Conference Agenda

The energy transition requires the introduction of sustainable energy carriers to decarbonize global energy systems. Hydrogen is one of these options, but its efficient and sustainable production from water splitting as well as its storage is still a challenge. In our team, we are investigating various energy-related materials ranging from inorganic materials for hydrogen production and storage as well as electrode materials for batteries. To gain a comprehensive understanding of the structure–property relationships governing material performance, a multi-scale, multi-technique approach is employed that integrates in situ characterization methods with traditional ex situ analysis. This strategy enables to probe dynamic processes under real working conditions, capturing transient intermediates and structural evolution that are often missed in static measurements. Specifically, in situ total scattering techniques probe the local atomic arrangements in non-crystalline, amorphous, or highly disordered materials, providing insights at the sub-nanometre scale. Complementarily, high-resolution X-ray diffraction is used to characterize long-range ordered crystal structures. As one example, we present the nucleation and crystallisation pathways of transition metal oxides for photocatalytic water splitting. The evolution from amorphous precursor phases in solution through intermediate disordered phases to defined semiconductor nanostructures structures with tuneable bandgap properties will be discussed. In addition, electron microscopy and spectroscopic methods are essential to resolve atomic structures or defects. Furthermore, advanced tomographic techniques including X-ray computed tomography, provide critical insights into the complex three-dimensional architecture of electrode-electrolyte interfaces in battery systems, revealing morphological changes, interfacial reactions, and transport pathways that govern battery performance and longevity.

Geomaterials from diverse environments (e.g. from marine deposits, to active mines, and archaeological sites) present significant analytical challenges due to their structural complexity and heterogeneity. While standard X-ray diffraction (XRD) is routinely used for phase detection and quantification, it is difficult to scale to large sample sets due to rigorous preparation requirements to minimize artifacts like surface bias, preferred orientation, and long measurement times to achieve sensible phase detection limits.

This contribution presents the combination of a high-throughput experimental setup with high-energy synchrotron XRD and total scattering to overcome these limitations. High-energy X-rays penetrate deeply into the bulk, minimizing preparation artifacts, while high flux enables short measurement times and detection of trace minerals below 0.1 wt%. The same setup allows for complementary pair distribution function (PDF) analysis, an advanced technique critical for characterizing the amorphous and highly disordered phases not easily interpreted via standard crystallography, as well as small-angle scattering analysis for investigating microstructural details such as mesoporosity.

Historically, high-energy X-ray techniques were constrained by limited access and low sample throughput. The recent development of dedicated service resolves these bottlenecks, providing the broader geoscience community with reliable and rapid access to advanced and scalable structural analysis. This presentation details the advantages of high-energy radiation, target observables, and data analysis techniques. We will discuss how this scalable approach enables the systematic investigation of structure-property relationships across both crystalline and disordered phases.

Topotaxial intergrowth of amphibole in clinopyroxene in mantle rocks is of interest for the structural evolution from single to double-chain silicate minerals during magmatic and metasomatic processes involving fluid migration. Current high-resolution scanning transmission microscopy (STEM) can not only identify topotaxy between amphibole and diopside but also visualise nanometre-sized impurities at the interface. Here, we characterised the topotaxial interface in a natural sample of diopside from the subcontinental mantle peridotite body of Balmuccia (Ivrea-Verbano Zone, Italy) to clarify the formation mechanisms of the topotactic relationships and the talc-forming fluid migration process.

The High-angle annular dark-field (HAADF) STEM image of an interface between Amp and Di displays the existence of a talc-structured phase (Tlc) consisting of two tetrahedral cation sites (T) and one octahedral site (O) and forming a TOT layer in the vertical direction. The visibility of individual cation columns in the Z-contrast image reveals the modular structure of a polysomatic series of the minerals Amp, Tlc, and Di, consisting of pyroxene (Py) modules and mica (M) modules according to Thompson's "biopyriboles" criteria. In the HAADF image, the Amp structure is visible as the sequence …PyMPy… while Di and Tlc are indicated by the sequences …PyPyPy… and …MMM…, respectively. As illustrated in J.B. Thompson's drawing, the Amp structure can be visually divided into mica (M) and pyroxene (Py) modules along the vertical (010) boundaries in the experimental HAADF-STEM image. The discovery of Tlc at the interface between Di and Amp implies a selective fluid migration through the misfit dislocations.