MYSTIIC at BESSY II: New X-ray microscope put into operation
The first image taken by MYSTIIC: a standard image used to calibrate and measure the resolution of the new STXM. © HZB
The pictures below illustrate the capabilities of correlative in situ microscopy, using the example of (Mo,V,Te,Nb)Ox - a catalyst. This figure shows NEXAFS-TXM at U41 in different gas atmospheres, the data show changes in the electronic states of the elements involved. © C.Pratsch/HZB ; T. Lunkenbein/FHI
Correlative microscopy images of the same sample site within the transmission electron microscope (TEM). © K. Dembélé/FHI
The same sample under a full-field transmission X-ray microscope TXM at the U41 beamline at BESSY II, HZB) in a gas atmosphere. © C. Pratsch/HZB
A new X-ray microscope has started operation at the Energy Materials in situ Lab (EMIL). It is a scanning transmission X-ray microscope designed to examine both sample surfaces and bulk sample. With the soft X-ray light from BESSY II, it is even possible to localise individual elements and chemical compounds; the spatial resolution is below 20 nanometres.
The Energy Materials in situ Lab (EMIL) is directly connected to two beamlines at BESSY II, which provide intense synchrotron radiation for research. One beamline provides hard X-rays, the other soft X-rays for the experiments at EMIL. EMIL is operated jointly by HZB and the Max Planck Society (MPG) . Now, an HZB team has set up a new scanning transmission X-ray microscope (STXM) at the soft X-ray beamline in the BESSY II experimental hall. It was named MYSTIIC - Microscope for x-raY Scanning Transmission In-situ Imaging of Catalysts.
Higher precision and more options
Compared to other X-ray microscopes, the STXM MYSTIIC at EMIL offers even higher precision and more options for scanning surfaces and investigating bulk samples in transmission. In particular, MYSTIIC will also allow to observe chemical processes in gas/liquid cells in the future. "It is like filming the processes taking place during catalysis," says HZB expert Dr Markus Weigand, who is in charge of the instrument. The implementation of a gas mixing system, which is being developed together with the AC department of the Fritz Haber Institute (FHI) of the Max Planck Society, is currently in progress in order to analyse how different gases (for example CO2, CH4, H2 etc.) chemically change the surface of a catalyst on the nanoscale. The new microscope will thus contribute significantly to CatLab's approach on knowledge and understanding in order to develop novel catalyst.
Testing the instrument with friendly users
"Initially, we want to test the instrument with HZB teams or users we know (friendly users)," explains Weigand. For example, HZB researcher Dr Tristan Petit will be the first to investigate so-called MXenes with MYSTIIC. MXenes can absorb and store large amounts of electrical energy very fast. "We want to scan the surfaces of MXene particles with MYSTIIC and find out which elements are involved in certain chemical processes. This will help us to better understand the amazing properties of this class of materials," Petit explains. He and his team are currently preparing the installation of special sample cells for investigations on catalysis, electrochemistry and electrocatalysis. Sample heating up to 1000 °C is also planned. In the future, routines will be developed in collaboration with the FHI that will make it possible to use the same cells for electron microscopy studies in order to combine energy and spatial resolution on the same sample.
Upgrades in mind
The instrument is designed with upgrades to expand capabilities in mind, which will include advanced operando cells and x-ray cameras systems to enable resolving structures of even a few nanometres using ptychographic methods.
MYSTIIC: Energy materials and environmental sciences
Up to now, there have been two X-ray microscopes at BESSY II with very different purposes. Another STXM (MAXYMUS), operated by MPI-IS, focuses on magnetism and time resolution. Nanoscale NEXAFS* spectromicroscopy of energy materials (see examples below) and tomography – for example of shock frozen cells - in the soft and tender X-ray regime can be examined in Prof. Dr. Gerd Schneider's group. MYSTIIC at EMIL is particularly suitable for resolving questions related to energy materials research and environmental sciences.
External users are invited to apply for beam time at MYSTIIC at EMIL from the first call for 2022.
*NEXAFS: Near Edge X-ray Absorption Fine Structure.
- Battery research with the HZB X-ray microscopeNew cathode materials are being developed to further increase the capacity of lithium batteries. Multilayer lithium-rich transition metal oxides (LRTMOs) offer particularly high energy density. However, their capacity decreases with each charging cycle due to structural and chemical changes. Using X-ray methods at BESSY II, teams from several Chinese research institutions have now investigated these changes for the first time with highest precision: at the unique X-ray microscope, they were able to observe morphological and structural developments on the nanometre scale and also clarify chemical changes.
- BESSY II: New procedure for better thermoplasticsBio-based thermoplastics are produced from renewable organic materials and can be recycled after use. Their resilience can be improved by blending bio-based thermoplastics with other thermoplastics. However, the interface between the materials in these blends sometimes requires enhancement to achieve optimal properties. A team from the Eindhoven University of Technology in the Netherlands has now investigated at BESSY II how a new process enables thermoplastic blends with a high interfacial strength to be made from two base materials: Images taken at the new nano station of the IRIS beamline showed that nanocrystalline layers form during the process, which increase material performance.
- Hydrogen: Breakthrough in alkaline membrane electrolysersA team from the Technical University of Berlin, HZB, IMTEK (University of Freiburg) and Siemens Energy has developed a highly efficient alkaline membrane electrolyser that approaches the performance of established PEM electrolysers. What makes this achievement remarkable is the use of inexpensive nickel compounds for the anode catalyst, replacing costly and rare iridium. At BESSY II, the team was able to elucidate the catalytic processes in detail using operando measurements, and a theory team (USA, Singapore) provided a consistent molecular description. In Freiburg, prototype cells were built using a new coating process and tested in operation. The results have been published in the prestigious journal Nature Catalysis.