and Ghent University, researchers have developed an integrated approach where they complement the use of several characterization techniques to study platinum nanoparticle sintering at the micro-, meso- and macroscale. More specifically, they used different analytical techniques and X-ray scattering characterization at the NCD-SWEET beamline in ALBA to show that mesoscale heterogeneities in the nanoparticle population drive sintering. Thus, deleting these heterogeneities would help to avoid sintering.

Read more on the ALBA website

Image: Researchers inside the experimental hutch of the NCD-SWEET beamline at the ALBA Synchrotron. From left to right: Zhiwei Zhang (Ghent University), Matthias Minjauw (Ghent University), Matthias Filez (Ghent University – KU Leuven) and Juan Santo Domingo Peñaranda (Ghent University).

2023 Young Scientist Award winner announced

Dr Elke de Zitter, from the Institut de Biologie Structurale (IBS) in Grenoble, is the winner of the European XFEL Young Scientist Award 2023. The price was awarded today at the Users’ Meeting 2023 by Andrea Eschenlohr, chairwomen of the European XFEL User Organisation Executive Committee. De Zitter’s research focuses on processing serial-crystallography data taken by the SPB/SFX instrument at European XFEL. She is interested in mosquitocidal proteins, that target and kill mosquitos, the deadliest animal on Earth because of the diseases they carry. She has also worked on developing a piece of software known as Xtrapol8 which can extract protein structures from European XFEL data.

“The European XFEL Young Scientist Award highlights the future potential of young scientists working in X-ray laser science, outlining the talent, hard-work and dedication of the early-career researchers within our user community,” says Sakura Pascarelli, Scientific Director at European XFEL. “It is an opportunity to highlight the impact of new research done by talented young researchers, as well as to showcase the large collaborative efforts that are required for research at European XFEL.” 

Read more on the European XFEL website

ExPaNDS webinar series to showcase achievements and look to the future

We’re pleased to announce our upcoming topic-based webinars which will take place during the coming month before the end of our grant in February 2023. The webinar topics have been selected with the help of our work package leaders and some of the highlighted use cases taken directly from the PaN community throughout our grant.

The series will provide a great opportunity to showcase some of the outcomes of our grant to the PaN facility user communities. We will present some key findings from the recently conducted data consultation, which was sent to over 14,000 PaN facility users.

The ongoing work of ExPaNDS has been very important to the PaN community and we have invited senior community figures to discuss the future needs and requirements for their respective discipline or technique to keep the momentum going beyond the grant.

We will have flash talks from our work packages with focus being on FAIR, data catalogue services, data analysis and an overview of the PaN training platform.

Read more on the ExPaNDS website

Image: Chairman of the DESY Board of Directors – Professor Dr Helmut Dosch

Blood-type conversion process informed by crystallography now in pre-clinical trials

Application of a discovery that was aided in part by the Canadian Light Source (CLS) at the University of Saskatchewan has advanced to pre-clinical trials and is now the basis of a dynamic new startup.

In 2019 Dr. Stephen Withers and colleagues at the University of British Columbia identified a series of enzymes that can be used to modify the chemical structure of a sugar antigen on the surface of blood cells, thereby converting a Type A blood cell to a Type O blood cell — the universal donor type. The team used crystallography on the CMCF beamline at the CLS to better understand how the enzymes cause this change.

These same antigens are also present on the surface of solid organs, and Withers and colleagues have demonstrated that the enzymes they discovered are very efficient at making this conversion both on the surface of red blood cells and on the surface of donated human organs such as lungs or kidneys.

Avivo – the company launched to bring this technology to the marketplace – is now busy finetuning both applications. If successful, this exciting advance would be a huge step forward in addressing shortages in blood and organ supply here in Canada and around the world. “The idea is that we could broaden the supply considerably,” says Withers, a professor in the Departments of Chemistry and Biochemistry and the Michael Smith Laboratories at UBC. “It would remove the need to worry about blood type in transfusions (and organ donations).”

John Barclay, VP of business development with Avivo says the company is focusing first on applying their approach to organ donations because it’s considerably more straightforward to remove the conversion enzymes prior to transplantation than it is to remove them before transfusing blood.

When a donor organ is harvested, it will often be placed on a perfusion device that continuously pumps a preservation solution, or perfusate, through it to maintain the tissue’s viability. The enzymes discovered by the Withers team can be added to the fluid mixture, where they essentially convert the blood type of the organ to the universal blood type. After that conversion, the solution – including the enzymes — is essentially “rinsed” out of the organ as part of the existing transplant process. Removing the enzymes from red blood cells or whole blood is considerably more challenging, says Barclay.

The Avivo team has demonstrated the process works using a set of human lungs that were deemed not viable for transplanting into a patient. “We’ve shown that we can remove those antigens and convert an A type lung to an O type lung quite readily,” says Withers. “We’re working on kidneys at the moment…so that’s very exciting.”

This application of their technique is in pre-clinical trials now; they’re hoping to move on to clinical trials (i.e., in human patients) in 2024.

How the Canadian Light Source contributed

“The information we learned from it (crystallography) was very supportive in knowing exactly the structure of the enzymes we’re adding,” says Withers. This information, he says, will be very useful if they need to modify the structure of the enzyme.

It will also be valuable when they seek regulatory approval, to be able to present the complete structure of the enzymes. “We’ve learned a lot more through having that information, which may be useful in the future,” says Withers.

Read more on the CLS website

Image: Steve Withers, John Barclay, and John Coleman.

Travel the world of light sources with our 2023 calendar

Lightsources.org is a collaboration that brings together 23 synchrotrons and 7 Free Electron Lasers located at 24 member facilities around the world. Each member facility has contributed an image for our 2023 Lightsources.org calendar.

Download your digital copy below and keep up to date with news, events, job vacancies (including PhD and postdoc positions) and proposal deadlines by subscribing to our weekly newsletter here

You can get in touch with Silvana Westbury, our Project Manager, via e-mail at: webmaster@lightsources.org

Revealing the thermal heat dance of magnetic domains

Scientists invented a new way of tracking electronic properties inside materials, and used it to visualize magnetic domains in a previously unseen way.

Everyone knows that holding two magnets together will lead to one of two results: they stick together, or they push each other apart. From this perspective, magnetism seems simple, but scientists have struggled for decades to really understand how magnetism behaves on the smallest scales. On the near-atomic level, magnetism is made of many ever-shifting kingdoms—called magnetic domains—that create the magnetic properties of the material. While scientists know these domains exist, they are still looking for the reasons behind this behavior.

Now, a collaboration led by scientists from the U.S. Department of Energy’s Brookhaven National Laboratory, Helmholtz-Zentrum Berlin (HZB), the Massachusetts Institute of Technology (MIT), and the Max Born Institute (MBI) published a study in Nature in which they used a novel analysis technique—called coherent correlation imaging (CCI)—to image the evolution of magnetic domains in time and space without any previous knowledge. The scientists could not see the “dance of the domains” during the measurement but only afterward, when they used the recorded data to “rewind the tape.”

The “movie” of the domains shows how the boundaries of these domains shift back and forth in some areas but stay constant in others. The researchers attribute this behavior to a property of the material called “pinning.” While pinning is a known property of magnetic materials, the team could directly image for the first time how a network of pinning sites affects the motion of interconnected domain walls.

“Many details about the changes in magnetic materials are only accessible through direct imaging, which we couldn’t do until now. It’s basically a dream come true for studying magnetic motion in materials,” said Wen Hu, scientist at the National Synchrotron Light Source II (NSLS-II) and co-corresponding author of the study.

Read more on the Brookhaven National Laboratory website

Image: The image shows the areas where the borders of magnetic domains accumulate over time. It is similar to a photo of a traffic intersection taken at night with a long exposure time. In such a photo, we would see brighter areas along the paths that most cars’ headlights traveled. Here we see brighter areas where most domain walls come together.

MAX IV and nine Swedish universities launch joint effort to educate young scientists

PRISMAS, Ph.D. Research and Innovation in Synchrotron Methods and Applications in Sweden is launched. The programme includes hands-on training in cutting-edge synchrotron skills that is applicable in various research areas at MAX IV in Lund, Sweden. It combines practical experience with courses covering all aspects of synchrotron radiation to produce researchers who are experts in these methods and their fields. 

Students from diverse scientific backgrounds will be recruited through partner universities to learn to use and develop synchrotron methods in their research while acquiring the skills to tackle some of the most critical sustainability development goals and future societal challenges in their projects led by selected Principal Investigators from around Sweden. This 5-year intersectoral and interdisciplinary project will create a connected network of next generation X-ray experts, enabling a wider range of stakeholders to take full advantage of world-leading synchrotron facilities such as MAX IV, while tackling current societal challenges in the same breath.

Read more on the MAX IV website

Unusual compound found in Rembrandt’s The Night Watch

An international team of scientists from the Rijksmuseum, the CNRS, the ESRF the European Synchrotron, the University of Amsterdam and the University of Antwerp, have discovered a rare lead compound (named lead formate) in Rembrandt’s masterpiece The Night Watch. This discovery, which is a first in the history of the scientific study of paintings, provides new insight into 17th-century painting technique and the conservation history of the masterpiece. The study is published in Angewandte Chemie – International edition.

The Night Watch, painted in 1642 and displayed today in the Rijksmuseum Amsterdam (The Netherlands), is one of Rembrandt’s most important masterpieces and largest work of art. In the framework of the 2019 Operation Night Watch, the largest research and conservation project ever undertaken for Rembrandt’s masterpiece, an international research team joined forces to study how the painting materials react chemically and with time.

The team of scientists combined multi-scale imaging methods in order to chemically study the materials used by Rembrandt in The Night Watch. A X-ray scanning instrument developed at the University of Antwerp (Belgium) was applied directly to the painting, while tiny fragments taken from the painting were studied with synchrotron micro X-ray probes, at the ESRF, the European Synchrotron (France), and PETRA-III facility (Germany). These two types of analyses revealed the presence of an unexpected organo-metallic compound: lead formates. This compound had never been detected before in historic paintings: “In paintings, lead formates have only been reported once in 2020, but in model paintings (mock-up, fresh paints). And there lies the surprise: not only do we discover lead formates, but we identify them in areas where there is no lead pigment, white, yellow. We think that probably they disappear fast, this is why they were not detected in old master paintings until now”, explains Victor Gonzalez, CNRS researcher at the Supramolecular and Macromolecular Photophysics and Photochemistry (PPSM) laboratory (CNRS/ENS Paris-Saclay) and first author of the paper.

Read more on the ESRF website

Image: The Night Watch, Rembrandt van Rijn, 1642

Credit: Rijskmuseum Amsterdam

Building better catalysts to close the carbon dioxide loop

The best way to stave off the worst effects of climate change is to reduce CO2 emissions around the world. And one way to do that, says Zhongwei Chen, a professor in the Department of Chemical Engineering at the University of Waterloo, is to capture the CO2 and convert it into other useful chemicals, such as methanol and methane for fuels. Stopping emissions at the source, and further reducing future ones by replacing CO2-producing fuels with cleaner ones “…is a way to close the circle,” Chen says.

In order to turn CO2 into methanol, you need a catalyst to jump-start the electrochemical reaction. Traditionally, these catalysts have either been made out of precious metals like gold or palladium, or base metals like copper or tin. However, they are expensive and break down easily, hindering large-scale implementation. “Right now we can’t meet industrial requirements,” says Chen, who holds a Canada Research Chair. “So we are trying to design catalysts with better activity, selectivity, and durability.”

Read more on the CLS website

Image: Chithra Karunakaran on the SM beamline at the Canadian Light Source

Credit: David Stobbe

New simulation tool opens path to superfast electronic switches

Electronic devices operate at speeds limited by the physical processes underlying their operation: the faster the process, the quicker the information processing speed. One such fast process that might lead to the development of superfast magnetic switches is the demagnetisation of layered magnetic materials (multilayered ferromagnets) when hit by ultrafast X-ray laser pulses. This process has been poorly understood to date, but now a joint research project by European XFEL and the Institute of Nuclear Physics of the Polish Academy of Sciences (IFJ PAN) has developed a new simulation tool, taking an important step towards superfast electronics.

“In recent years, physicists have become quite familiar with demagnetisation processes initiated by visible or near-infrared light. However, when it comes to the impact of more energetic X-ray radiation, we are all just taking the first steps,” says Beata Ziaja-Motyka, initiator of the research project. “Our team’s contribution lies in the construction of a theoretical model called XSPIN. With its help, it is possible for the first time to simulate demagnetisation in multilayered ferromagnetic materials exposed to femtosecond pulses of light from an X-ray laser.”

Read more on the European XFEL website

Image: A pulse of X-ray radiation hits a sample of material with magnetic properties, scatters and forms a diffraction ring. The diameter of the ring depends on the average distance between the magnetic domains, and its intensity is the greater, the stronger the magnetization of the sample.

Credit: FJ PAN

Graphene coated nickel foams for hydrogen storage

Hybrid composites where graphene (Gr) and other 2D materials replicate the meso-and micro-structure of 3D porous substrates have shown innovative functionalities in catalysis and energy-related fields. Concerning hydrogen storage, the high surface-to-volume ratio exhibited by both 2D and 3D components of the hybrid material is expected to increase the efficiency of surface chemisorption and bulk absorption of hydrogen in comparison to the flat counterparts. To explore this possibility, we have grown single layer Gr on porous nickel foams and have investigated the interaction with H atoms as a function of the temperature by using X-ray photoelectron spectroscopy and thermal programmed desorption (TPD) at the SuperESCA beamline of Elettra.

The growth of Gr on the Ni foam was obtained by exposing the sample at 773 K to ethylene. Selected C 1s spectra taken at increasing growth time are shown in Fig.1a. Upon exposure to ethylene, the carbide phases (N1-N4 components) observed in the pristine sample disappear, while new Gr components (labeled C0 and C1) progressively increase in intensity and eventually saturate. The component C0 is attributed to GrS regions grown on the (111) foam grains, where the interaction with the support is as strong as that between Gr and the ordered Ni(111) surface; C1 is attributed to GrW regions that are rotated with respect to (111) grains, or are grown on Ni grains exposing different orientations, and therefore, are interacting weakly with the support.

Read more on the Elettra website

Figure 1: a) C 1s spectra measured during the Gr growth after 0, 3,10,16 and 44 minutes of exposure to ethylene at 773 K and (bottom) at RT after growth; b) C 1s spectra acquired on the Gr/foam hydrogenated with the same H dose at the indicated temperatures TH and c) TPD curves measured during sample annealing.

Fig. 1b shows the C 1s spectra measured on the Gr/foam exposed to a flux of H atoms at temperatures TH between 78 and 298 K. Starting from TH=98 K, the C 1s line shapes appear broadened on the high binding energy (BE) side, due to the appearance of a component (labeled A) at 285.0 eV, and also on the low BE side, due to another component (labeled B) at 284.1 eV. A and B are ascribed to C atoms directly bonded to H atoms and to their first neighbors, and therefore indicate the occurrence of H chemisorption on Gr. From 198 K, some intensity is transferred from C0 to C1, because at this temperature the H atoms start to intercalate below GrS, which detaches gradually from the substrate. The intercalation under the nearly free-standing GrW remains undetected, because here the penetration of H underneath does not cause any measurable extra-shift of the C1 component.

Fig. 1c shows H2 TPD curves measured while heating the Gr/foam hydrogenated at increasing TH. The desorption of H atoms chemisorbed on Gr originates solely the weak peak G at ~ 650 K.  Hence, all other TPD features correspond to the desorption of H atoms intercalated below Gr and residing at the Ni foam surface or even diffused into the Ni bulk. Hence, differently from GrS, where H atoms intercalate only for TH ~ 198 K, intercalation below GrW occurs at much lower temperatures. The TPD curves up to TH=173 K are dominated by the D peak, due to the desorption of H atoms penetrated in metastable subsurface sites of the Ni foam. The H2 release at higher temperatures is related to the slower desorption of bulk H atoms and to the release of H atoms chemisorbed on the Ni surface. It turns out that the highest quantity of loaded hydrogen is detected for TH= 113 K and amounts to ~ 5 times the quantity which saturates the Ni (111) surface with equivalent macroscopic lateral dimension.

#SynchroLightAt75 – Grating interferometry and phase-contrast imaging

The development of X-ray phase-contrast imaging at Paul Scherrer Institute PSI tells a story of how basic research can quickly lead to practical applications. Grating interferometry was pioneered by PSI scientists as a technique for characterizing the X-ray wave front at synchrotron sources, such as the Swiss Light Source SLS. This development enhanced the quality of X-ray images. Soon after, it began to be used for phase-contrast imaging of soft matter-like tissue, and was subsequently brought to X-ray lab sources as well. Currently, it is under development for mammography with improved contrast for soft tissue and the micro-calcifications that are markers for benign and malignant tissue alterations.

Read more about this development via these links: Phase contrast improves mammography and Phase-contrast X-ray imaging for advanced breast cancer detection

Image: Marco Stampanoni pioneered the technique of phase-contrast X-ray imaging, which enables higher resolution mammograms that can help detect breast cancer earlier

Credit: Paul Scherrer Institute / Markus Fischer

New software based on Artificial Intelligence helps to interpret complex data

Experimental data is often not only highly dimensional, but also noisy and full of artefacts. This makes it difficult to interpret the data. Now a team at HZB has designed software that uses self-learning neural networks to compress the data in a smart way and reconstruct a low-noise version in the next step. This enables to recognise correlations that would otherwise not be discernible. The software has now been successfully used in photon diagnostics at the FLASH free electron laser at DESY. But it is suitable for very different applications in science.

More is not always better, but sometimes a problem. With highly complex data, which have many dimensions due to their numerous parameters, correlations are often no longer recognisable. Especially since experimentally obtained data are additionally disturbed and noisy due to influences that cannot be controlled.

Helping humans to interpret the data

Now, new software based on artificial intelligence methods can help: It is a special class of neural networks (NN) that experts call “disentangled variational autoencoder network (β-VAE)”. Put simply, the first NN takes care of compressing the data, while the second NN subsequently reconstructs the data. “In the process, the two NNs are trained so that the compressed form can be interpreted by humans,” explains Dr Gregor Hartmann. The physicist and data scientist supervises the Joint Lab on Artificial Intelligence Methods at HZB, which is run by HZB together with the University of Kassel.

Read more on the HZB website

Ancient asteroid grains provide insight into the evolution of our solar system

The UK’s national synchrotron facility, Diamond Light Source, was used by a large, international collaboration to study grains collected from a near-Earth asteroid to further our understanding of the evolution of our solar system.

Researchers from the University of Leicester brought a fragment of the Ryugu asteroid to Diamond’s Nanoprobe beamline I14 where a special technique called X-ray Absorption Near Edge Spectroscopy (XANES) was used to map out the chemical states of the elements within the asteroid material, to examine its composition in fine detail. The team also studied the asteroid grains using an electron microscope at Diamond’s electron Physical Science Imaging Centre (ePSIC).

Julia Parker is the Principal Beamline Scientist for I14 at Diamond. She said:

The X-ray Nanoprobe allows scientists to examine the chemical structure of their samples at micron to nano lengthscales, which is complemented by the nano to atomic resolution of the imaging at ePSIC. It’s very exciting to be able to contribute to the understanding of these unique samples, and to work with the team at Leicester to demonstrate how the techniques at the beamline, and correlatively at ePSIC, can benefit future sample return missions.

The data collected at Diamond contributed to a wider study of the space weathering signatures on the asteroid. The pristine asteroid samples enabled the collaborators to explore how space weathering can alter the physical and chemical composition of the surface of carbonaceous asteroids like Ryugu.

The researchers discovered that the surface of Ryugu is dehydrated and that it is likely that space weathering is responsible. The findings of the study, published today in Nature Astronomy, have led the authors to conclude that asteroids that appear dry on the surface may be water-rich, potentially requiring revision of our understanding of the abundances of asteroid types and the formation history of the asteroid belt.

Read more on the Diamond website

Image: Image taken at E01 ePSIC of Ryugu serpentine and Fe oxide minerals.

Credit: ePSIC/University of Leicester.

Structural evidence that rodents facilitated the evolution of the SARS-CoV-2 Omicron variant

The omicron variant of COVID-19 was identified in the fall of 2021. It stood out from all of the other variants because of the many mutations that simultaneously occurred in its spike protein1. So far, surveillance and bioinformatics have been the main scientific tools in tracking COVID-19 evolution. Eventually, however, understanding COVID-19 evolution comes down to understanding the functions of key viral mutations. This is where structural biology kicks in and plays a critical role in tracking COVID-19 evolution.

In a study recently published in the journal Proceedings of National Academy of Sciences USA, Dr. Fang Li and colleagues at the University of Minnesota determined the high-resolution crystal structure of the omicron strain’s spike protein and its mouse receptor (Fig. 1A)2, using macromolecular cystallography x-ray data measured at Beam Line 12-1 of SSRL. Through detailed analysis, the researchers identified three mutations (Q493R, Q498R, and Y505H) in the omicron spike protein that are specifically adapted to two residues (Asn31 and His353) in the mouse receptor (Fig. 1B, 1C). After searching all of the available receptor sequences in the database, the researchers found that only the receptor from mice contains Asn31 and His353, while the receptors from several other rodent species contain one but not both Asn31 and His353. Thus, the researchers hypothesized that rodents, particularly mice, played a role in the omicron evolution. In contrast, these three mutations in omicron are structurally incompatible with the corresponding two residues (Lys31 and Lys353) in the human receptor (Fig.1D, 1E)2, further suggesting that non-human animal reservoirs facilitated the omicron evolution.

Read more on the SSRL website

Image: Figure 1 (C) Structural details of the omicron RBD/mouse ACE2 interface showing Arg498 and His353 in omicron RBD are both structurally adapted to His353 in mouse ACE2.

Scientists find the presence of fluids derived from subducted slab in the lower mantle

A team of scientists, led by University College Cork (Ireland) and Bayreuth Geoinstitute (Germany), has found proof of subducted slab fluids in the lower mantle by studying inclusions in diamonds using the ESRF.

In the Juína region, in the west of Brazil, a volcanic eruption brought diamonds from the interior of the Earth to the surface around 93 millions of years ago. Diamonds form perfect capsules so they retain the exact chemistry of material from the part of the Earth where they formed. Scientists are therefore studying these minerals to get information on the composition of the deep upper mantle, the transition zone and lower mantle.

Now a team led by University College Cork (Ireland) and Bayreuth Geoinstitute (Germany) has found that subducted material has penetrated into the sublithosperic mantle (below 250 km) by testing the oxidation state of several diamonds from the Juína region using the ESRF.

The oxidation state of the Earth’s mantle controls important parameters and processes, such as magma generation, speciation and mobility of fluids and melts in the Earth’s interior, deep carbon cycle, recycling of oceanic crust back into the mantle, chemical differentiation of the planet and many others.

It is generally considered that the main three layers of the Earth – its crust, mantle and core, represent profound changes in the oxidation state of iron from ferric (Fe3+) at the surface to mostly Fe2+ in the silicate minerals in the upper mantle, transition zone and the lower mantle and ultimately, to the Fe0 in the core. In short, the surface is very oxidised and the core is metallic so it is very reduced.

Read more on the ESRF website

Image: Georgios Aprilis, ESRF postdoc at ID18 beamline