Critical raw materials from electrolysers back into the cycle

Researchers succeed in recycling functional materials for hydrogen production

Hydrogen plays a central role in the energy transition. The gas is mainly produced with the help of electrolysers. This process requires critical raw materials such as platinum group metals, rare earths or nickel as catalysts. Researchers at the Helmholtz Institute Freiberg for Resource Technology (HIF), an institute of the Helmholtz-Zentrum Dresden-Rossendorf (HZDR), have now been able to recover these functional materials using innovative flotation processes and liquid-liquid particle separation, thus returning them to the material cycle. The research is part of the H2Giga lead project of the German Federal Ministry of Education and Research (BMBF), which is investigating the longevity and recyclability of hydrogen electrolysers.

Hydrogen is considered a clean energy source that can help reduce CO2 emissions. The focus here is particularly on green hydrogen, which is produced through the electrolysis of water using renewable energies such as wind and solar power. Hydrogen is used in industry, for example as a raw material for the production of chemicals and steel, as well as in the transport sector, where it is used as a fuel for fuel cell vehicles. Hydrogen can also be used to store surplus energy from renewable sources, making it an important building block for a sustainable and climate-friendly energy future. According to the national hydrogen strategy, Germany is expected to need 95 to 135 terawatt hours of hydrogen in 2030.

Various processes can be used to produce hydrogen – one is water electrolysis: water is broken down into hydrogen and oxygen using an electric current. The catalysts in the electrolyser consist of critical metals, the so-called functional materials. Proton exchange membrane electrolysers (PEM) mainly use metals from the platinum group, such as platinum, iridium and palladium. High-temperature electrolysers use rare earths and nickel. These critical raw materials need to be secured. This is a project that HIF researchers are working on under the leadership of the TU Bergakademie Freiberg in the ReNaRe project.

ReNaRe stands for Recycling – Sustainable Resource Utilization and is part of the H2Giga flagship project. To implement the national hydrogen strategy, the BMBF has set up three flagship projects for Germany’s entry into the hydrogen economy. One of these is H2Giga, which focuses on the series production of hydrogen electrolysers. ReNaRe concentrates on the end of life of electrolysers in order to return the materials used, and in particular the critical metals, to the material cycle.

“We are involved in the recycling of PEM and high-temperature electrolysers, as they are easy to dismantle. We use ultra-fine particle separation techniques to recover the functional materials. This is because the critical anode and cathode materials are present as fine particles. Their size corresponds to approximately one hundredth of a human hair. Liquid-liquid particle separation and agglomeration flotation have proven to be suitable for separating the functional materials. The extraction of ultrafine particles uses a sustainable solvent-water circulation system for the effective separation of hydrophobic, i.e. water-repellent cathode catalysts and hydrophilic (water-attracting) anode catalysts. The complementary agglomeration flotation uses an innovative, sustainable hydrophobic binder to enable agglomeration of the particles into a uniform mass. The binder is based on a special emulsion technology, i.e. an oil-water mixture with a very high water content, which selectively agglomerates hydrophobic ultrafine particles. This enables the separation of hydrophilic ultrafine particles by adhesion to gas bubbles and discharge in the foam,” says Sohyun Ahn, PhD student at the HIF, describing the procedure. “With both processes, we were able to recover up to 90 percent of the critical functional materials and return them to the material cycle. An important step towards operating hydrogen electrolysis economically and sustainably.”

Read more on HZDR website

Image: Water drop (black) above a hydrophobic particle (grey are at the bottom)

Source: Ahn, Sohyun

Lake source cooling brings sustainability, precision to synchrotron

The science of flinging around X-rays, electrons and positron beams to study the secret life of matter requires a tremendous amount of energy. It also requires a constant supply of cool water to keep the technology functioning consistently and prevent it from overheating.

For decades, the Wilson Laboratory, which houses the Cornell High Energy Synchrotron Source (CHESS), has relied on four immense cooling towers that evaporate 10,000 gallons of water daily to reduce the temperature of the nearly 650 electromagnets – some roughly twice the size of a human being – that line a half-mile-long ring buried 40 feet below a scenic swath of east campus.

Those towers are now obsolete because the lab has tapped into the university’s Lake Source Cooling (LSC) system, which draws cold water from the depths of Cayuga Lake to remove heat from the district chilled water loop that cools the majority of Cornell facilities. For Wilson Lab, this approach is not only more efficient and sustainable – it will bring greater precision to its experiments. LSC will also, for the first time, enable CHESS to operate year-round.

Read more on the CHESS website

Image: Leila Aboharb, mechanical systems engineer at Wilson Lab, says Lake Source Cooling is a much more reliable system than the four cooling towers that were installed in 1989.

Credit: Noël Heaney/Cornell University

Tetra Pak commences first-of-its-kind sustainability research

The newest research station at MAX IV, ForMAX, has hosted its first industry experiment: A ground-breaking study on fibre-based sustainable food packaging, performed by Tetra Pak in collaboration with Chalmers University of Technology.

Today, global food packaging and processing company Tetra Pak announces the commencement of new research using advanced X-ray scattering imaging techniques at ForMAX, the newest beamline at MAX IV laboratory. The study aims to uncover fresh insights into the nanostructure of fibre materials, with the first application to optimise the composition of materials used for paper straws.

In the strive to meet the increased global market demand for more sustainable packaging solutions, new materials based on paper can bring novel opportunities. Yet, these new, paper-based materials must remain food safe, recyclable, and durable against liquids and humidity while meeting the increased sustainability demands.

These are some of the challenges that Tetra Pak is collaborating with MAX IV to address using the laboratory’s advanced research techniques.

“Our first experiment, which starts with paper straws, provides additional analysis capabilities into how paper straw material responds to changes in the environment in real-time, as well as how the straw interacts with different types of liquids under stringent conditions. These new insights and knowledge will be applied to developing the paper straws of the future in our virtual modelling tools, helping us to improve their functionality”, explains Eskil Andreasson, Technology Specialist, Virtual Modelling at Tetra Pak.

Read more on the MAX IV website

Image: Eskil Andreasson (middle), Technology Specialist at Tetra Pak, with the research team listening to Linnéa Björn in the ForMAX control room at MAX IV.

Credit: Anna Sandahl, MAX IV

ForMAX beamline is now open for experiments

ForMAX, the newest beamline at MAX IV, is now officially open for experiments. The focus will be research on new, sustainable materials from the forest, but the beamline will also be useful for research in many other fields and industries, including food, textiles, and life science.

ForMAX is specially designed for advanced studies on wood-based materials. It allows in-situ multiscale structural characterization from nm to mm length scales by combining full-field tomographic imaging, small- and wide-angle X-ray scattering (SWAXS), and scanning SWAXS imaging – in a single instrument.

The beamline is an initiative where several market-leading industry companies, mainly from the paper and pulp industry, and academia have joined forces. The construction work has been funded by the Knut and Alice Wallenberg Foundation, and the operational costs are funded by the industry through Treesearch, a national collaborative platform for academic and industrial research in new materials from the forest.

One goal with ForMAX is to facilitate the development of new, wood-based products that can replace today’s plastic products.

Read more on the MAX IV website

Image: ForMAX beamline

Credit: Anna Sandahl, MAX IV

European Young Chemists’ Award for Sebastian Weber

In recognition of Sebastian’s PhD thesis on hard X-ray microscopy, tomography, and application of synchrotron radiation in catalysis research

Sebastian Weber, a recent PhD graduate at the Institute for Chemical Technology and Polymer Chemistry (ITCP) / Institute for Catalysis Research and Technology (IKFT) at Karlsruhe Institute of Technology (KIT), was awarded the Gold Medal in the PhD category of the European Young Chemists‘ Award. The award is presented every two years during the EuChemS Chemistry Congress on behalf of the Società Chimica Italiana (SCI) and the European Chemical Society (EuChemS). The prize highlights excellent research from young / early stage researchers across all fields of chemistry and chemical sciences. During his PhD phase, Sebastian Weber studied materials used in heterogeneous catalysis with a broad range of spatially-resolved X-ray characterisation methods, in order to gain a deeper understanding of the structure and function of catalysts. The project made extensive use of synchrotron radiation, specifically X-ray microscopy and tomography as emerging methods in catalysis research. This success on the European level highlights the leading role which synchrotron science has to play in the study of matter.

Catalysis plays a crucial role in sustainable chemical production, chemical energy conversion and storage, among many others, and is a key technology area in synchrotron radiation research. During his PhD work at Karlsruhe Institute of Technology, Sebastian Weber studied catalysts for CO2 methanation using spatially-resolved characterisation tools including X-ray microscopy and tomography. These diverse X-ray imaging methods were exploited to study the 3D structure of catalytic materials over a range of length scales, addressing various levels of hierarchical structural features which are critical to understanding catalyst performance. This topic is a special focus of the Young Investigator Group of Dr. Thomas Sheppard at KIT, who supervised and secured funding for the project, within the wider group of Prof. Jan-Dierk Grunwaldt.

Only a handful of research groups worldwide are currently active in the field of X-ray microscopy applied to catalysis research, highlighting the emerging role of this vibrant research field. During his PhD work, Sebastian Weber in particular worked to develop applications of hard X-ray ptychography and ptychographic X-ray tomography (PXCT) to study catalyst pore structures, structural evolution under reaction conditions, and the effects of catalyst deactivation. These methods routinely reach spatial resolution below 50 nanometres (0.001 x diameter of a human hair), and have been applied so far on samples up to 50 micron in diameter (ca. the diameter of a human hair). The further development of ptychography holds excellent potential for catalysis and materials research, particularly in the age of fourth generation light sources with improved coherence and decreased source emittance. The project resulted in several high quality publications in leading chemistry and materials journals, reflecting the knowledge gained regarding 3D structure of catalysts, and the potential for development of improved catalysts in future.

Sebastian Weber recently completed his doctorate with the title “Revealing Porosity and Structure of Ni-based Catalysts for Dynamic CO2 Methanation with Hard X-rays”, earning a distinction from KIT. Now his work was further recognised by securing the Gold Medal of the European Young Chemists’ Award at PhD level. The award is presented every two years during the EuChemS Chemistry Congress on behalf of the Società Chimica Italiana (SCI) and the European Chemical Society (EuChemS). The prize highlights excellent research from young / early stage researchers across all fields of chemistry and chemical sciences, and is therefore a highly competitive prize. After a pre-selection phase based on scientific excellence, the six finalists each held a presentation at the EuChemS Chemistry Congress in Lisbon, Portugal. The award not only highlights the excellent contribution of Sebastian Weber to the field of chemical sciences, but promotes in front a broad audience the essential role of synchrotron radiation in delivering future insights and innovations across the field of natural sciences.

Related articles on this research can be found in the Diamond Annual Review 2021-2022, “X-ray ptychography investigates coking of solid catalysts in 3D”, p.66-67, and on the DESY website

Image: Award ceremony during the 8th EuChemS Chemistry Congress in Lisbon, Portugal, Sebastian Weber (KIT, left), Prof. Floris Rutjes (President of the European Chemical Society, middle) and Prof. Angela Agostiano (Chair of the EYCA Award Committee, right).

Graphics: EYCA

Ultra-white beetle scales may be the key to more sustainable paint

An international team of researchers has managed to mimic the colour of the Cyphochilus beetle scales – one of the brightest whites in nature, thanks to the ESRF’s imaging capabilities. This could help the development of ultra-white, sustainable paints.

Cyphochilus beetle scales are one of the brightest whites in nature. Until now, researchers did not known how their ultra-white appearance is created. X-ray nanotomography experiments at the ESRF have shown that the nanostructure in their tiny scales creates the colour, not the use of pigment or dyes.
Andrew Parnell, from the University of Sheffield and corresponding author of the study said: “In the natural world, whiteness is usually created by a foamy Swiss cheese-like structure made of a solid interconnected network and air. Until now, how these structures form and develop and how they have evolved light-scattering properties has remained a mystery.”
The findings show that the foamy structure of the beetles’ scales has the right proportion of empty spaces, in a highly interconnected nano-network, which optimise the scattering of light – creating the ultra-white colouring.

>Read more on the European Synchrotron website

Image: Andrew Denison and Stephanie Burg in the experimental hutch of beamline ID16B.