X-Ray Absorption Spectroscopy - Science method

We study the electronic structure of Ta2NiSe5 in its low-temperature semiconducting phase, using resonant inelastic x-ray scattering (RIXS) at the Ta L3 edge. We also investigate the electronic properties of Ta2NiSe5 within the density-functional theory (DFT) using the generalized gradient approximation in the framework of the fully relativistic sp...

In this study, uniformly dispersed Pr³⁺ as an isolated atom over Ni/CeO2 catalyst (Ni‐Pr/CeO2) is designed to enhance catalytic activity for CO2 methanation, achieving an impressive 87% conversion with ≈100% CH4 selectivity at 300 °C temperature. In contrast, the traditional Ni/CeO2 and NiPr/CeO2‐imp catalysts exhibit poor conversion and selectivit...

Determining the particle chemical morphology is crucial for unraveling reactive uptake in atmospheric multiphase and heterogeneous chemistry. However, it remains challenging due to the complexity and inhomogeneity of aerosols particles. Using a scanning transmission X-ray microscopy (STXM) coupled with near-edge X-ray absorption fine structure (NEX...

The production of COx‐free hydrogen via the ammonia decomposition reaction (ADR) using Fe‐based non‐precious metal catalysts has attracted much attention. N─H bond cleavage and N─N coupling are two key steps in ADR, however, stronger Fe─N binding leads to lower activity of iron catalysts. Herein, we develop FeCu alloy catalysts with optimized metal...

To improve the performance of high‐energy‐density electrode materials for all‐solid‐state fluoride‐ion batteries (ASSFIBs), it is important to understand the structure and phase evolution during operation, which is closely correlated to capacity fading. In this study, an operando cell is designed compatible with laboratory X‐ray diffraction (XRD) t...

Precise regulation of electronic structure and nanoscale geometry represents a transformative strategy for breaking the activity‐stability trade‐off in oxygen evolution electrocatalysts. Here, highly exposed ultra‐small high‐entropy sulfides (HES, 5.2 nm) confined in porous carbon nanofibers are designed. This structure involves a dual‐engineering...

Copper‐containing enzymes catalyze the mono‐oxygenation of aromatic and aliphatic substrates in nature. Herein, we report on the synthesis of a new dinuclear copper complex supported by an octadentate ligand with a pyridazine backbone. Low‐temperature oxygenation leads to a μ‐1,1‐hydroperoxo dicopper(II) (Cu2OOH) complex, which in turn stoichiometr...

Calcium phosphate (CaP) is a family of materials closely resembling the mineral phase of natural bone and is widely used in bone tissue engineering for its biocompatibility and bioactivity. In this work, the starting material, Zn-doped calcium phosphate (Zn-CaP), was synthesized using the sol-gel method. Then, microfibers were fabricated using poly...

Electron-energy-loss spectroscopy (EELS) with an electron microscope and X-ray absorption spectroscopy (XAS) with a synchrotron are techniques for material characterization, both of which are based on exciting core electrons. Both techniques have a similar energy resolution, but while the spatial resolution of EELS can drop to atomic scales, the sp...

The single‐atom thickness of graphene holds great potential for device scaling, but its effectiveness as a thin metal‐ion diffusion barrier in microelectronics and a corrosion barrier for plasmonic devices is compromised by weak van der Waals interactions with copper (Cu), leading to delamination issues. In contrast, monolayer amorphous carbon (MAC...

The principal concern of this paper is to compare theoretical predictions for M5 → 5f x-ray absorption spectroscopy (XAS) obtained between an isolated linear NpO2²⁺ model and an embedded NpO2²⁺ model that takes into account the environment of the solution where XAS measurements are actually conducted. The embedded model is an NpO2[H2O]5²⁺ cluster....

Topologically protected spin states hold great promise for applications in next generation of memory circuits and spintronic devices. These intriguing textures typically emerge in bulk materials or heterostructures with broken inversion symmetry, accompanied by an enhanced Dzyaloshinskii‐Moriya interaction (DMI). In this study, the topological Hall...

Despite the growing significance of adsorbate-mediated strong metal-support interaction (A-SMSI) in various catalytic processes, a comprehensive mechanistic understanding of its formation and effective strategies for its precise modulation remain elusive. Herein, by constructing three well-defined model Ni/TiO 2 catalysts with distinct exposed face...

High‐valent Fe═O species, recognized as pivotal reactive oxygen intermediates in the catalyst‐activated peroxymonosulfate (PMS) oxidation system, play a dominant role in contaminant degradation. However, the inherent correlation between the Fe 3d electronic structure of heterogeneous catalysts and the generation efficiency of high‐valent Fe═O remai...

A thematic school, ASTER’X, is organized each year in Grenoble since 2021. This school focuses on training scientists using X-ray absorption techniques, X-ray emission spectroscopy, and X-ray imaging (tomography and ptychography), with lectures, tutorials and practicals. This handbook aims at gathering information needed during a XAS experiment, or...

Transition metal catalysts have promising applications as potential alternatives to platinum-based catalysts in oxygen reduction reactions (ORR), and fine-tuning their local electronic structure is an essential strategy to boost the intrinsic activity. Herein, a Zr–Cu heterojunction catalyst was synthesized by combining ZrO2/C and Cu2(OH)2CO3/C usi...

C(sp³)─O bonds are ubiquitous in natural and synthetic small molecules as well as polymers. The methodology for functionalizing C(sp³)─O bonds is of great importance for reforming these molecular structures into high‐value‐added chemical feedstocks. Here, we describe the reductive C(sp³)─O bond silylation of ethers with chlorosilanes and magnesium...

To enable the removal of persistent organic pollutants (POPs), the existing contamination concerns must be addressed with improved environmental sustainability. Given the encouraging results, Metal-Organic Frameworks (MOFs) have become viable options for radical solutions of removal POPs because of their remarkable and exceptional surface areas. Th...

Anion-exchange-membrane water electrolyzers (AEMWE) for hydrogen production have attracted interest because cost-effective Ni- and Fe-based catalysts can be used for the oxygen evolution reaction (OER). Although NiFe oxide/hydroxide-based catalysts have been extensively studied, the role of Fe and its chemical state during OER are not well understo...

Iron oxide and its composite adsorbents are widely used for removing arsenic and other potentially toxic elements (PTEs) due to their affordability and eco-friendly properties. However, understanding their selectivity and storage stability is vital for their effective use in practical applications. Current work reports the selectivity behavior of a...

While X-ray diffraction (XRD) is a commonly used method for quantification analysis using Rietveld refinement and quantitative Mössbauer spectroscopy is sporadically used primarily for iron speciation, laboratory X-ray Absorption Fine Structure Spectroscopy (lab-XAFS) is rarely applied for the quantitative determination of sample compositions. With...

Conducting real‐time, element‐specific studies of photo‐excited systems is a long‐standing challenge. The development of X‐ray free‐electron lasers (XFELs) has paved the way for the emergence of a promising technique: femtosecond X‐ray absorption spectroscopy (fs‐XAS). This powerful technique reveals electronic and geometric characteristics, provid...

Herein, the synthesis and characterization of Co0.66Fe0.34 layered double hydroxides (LDH) derived from pure and vacancy‐engineered V2CTx MXenes and their use as electrocatalysts for the oxygen evolution reaction (OER) is reported. Two distinct MXene materials are investigated: pristine V2CTx and V1.8CTx containing 10% vanadium vacancies. Through s...

Gas‐water/catalyst triple‐phase interface and the microenvironment play critical roles in the reaction kinetics and production rate of electrochemical carbon dioxide reduction reactions (CO2RR), which steer concerted proton‐electron transfer steps. Inspired by Tillandsia leaves, which efficiently capture H2O and CO2 from the air, copper nanosheets...

Background Soil organic matter (SOM) accumulation in forest soils is strongly influenced by interactions with inorganic constituents derived from parent material mineralogy. However, their role in the forest floor remains underexplored. Aims and methods This study investigates how different bedrock types (basalt, paragneiss, dolomite, limestone) i...

We report on the electronic properties of Cu based Delafossite material (CuCoO2) for the first time, using metal and oxygen K-edge and metal L3,2-edge x-ray absorption spectroscopy (XAS). The structural and morphological characterization are carried out using x-ray diffraction, Fourier transfer infrared spectroscopy (FTIR) and electron microscopy....

Phase transitions in transition metal oxides, particularly those involving charge, orbital, and spin order, give rise to emergent electronic and magnetic phenomena, making these materials critical to the advancement of spintronics and quantum technologies. SrRuO3 (SRO) and LaNiO3 (LNO) have distinct physical properties. SRO is characterized by its...

The Suzuki–Miyaura coupling (SMC) reaction is an efficient method for constructing C(aryl)–C(aryl) bonds. SMC reactions are typically carried out in the presence of base additives (>100 mol%), thereby leading to increased by‐product formation. In this study, the promotional effect of an O2 atmosphere on the SMC reaction was demonstrated without the...

Cu-Cu 2 O-rGO composite layers were electrodeposited for the first time from alkaline copper(II) lactate-based electrolytes containing dispersed rGO flakes. The properties of electrodeposited composite materials are strongly affected by applied potentials. Obtained layers were investigated towards their catalytic activity in electro-and photoelectr...

High-entropy oxides (HEOs) are a promising class of multicomponent ceramics with tunable structural and electronic properties. In this study, we investigate the local electronic structure of rare-earth HEOs in the (Ce, Sm, Pr, La, Y)O2 system using X-ray absorption spectroscopy (XAS). By systematically increasing the Ce concentration, we observe a...

Dopant positioning within metal oxide lattices has a significant influence on catalytic performance, yet it remains underexplored in many transition metal-doped systems. Using density functional theory (DFT) calculations, this study demonstrates that cobalt (Co) and manganese (Mn) dopants preferentially integrate into the bulk of the ZnO lattice, t...

Perfluorinated compounds (PFCs), such as PFOS and PFOA, are persistent organic pollutants that pose significant environmental and health risks due to their chemical stability and bioaccumulative nature. Metal-organic frameworks (MOFs), with their highly tunable porosity and chemical functionality, have emerged as promising adsorbents for the captur...

Understanding the factors that control the speciation of metal ions in molten salts is crucial for the successful deployment of molten salts in both concentrated solar power and nuclear energy applications. The speciation of the Ni(ii) ion is of interest because it is a common corrosion product, and the distribution of coordination states it occupi...

Time-resolved absorption spectroscopy and magnetic circular dichroism with circularly polarized soft x-rays (XAS and XMCD) are powerful tools to probe electronic and magnetic dynamics in magnetic materials element- and site-selectively. By employing these methods, groundbreaking results have been obtained, for instance, for magnetic alloys, which h...

The selective hydrogenation of unsaturated hydrocarbons is essential for the production of alkenes used in polymerization processes. Au‐based catalysts offer greater selectivity than Pd but are limited by poor hydrogen activation. Alloying Au with Cu offers a promising approach to enhance catalytic performance by improving activity while retaining...

The integration of transition metal‐carbon composites has shown remarkable potential in achieving superior bifunctional electrocatalytic activity and robust stability in rechargeable zinc‐air batteries (ZABs), primarily through electronic structure modulation and strategic structural design. While significant research is dedicated to the initial st...

The spin‐crossover (SCO) properties of the dinuclear complex [{Fe(H2B(pz)2)2}2μ−(ac(bipy)2)]$\left[\right. \left{\right. \text{Fe} \left(\left(\right. \left(\text{H}\right)_{2} \text{B} \left(\left(\right. \text{pz} \left.\right)\right)_{2} \left.\right)\right)_{2} \left(\left.\right}\right)_{2} \mu - \left(\right. \left(\text{ac(bipy)}\right)_{2}...

Extensive research has been conducted on carbon‐supported single‐atom catalysts (SACs) for electrochemical applications, owing to their outstanding conductivity and high metal atom utilization. The atomic dispersion of active sites provides an ideal platform to investigate the structure–performance correlations. Despite this, the development of str...

Nickel‐based perovskite oxides are identified as promising candidates for oxygen evolution reaction (OER) catalysts in view of their low cost, highly tunable structure, and potential high activity. However, the performance and catalyst design are hindered by their sluggish surface reconstruction kinetics. We introduce a ferric ion pre‐etching strat...

Oxide glasses and melts are of interest in many fields of science and technology. The structural and physico-chemical properties of C12A7, C11M1A7, C10M2A7, C9M3A7, and C8M4A7 glasses (C = CaO, M = MgO and A = Al2O3) were studied for the first time. It was shown by Al K-edge XANES spectroscopy that Al is in fourfold coordination in all studied glas...

High‐valent iron active species (HVIAS)‐driven peroxymonosulfate (PMS) activation has emerged as a transformative approach in environmental remediation. This review systematically deciphers the mechanistic evolution and characterization advances of HVIAS generation: non‐radical‐dominated electron transfer pathways have been rigorously elucidated th...

Under the DAPHNE4NFDI consortium, RefXAS has evolved as a comprehensive open-access database for X-ray absorption spectroscopy (XAS). We have implemented a platform that allows users to submit raw datasets and associated metadata via a web interface. The database supports automated metadata handling and quality control, ensuring that uploaded data...

Current plans for managing high-level nuclear waste may involve sequestration in borosilicate glass and potential disposal in geological repositories. However, there is considerable interest in using ceramic oxides, such as pyrochlores, as alternative nuclear waste forms due to the high chemical durability and waste loading capabilities of these ma...

This contribution will report on a detection system specially designed and developed to fulfil the needs of X-ray Absorption Spectroscopy (XAS) experiments at the XAFS beamline of the ELETTRA synchrotron. It is composed of 8 monolithic multipixel arrays of Silicon Drift Detectors (SDDs), each comprising 8 cells (3x3 mm ² ) fabricated on 450- µ m-th...

Structural dynamics in electrocatalysts under operating conditions, including restructuring, dissolution/redeposition, and single-site-to-cluster transitions, are commonly observed phenomena but are often poorly understood. Cu-based catalysts, entailing single-atom catalysts (SACs), molecular catalysts, and nanostructured catalysts, have shown prom...

FDA (Fast Data Analyzer) is a versatile software tool designed for the analysis of X-ray absorption spectra (XAS) and X-ray diffraction patterns (XRD), collected during in situ/operando experiments at the NOTOS and CLAESS beamlines of ALBA synchrotron. The program is coded in Python 3 and Qt5 and aims to provide an easy online tool for data reducti...

Dry reforming of methane (DRM) offers a sustainable route to convert CH4 and CO2 into syngas, addressing both greenhouse gas emissions and energy demand. However, catalyst deactivation due to sintering and coking limits practical applications. In this work, we developed a mesoporous Ni-based catalyst (Ni/ZrSBA-15-OH) featuring abundant Ni-ZrO2 inte...

Advancements in synchrotron and X-ray free-electron sources and associated developments in instrumentation and techniques offer many new possibilities for researchers. At the same time there is increasing demand and pressure to implement the FAIR data principles by which data should be made Findable, Accessible, Interoperable and Reusable. The cons...

Five large‐scale treatment wetlands, the Everglades Stormwater Treatment Areas (STAs), have been constructed in south Florida to reduce phosphorus (P) transport into the Florida Everglades. While the STAs have successfully reduced P entering downstream waterbodies by at least 77%, concentrations in outflow waters still exceed target values in many...

Yttrium ruthenate pyrochlores have become popular as electrocatalysts for the oxygen evolution reaction in water electrolysis. However, the traditional synthesis routes used to prepare these Y2Ru2−xYxO7 electrocatalysts require calcination at temperatures higher than 1000 °C for extended periods of time, resulting in highly sintered particles. We p...

Titanium oxynitride (TiNO) thin films represent a multifaceted material system applicable in diverse fields, including energy storage, solar cells, sensors, protective coatings, and electrocatalysis. This study reports the synthesis of TiNO thin films grown at different substrate temperatures using pulsed laser deposition. A comprehensive structura...

We show that ultrafast electronic $4f$ multiplet transitions in terbium metal are manifested by changes in the relative spectral weight of the $M_5$ and $M_4$ X-ray absorption resonances. Our experimental results are supported by a simulation of excited multiplet spectra with atomistic calculations; they prove that the so-called third rule of Thole...

On‐site hydrogen gas production from hydrogen‐rich liquids offers a clean alternative to fossil fuels for combustion that is readily implemented in existing energy infrastructure. A heterogenized (POCOP)‐Ir pincer catalyst can be operated at higher temperatures for higher turnover frequency, but the reaction pathway of the reported complex has not...

Sulphur is present in a vast multitude of biological compounds, and X-ray absorption spectroscopy (XAS) is a powerful and well-established characterization technique to study the local atomic environment of this chemical element in such systems in detail, with a high potential for advancing knowledge in medicine, biotechnology and environmental res...

The complexity of actinide chemistry and physics, driven by intricate electronic structures, variable oxidation states, and radioactive properties, poses significant challenges for scientific exploration. Synchrotron radiation methods, including X‐ray Absorption Spectroscopy (XAS), X‐ray Emission Spectroscopy (XES), high energy resolution fluoresce...

Industrial activity in the Besòs River watershed has historically contributed to significant heavy metal pollution in coastal sediments near Barcelona. While mitigation measures implemented since the 1980s have effectively reduced contamination in surface sediments, deeper layers remain polluted. Increasing societal and economic pressures, along wi...

X-ray absorption near edge structure (XANES) spectroscopy is a powerful technique for characterizing the chemical state and symmetry of individual elements within materials, but requires collecting data at many energy points which can be time-consuming. While adaptive sampling methods exist for efficiently collecting spectroscopic data, they often...

Time-resolved structural changes taking place during the reaction of Ca(OH)2 and CO2 forming different CaCO3 polymorphs, in aqueous and non-aqueous environments, were recorded operando using mid-infrared (mid-IR) and X-ray absorption near-edge structure (XANES) spectroscopy. Results show that Ca(OH)2 directly transforms into calcite in a pure water...

Cathode materials Li 1 − x Ni 1 − z Co z / 2 Mn z / 2 O 2 with z = 1 / 5 (NCM811), z = 2 / 5 (NCM622), or z = 2 / 3 (NCM111) in (i) the pristine state, (ii) charged to x = 0.5 or x = 0.65 , and (iii) discharged after having been charged previously were characterized by x-ray diffraction (XRD), x-ray absorption spectroscopy (XAS), direct current (DC...

The multi-state n-electron valence second-order perturbation theory with core–valance separation (CVS) approximation (CVS-MS-NEVPT2) and static-dynamic-static multi-state multi-reference second-order perturbation theory with CVS (CVS-SDSPT2) were developed based on the internally contracted multi-reference configuration interaction method with sing...

Topologically protected spin states hold great promise for applications in next generation of memory circuits and spintronic devices. These intriguing textures typically emerge in bulk materials or heterostructures with broken inversion symmetry, accompanied by an enhanced Dzyaloshinskii-Moriya interaction (DMI). In this study, we successfully indu...

Submarine hydrothermal vents harbor diverse microbial communities and have long intrigued researchers studying the origin of life. Transition metals in these environments can be reduced by serpentinization, potentially forming zeolite‐supported transition metal nanoparticles capable of driving prebiotic chemistry. This inorganic structure could cat...

Manifestations of electron scattering in X-ray spectroscopy have been evident for decades. Here, it will be shown that the proper interpretation of variants of X-ray Absorption Spectroscopy (XAS) of actinide materials must include an accurate treatment of features caused by electron scattering, i.e., EXAFS or Extended X-ray Absorption Fine Structur...

We have studied the electronic and magnetic properties of the A- and B-site-ordered perovskite CaCu3Re2Fe2O12 within the density-functional theory using the generalized gradient approximation (GGA) with the consideration of strong Coulomb correlations (GGA+U ) in the framework of the fully relativistic spin-polarized Dirac linear muffin-tin orbital...

The rising demand for sustainable green hydrogen production necessitates efficient and cost‐effective water‐splitting electrocatalysts. Inspired by the catalytic activities of columbite‐tantalite, this study combines a scalable cutting‐edge synthesis approach with atomic‐level structures and metal‐center‐mediated mechanisms to unravel its operation...

Solid oxide cells (SOCs) are a promising technology that can both utilize fuel efficiently in fuel cell mode (SOFC) and store energy as fuel in electrolysis mode (SOEC). Of particular interest is the ability to use clean and renewable energy to both electrolyze water to make hydrogen fuel, and convert CO2 produced during combustion into valuable pr...

Ce2Pt6Ga15 is a heavy fermion compound near the quantum critical point (QCP). Its crystal structure may exhibit magnetic frustration due to a honeycomb arrangement; however, stacking faults in the crystal hinder structural analysis. As a local structure probe, extended X-ray absorption fine structure (EXAFS) is less sensitive to stacking faults and...

Pseudomonas aeruginosa is a ubiquitous, Gram-negative bacterium that forms biofilms and is responsible for antibiotic-resistant nosocomial infections in humans. The P. aeruginosa BqsRS two-component system (TCS) regulates biofilm formation and dispersal by sensing extracytoplasmic Fe ²⁺ , but the mechanistic details of this process are poorly under...

Single-particle methods based on Kohn-Sham unoccupied states to describe near-edge X-ray absorption (XAS) spectra are routinely applied for the description of K-edge spectra, as there is no complication due to spin-orbit (SO) coupling. L- and M-edge spectra are often addressed via variants of time-dependent density functional theory (TDDFT) based o...

A fundamental step toward studying the unique properties of actinide nanomaterials is control over the shape of actinide nanoparticles. Toward this goal, this work demonstrates the effects of precursor identity and surfactant concentration on the shape of uranium dioxide (UO2) nanoparticles. UO2 nanoparticles were synthesized by thermal decompositi...

Pseudomonas aeruginosa (P. aeruginosa), a ubiquitous Gram-negative bacterium best known for infecting the lungs of cystic fibrosis (CF) patients, is one of the major causes of chronic nosocomial infections and can grow either as planktonic or biofilm. Biofilms are complex microbial structures capable of providing an advantageous protective quality...

The ground‐state electronic/geometrical structures of the three C27B fullerene isomers and the corresponding parental carbon cage Td‐#2C28, as well as the respective embedded derivatives U@C27B have been calculated at the density functional theory level. The three isomers of C27B are identified by theoretical simulations of X‐ray photoelectron spec...

This study highlights the efficiency of Cu‐FER catalysts with varying copper loadings in transforming carbon dioxide (CO2) and methane (CH4) into methanol or acetic acid. The XAS, UV–vis, and FTIR analyses confirmed that Cu‐FER catalysts with low copper loading contain a high fraction of isolated Cu²⁺ cations, while those with high copper loading e...

Ceria nanoparticles supported on alumina are widely used in various catalytic reactions, particularly in conjunction with platinum group metals (PGMs)1, 2, 3, 4, 5, 6, 7, 8–9. Here we found that treating these catalysts at temperatures between 750 and about 1,000 °C in the presence of CO and NO in steam (reactive treatment under reducing atmosphere...