X-ray spectroscopy for chemistry in the 2-4 keV energy regime at the XMaS beamline: ionic liquids, Rh and Pd catalysts in gas and liquid environments, and Cl contamination in γ-Al₂O₃

Abstract

Synopsis:The performance of the XMaS beamline for soft X-ray spectroscopy in the 2-4 keV range is assessed with particular relation to in situ studies of functional materials and their chemistry. X-ray spectroscopy for chemistry in the 2-4 keV energy regime at the XMaS beamline: ionic liquids, Rh and Pd catalysts in gas and liquid environments, and Cl contamination in c-Al 2 O 3 How to cite your article in pressYour article has not yet been assigned page numbers, but may be cited using the doi:Thompson, P.B.J., Nguyen, B.N., Nicholls, R., Bourne, R.A., Brazier, J.B., Lovelock, K.R.J., Brown, S.D., Wermeille, D., Bikondoa, O., Lucas, C.A. et al. (2015). J. Synchrotron Rad. 22, doi:10.1107/S1600577515016148.You will be sent the full citation when your article is published and also given instructions on how to download an electronic reprint of your article. Proof instructionsProof corrections should be returned by 22 September 2015. After this period, the Editors reserve the right to publish your article with only the Managing Editor's corrections. Please(1) Read these proofs and assess whether any corrections are necessary.(2) Check that any technical editing queries highlighted in bold underlined text have been answered. (3) Send corrections by e-mail to tw@iucr.org. Please describe corrections using plain text, where possible, giving the line numbers indicated in the proof. Please do not make corrections to the pdf file electronically and please do not return the pdf file. If no corrections are required please let us know.If you wish to make your article open access or purchase printed offprints, please complete the attached order form and return it by e-mail as soon as possible. Thumbnail image for contents pageFiles: s/rv5038/rv5038.3d s/rv5038/rv5038.sgml RV5038 FA IU-1517/10(15)9 1516/52(15)9 () RV5038 http://dx.doi.org/10.1107/S1600577515016148 1 of 14 The 2-4 keV energy range provides a rich window into many facets of materials science and chemistry. Within this window, P, S, Cl, K and Ca K-edges may be found along with the L-edges of industrially important elements from Y through to Sn. Yet, relative to those that cater for energies above ca. 4-5 keV, there are relatively few resources available for X-ray spectroscopy below these energies. In addition, in situ or operando studies become to varying degrees more challenging than at higher X-ray energies due to restrictions imposed by the lower energies of the X-rays upon the design and construction of appropriate sample environments. The XMaS beamline at the ESRF has recently made efforts to extend its operational energy range to include this softer end of the X-ray spectrum. In this report the resulting performance of this resource for X-ray spectroscopy is detailed with specific attention drawn to: understanding electrostatic and charge transfer effects at the S K-edge in ionic liquids; quantification of dilution limits at the Cl K-and Rh L 3 -edges and structural equilibria in solution; in vacuum deposition and reduction of [Rh I (CO) 2 Cl] 2 to -Al 2 ...

Effect of retained chlorine in ENCAT™ 30 catalysts on the development of encapsulated Pd: insights from in situ Pd K, L3 and Cl K-edge XAS

“…This allowed us to address these systems from the perspectives of the Cl K and Pd L 3 -edges using a recently developed reactor [21] that permits the study of solids in liquid flows at X-ray energies in the 2-4 keV region whilst retaining the overall approach employed in the reactor studies made at the Pd K-edge (24.35 keV). Figure 2 shows the Cl K-edge XANES obtained from each sample in their as-received state and, for the two ENCAT™ 30 NP samples (batch II and batch III), after This exercise in quantification of the degree to which the Pd in any of these Cl containing ENCAT™ samples exists in the reduced state likely overestimates the levels of Pd 0 , given the sensitivity of the Pd 0 XANES to particle size ( Figure 3).…”

“…The latter was configured in standard fluorescence yield geometry in the horizontal plane at 9° to the incoming X-ray beam and at 45° to the sample that was held inside a purpose built chamber described in [21].…”

Effects of Cl on the reduction of supported PdO in ethanol/water solvent mixtures

“…An equally plausible explanation is the displacement of some of the Cl from the Pd to Al sites on the support. At this juncture, we may surmise that the first consequence of the wetting of all the samples with ethanol-water is to remove a proportion of the Cl directly methods we have recently developed at the XMaS beamline at the ESRF [30]. Figure 3 shows the results for the dry samples, which clearly indicated the amounts of Cl retained in these catalysts -relative to the Pd loading -is considerably higher in the 1 wt-% case compared to the 5 and 10 wt-% cases.…”

“…For comparison, the data was compared to an equivalent, Pd nitrate-derived system (bottom trace), measured in the absence of solvent to confirm that the Al 2 O 3 used is, in fact, chlorine free, having previously found that certain other aluminas [30] contain considerable levels of chlorine that can interact with metals deposited. Beyond this, we may see that after having been wetted at room temperature, the residual chlorine that remains in the sample is not subsequently removed, or change significantly, through subsequent heating under the solvent flow.…”

“…A description of the overall setups and methodologies employed can be found in a previous publication [30]. In the measurements presented here acquisition times were typically 5-10 s/point through a 5 μm thick polyethylene window.…”