Publications associées à Spectrométrie d'absorption des rayons X

Competition between Carrier Injection and Structural Distortions in Electron-Doped Perovskite Nickelate Thin Films

Duncan Thomas Lindsay Alexander, Bernat Mundet, Jonathan Spring, Jean-Marc Triscone

The discovery of superconductivity in doped infinite-layer nickelate thin films has brought increased attention to the behavior of the doped perovskite phase. Despite this interest, the majority of existing studies pertain to hole-doped perovskite rare-ear ...

WILEY2023

Graphene nanoplatelets promoted CoO-based catalyst for low temperature CO2 methanation reaction

Andreas Züttel, Thi Ha My Pham, Youngdon Ko, Liping Zhong

Methanation of CO2 is an important reaction for reducing CO2 emissions in a power-to-gas system. Compared to cobalt supported on gamma-Al2O3, cobalt supported on graphene nanoplatelets (GNPs) showed significantly better performance for CO2 methanation. Cob ...

FRONTIERS MEDIA SA2023

Jahn-Teller effects in initial and final states: high-resolution X-ray absorption, photoelectron and Auger spectroscopy of allene

Majed Chergui, Camila Bacellar Cases Da Silveira, Luca Longetti, Rebecca Ann Ingle, Ludmila Maria Diniz Leroy, Thomas Roland Barillot, Daniel Hollas

Carbon K-edge resonant Auger spectra of gas-phase allene following excitation of the pre-edge 1s -> pi* transitions are presented and analysed with the support of EOM-CCSD/cc-pVTZ calculations. X-Ray absorption (XAS), X-ray photoelectron (XPS), valence ban ...

ROYAL SOC CHEMISTRY2023

Understanding the role of surface oxygen-containing functional groups on carbon-supported cobalt catalysts for the oxygen evolution reaction

Andreas Züttel, Thi Ha My Pham, Kangning Zhao, Youngdon Ko, Liping Zhong, Manhui Wei

Supported Co-based catalysts exhibit promising catalytic activities in the oxygen evolution reaction (OER) during alkaline water electrolysis. Surface functionalization of the support modulates the dispersion of the catalysts and their interaction with the ...

Royal Society of Chemistry2023

Investigations on Caesium Dispersion and Molybdenum Coating on SPIDER Components

Michele Fadone

SPIDER is the 100 keV full-size Negative Ion Source prototype of the ITER Neutral Beam Injector, operating at Consorzio RFX in Padova, Italy. The largest Negative Ion Source in the world, SPIDER generates an RF driven plasma from which Deuterium or Hydroge ...

2023

Carbon K-edge x-ray emission spectroscopy of gas phase ethylenic molecules

Majed Chergui, Camila Bacellar Cases Da Silveira, Rebecca Ann Ingle, Luca Longetti, Thomas Roland Barillot

We report on the C K-edge x-ray absorption spectra and the resonant (RXES) and non-resonant (NXES) x-ray emission spectra of ethylene, allene and butadiene in the gas phase. The RXES and NXES show clear differences for the different molecules. Overall both ...

IOP Publishing2022

Beware of beam damage under reaction conditions: X-ray induced photochemical reduction of supported VOx catalysts during in situ XAS experiments

Oliver Kröcher, Davide Ferri, Anna Zabilska, Olga Safonova

In situ X-ray absorption spectroscopy (XAS) is a powerful technique for the investigation of heterogeneous catalysts and electrocatalysts. The obtained XAS spectra are usually interpreted from the point of view of the investigated chemical processes, there ...

ROYAL SOC CHEMISTRY2022

Multiple Surface Site Three-Dimensional Structure Determination of a Supported Molecular Catalyst

Pierrick Berruyer, Moreno Lelli, David Benjamin Roger Antoine Gajan, Zhuoran Wang

The structural characterization of supported molecular catalysts is challenging due to the low density of active sites and the presence of several organic/organometallic surface groups resulting from the often complex surface chemistry associated with supp ...

AMER CHEMICAL SOC2022

Adsorption Behavior of the Coenzyme NADH at the Carbon/ Electrolyte Interface Determined by Neutron Reflectometry

The adsorption behavior of beta-nicotinamide adenine dinucleotide (NADH) at the carbon/electrolyte interface has been studied using a combination of neutron reflectometry (NR) and solution depletion isotherms. Coupling the NR technique with an electrochemi ...

2022

Stabilization of high-spin Mn ions in tetra-pyrrolic configuration on copper

Magalí Alejandra Lingenfelder

By means of Mn-Cu transmetalation, we incorporated Mn atoms in an array of TCNQ (7,7,8,8-tetracyanoquinodimethane) grown on Cu(100), forming a long range ordered and commensurate metal-organic coordination network (MOCN). Preliminary Sn alloying of the Cu( ...

ELSEVIER2021

In-line electronic and structural characterization of reactively sputtered Cu-Co-Mn black spinel oxides

Andreas Schueler, Anna Krammer, Maxime Lagier

Cu-Co-Mn spinel oxide thin films are deposited by reactive magnetron sputtering. The x-ray diffraction (XRD) spectrum suggests a nanocrystalline spinel film when sputtered at approximate to 465 degrees C. In-line scanning tunneling microscopy confirms nano ...

A V S AMER INST PHYSICS2021

Two-dimensional correlation analysis for x-ray photoelectron spectroscopy

Christoph Bostedt, Andre Al Haddad, Thomas Roland Barillot

X-ray photoelectron spectroscopy (XPS) measures the binding energy of core-level electrons, which are well-localised to specific atomic sites in a molecular system, providing valuable information on the local chemical environment. The technique relies on m ...

IOP Publishing2021

Advantages and Limitations of Surface Analysis Techniques on Plasma-Treated Arabidopsis thaliana Seeds

Ivo Furno, Alan Howling, Alexandra Waskow

Surface characterization of plasma-treated seeds has made significant progress over the last decade. Most papers in the literature use scanning electron microscopy (SEM) and contact angle goniometry to investigate surface modifications. However, very few p ...

2021

Studies on the mechanical evolution of compacted bentonite subjected to environmental actions

Jose Antonio Bosch Llufriu

Deep geological disposal is currently the most feasible option for the long-term isolation of radioactive waste, consisting in emplacing the waste into tunnels or drifts excavated at great depths in suitable geological formations. The use of bentonite, a h ...

EPFL2021

Photo- and thermally-induced electronic and structural dynamics in perovskites and transition metal oxides

Oliviero Cannelli

In this thesis, we exploited optical and X-ray pump-probe methods in a synergistic approach to study the interplay of the electronic, spin and structural degrees of freedom in two class of complex systems relevant for solar energy conversion applications: ...

EPFL2021

In situ nanoscale studies of copper-based catalysts for carbon dioxide electroreduction

Karla Banjac

The urgency of climate change demands the simultaneous removal of carbon dioxide from the atmosphere and the transition to renewable energy sources. This aim is realizable through electrochemical reduction of carbon dioxide (CO2RR), which is a promising ro ...

EPFL2021

Electronic structure of pristine and Ni-substituted LaFeO3 from near edge x-ray absorption fine structure experiments and first-principles simulations

Nicola Marzari, Iurii Timrov, Matteo Cococcioni, Artur Braun, Xinyu Zhang, Daniele Passerone, Piyush Agrawal

We present a joint theoretical and experimental study of the oxygen K-edge spectra for LaFeO3 and homovalent Ni-substituted LaFeO3 (LaFe0.75Ni0.25O3), using first-principles simulations based on density-functional theory with extended Hubbard functionals a ...

AMER PHYSICAL SOC2020

Metal-organic framework derived copper catalysts for CO2 to ethylene conversion

Jun Li, Ning Wang, Yun Liu

The electrochemical reduction of CO2 to ethylene provides a carbon-neutral avenue for the conversion of CO2 to value-added fuels and feedstocks, so contributing to the storage of intermittent renewable electricity. The exploration of efficient electrocatal ...

Royal Society of Chemistry2020

White-line evolution in shocked solid Ta evidenced by synchrotron x-ray absorption spectroscopy

Richard Gaal

Time-resolved x-ray absorption experiments have been performed on shocked tantalum. Using a single 100 ps synchrotron x-ray pulse, nanosecond-lived equilibrium states of shocked solid Ta have been measured by L-3-edge absorption spectroscopy. The energy sh ...

2020

Liquid phase in situ spectroscopic investigations of heterogeneous catalysts

Thibault Xavier Florian Fovanna

In this work, we have studied various aspects of catalysts and catalytic processes at the solid-liquid interface, e.g. the reduction of supported PdO, the formation of Pd hydrides, their quantification, the their reactivity in a transient in time-resolved ...

EPFL2020