ROCK: A Beamline Tailored for Catalysis and Energy-Related Materials from ms Time Resolution to µm Spatial Resolution

Abstract

Assessing the structure-activity relationship in materials used as catalysts or for energy storage is a major challenge in order to provide efficiency, durability, clean processes and sustainable energy. Xray Absorption Spectroscopy (XAS) is a widely used technique to this aim, as it can provide structural and electronic information about the active elements of these materials. Many XAS beamlines have improved their performances to provide time-resolved information about evolving materials under real working conditions. To this end, Quick-EXAFS (QEXAFS) monochromators were installed at SOLEIL synchrotron on the SAMBA beamline in 2009 [1]. The excellent performances for operando studies of heterogeneous catalysts achieved on SAMBA [2] were very attractive for the scientific community, although the SAMBA's optical layout was optimized for its sagitally-focusing doublecrystal monochromator and could not offer more than 10 11 ph/s flux at the best at the sample position when using the QEXAFS ones. Based on the experience gained on SAMBA, the construction of a new beamline dedicated and optimized for the QEXAFS monochromators was decided and granted in 2011 by the French Agence Nationale de la Recherche in the framework of the national "Investissements d'Avenir" program (ANR-10-EQX-45-01). In order to propose a beamline tailored for operando characterization of catalytic and energy related materials, both experts from the synchrotron world and from the scientific domains were gathered from the start of the project. The consortium, leaded by SOLEIL, involved three major French scientific actors of the heterogeneous catalysis and materials for the energy communities: the

Multifunctional Catalyst Combination for the Direct Conversion of CO2 to Propane

“…XAS measurements were performed at the Quick-XAS ROCK 19 beamline of the French synchrotron SOLEIL. K-edges of Pd and Zn were separately collected in transmission mode.…”

CO2hydrogenation to methanol and hydrocarbons over bifunctional Zn-doped ZrO2/zeolite catalysts

“…This becomes especially relevant, in view of recent findings highlighting inter-phase ion exchange phenomena in combined systems obtained by physically mixing acid zeolites and Zn-containing hydrogenation catalysts. 10 To obtain fully comparable information at Zr and Zn K-edges, we measured the two absorption edges quasi-simultaneously during the same experiment, exploiting the unique capability of the ROCK beamline 53 of the SOLEIL synchrotron (see section 2.2.5 for details).…”

“…XAS measurements on the combined ZrZn-X/ZSM-5 systems. Zn and Zr K-edge operando XAS experiments in transmission mode were performed at the Quick-XAS ROCK beamline 53 (Rocking Optics for Chemical Kinetics) of the French Synchrotron SOLEIL. A quasi-simultaneous scanning of Zr (17.7-19 keV) and Zn (9.3-10.7 keV) K-edges was possible thanks to the quick edge-jump feature of the ROCK beamline.…”

“…A quasi-simultaneous scanning of Zr (17.7-19 keV) and Zn (9.3-10.7 keV) K-edges was possible thanks to the quick edge-jump feature of the ROCK beamline. 53 However, jumping between two absorption edges dictated to find a compromise between the sample thickness and the absorption length of both edges. Hard X-ray XAS allows monitoring with element-selectivity of the bulk properties of the combined systems and the ZrZn-X/zeolite interaction under operando conditions.…”

XANES spectroscopy for the clinician

“…The SOLEIL synchrotron can acquire XANES spectra on several beamlines. Some offer very fast acquisition capabilities (less than one second, compared to conventional XANES which usually takes several minutes) allowing phase transitions or chemical reactions to be followed using quick-EXAFS, as on ROCK (Rocking Optics for Chemical Kinetics) which operates between 4.5 and 40 keV [137], and ODE (Optique Dispersive EXAFS), using dispersive EXAFS which operates between 3.5 and 25 keV [138]. Up to now, most biomedical research has been based on XANES spectroscopy performed on the DiffAbs beamline [139], where experiments can be performed using a macro (300 µm) or micro beam size (10 × 10 µm 2 ) and an energy range between 3 and 19 keV.…”