Metalโorganic frameworks with a Zr-oxo cluster [(Zr6O4(OH)4)]12โ are exceptionally stable and offer vast potential for a wide range of applications. Synthesis parameters strongly affect the quality, stability, morphology, etc., of the MOFs calling for elucidating of the various reaction steps.
Figure 1 top: Reaction kinetics of Zr-oxo-cluster formation in DMF based on LCF of the...
Extended X-ray Absorption Fine Structure (EXAFS) spectroscopy is a powerful technique for probing local atomic structure and thermal disorder. Its high sensitivity to atomic vibrations results in pronounced temperature-dependent damping of the EXAFS signal, making the technique a promising tool for non-contact thermometry, with applications ranging from nanoparticles [1] to materials under...
We present an integrated workflow for X-ray Absorption Spectroscopy (XAS) data processing, designed for extensible, automated analysis using Python. First, we developed a two-pass rolling median filter (with windows of 21 and 7 points and median absolute deviation thresholds of 6 and 5, respectively) to detect glitches from the incident intensity signal (Iโ). The identified glitches are then...
Abstract
X-ray Absorption Near-Edge Spectroscopy (XANES) is a key technique for studying the local structure of an atomic specie in matter. The technique provides information about the oxidation state, coordination number, and electronic configuration. Traditionally, XANES spectra are compared with those coming from model compounds, a process known as fingerprint analysis. However, for a...
Automated analysis during synchrotron experiments has become crucial for modern research facilities. Rapid feedback from precise analytical results allows scientists to adjust measurement conditions, choose appropriate samples, and deploy adaptive strategies effectively, leading to optimized experiments and faster scientific breakthroughs.
The near real-time analysis pipeline presented here...
Bismuth telluride (Bi$_2$Te$_3$), antimony telluride (Sb$_2$Te$_3$), and their solid solutions (Bi$_{2-x}$Sb$_x$Te$_3$) are among the most widely used thermoelectric (TE) materials owing to their excellent thermoelectric performance near room temperature.
Bi$_2$Te$_3$ and Sb$_2$Te$_3$ are isostructural compounds with complex two-dimensional layered structures consisting of...
Layered double hydroxides (LDH), with the typical formula [M1-x2+Mx3+(OH)2]x+[Ax/n]n-.mH2O, also known as anionic clays, are hydrotalcite-type positively charged lamellar material, in which a part of the divalent M2+ cations is substituted by trivalent M3+ cations. The electroneutrality of the material is ensured by the presence of anion located in the interlayer domain. The composition of the...
Introduction
While operando X-ray absorption spectroscopy (XAS) offers valuable insights into the dynamics of catalysts, it remains a bulk technique. This poses a challenge given that catalysis is a surface phenomenon. To address this limitation, a modulation excitation (ME) experimental design combined with phase-sensitive detection (PSD) analysis can be used. This approach...
Quantitative structural identification of active sites in heterogeneous catalysts under reaction conditions using bulk spectroscopic techniques remains fundamentally limited. This is particularly true for Fe-exchanged zeolites, which exhibit isolated Fe ions co-existing with oligomers, and larger aggregates. This poses several challenges: (i) distinguishing active sites from spectators, (ii)...
The data obtained from the synchrotron generally requires a considerable amount of time to be analyzed (months or years). As part of this project (funded by the PEPR DIADEM and started in February 2025), we aim to apply neural network algorithms in order to obtain a first estimate of the results directly from the raw data, in real time during the experiment.
In the first phase of the project,...
We present fully ab initio simulations of Fe L-edge X-ray absorption spectroscopy (XAS) for the archetype single-molecule magnet tetrairon Fe4 using a linear-response time-dependent density functional theory with a spin-orbital coupling scheme. In particular, electronic and structural modifications in the Fe4 core, as induced by Li doping and by the change of R (-H and...
Over the years, X-ray absorption spectroscopy is playing an increasingly important role in the development and innovations in battery science, due to its unique ability to provide accurate information on the electronic structure of redox active elements and local structural information, also in operando conditions. Despite its potential innovative outcomes, the generation of significant...
Resonant Inelastic X-ray Scattering (RIXS) is a powerful photon-in/photon-out spectroscopic technique that provides unique, orbital-specific insights into electronic structure by probing excitations from a localized core orbital. Its accurate simulation for condensed-phase systems requires a method that simultaneously describes the local electronic structure of the absorbing atom and the...
Transition metal nitrides (TMNs) are emerging as a promising class of materials for applications in optoelectronics, as well as energy conversion and storage; however, they remain relatively unexplored, primarily due to a lack of mechanistic understanding of their synthetic pathways. Here, a one-pot synthesis is demonstrated, yielding 3 nm phase-pure Cu3PdN nanoparticles after reacting Cu...
The extensive use of critical rare-earth elements like Nd and Sm in magnet production raises concerns about their limited availability [1]. Ongoing research explores the feasibility of cost-effective hard magnetic materials by substituting Nd or Sm with more abundant rare-earth elements such as Ce or La [2]. Here, it is crucial to deepen our understanding of the electronic and magnetic...
We present a Bayesian framework for robustly extracting spectroscopic features from X-ray Absorption Spectroscopy measurements and synthetic reference datasets. This approach is particularly designed for complex XAS experiments with noisy spectra and irregular backgrounds, especially under operando conditions in the soft X-ray regime, where absorption by membranes in the optical path, sample...
Density functional theory (DFT) based methods have become standard tools for accurately describing core-level spectroscopies in systems ranging from small gas-phase molecules to periodic condensed-phase materials. Within the Kohn-Sham DFT (KS-DFT) framework, core-excited states are commonly treated using linear-response time-dependent DFT (LR-TDDFT). More recently, real-time propagation...
Nuclear Resonance Vibrational Spectroscopy (NRVS) is a synchrotron-based inelastic X-ray scattering technique that probes the vibrational density of states projected onto a Mรถssbauer isotope. NRVS spectra can be transformed into an element-projected phonon density of states (PDOS) integrated over the Brillouin zone. While the forward problem - calculating the PDOS from a known structure and...
Platinum on high-surface-area carbon supports remains the benchmark oxygen-reduction-reaction (ORR) catalyst in proton-exchange-membrane fuel cells (PEMFCs) and a leading cathode for the hydrogen-evolution reaction (HER). The mesoporous N-doped carbon (MPNC) is used as a tunable platform to control dispersion and metal, support interactions, not as a field-wide state-of-the-art. The working...
At the MPI CEC, high energy resolution X-ray spectrometers are used for investigation molecular systems designed for storing and releasing energy in chemical bonds. X-ray absorption spectroscopy is, among the different spectroscopic techniques available at the institute, one option for interrogating the electronic and geometric structure of systems, permitting to investigate on an...
High-entropy oxides (HEOs) are multicomponent materials containing five or more cations distributed within a single crystalline lattice and are gaining attention as promising catalysts due to their unique structural stability, redox properties, and synergistic multi-cation effects [1]. Although HEOs are promising for a wide range of applications, their rational design remains challenging due...
CO2 hydrogenation to methanol offers a promising route for valorizing captured CO2 and contributes to the decarbonization of the chemical industry. A key challenge lies in designing active, selective, and stable catalysts. In2O3-based catalysts are highly active and selective for the hydrogenation of CO2 to methanol. However, unsupported In2O3 suffers from deactivation via overreduction to...
Identifying the true active species in homogeneous catalytic systems remains one of the most demanding challenges in modern spectroscopy. Low metal concentrations and dynamic reaction environments often make conventional EXAFS analysis impossible, leaving XANES as the only accessible technique for probing local structure.
In this work, we combine machine learning with fingerprint XANES...
