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Our latest work on X-ray tomographic diffraction imaging of operating dense ceramic hollow-fibre catalytic membrane reactors (CMRs)

You can see our latest work on X-ray tomographic diffraction imaging of operating dense ceramic hollow-fibre catalytic membrane reactors (CMRs) – “Real-time tomographic diffraction imaging of catalytic membrane reactors for the oxidative coupling of methane” in Catalysis Today. The paper is a result of a collaboration between scientists at UCL Chemistry, Finden, ESRF,  VITO and ISIS Neutron and Muon Source.

Real time tomographic diffraction figHighlights include:
  • Synchrotron X-ray diffraction computed tomography applied to three packed bed catalytic membrane reactors.
  • The solid-state evolution of catalysts and membranes is tracked under operating conditions.
  • A new crystal structure model of BaCo0.4Fe0.4Zr0.2O3-δ (BCFZ) is suggested and used for the diffraction data analysis

 

 

Catalytic membrane reactors have the potential to render the process of oxidative coupling of methane economically viable. Here, the results from operando XRD-CT studies of three different catalytic membrane reactors, employing BaCo0.4Fe0.4Zr0.2O3-δ (BCFZ) and La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) perovskite membranes with Mn-Na-W/SiO2 and La-promoted Mn-Na-W/SiO2 catalysts, are presented. It is shown that synchrotron X-ray tomographic diffraction imaging allows the extraction of spatially-resolved diffraction information from the interior of these working catalytic membrane reactors and makes it possible to capture the evolving solid-state chemistry of their components under various operating conditions (i.e. temperature and chemical environment).

Read the paper at https://doi.org/10.1016/j.cattod.2020.05.045

Our paper on the first region-of-interest high resolution X-ray diffraction computed tomography experiment of a Si-graphite electrode used for Li-ion battery applications has been published in Nano Letters

Our scientists’ new work on Si-graphite electrodes used for Li-ion battery applications with high resolution in situ X-ray chemical imaging has been published in a new paper, “Spatially Resolving Lithiation in Silicon–Graphite Composite Electrodes via in Situ High-Energy X-ray Diffraction Computed Tomography” in Nano Letters. The work was performed with Donal Finegan from the National Renewable Energy Laboratory and in collaboration with a team from the Electrochemical Innovation Lab (EIL) from UCL Chemical Engineering using ESRF’s ID15A beamline.

Optimizing the chemical and morphological parameters of lithium-ion (Li-ion) electrodes is extremely challenging, due in part to the absence of techniques to construct spatial and temporal descriptions of chemical and morphological heterogeneities. In this work, we present the first demonstration of combined high-speed X-ray diffraction (XRD) and XRD computed tomography (XRD-CT) to probe, in 3D, crystallographic heterogeneities within Li-ion electrodes with a spatial resolution of 1 μm. The local charge-transfer mechanism within and between individual particles was investigated in a silicon(Si)−graphite composite electrode. High-speed XRD revealed charge balancing kinetics between the graphite and Si during the minutes following the transition from operation to open circuit. Subparticle lithiation heterogeneities in both Si and graphite were observed using XRD-CT, where the core and shell structures were segmented, and their respective diffraction patterns were characterized.

Battery diagram

Figure: (a) XRD-CT slice taken at the beginning of the charge step showing a phase-distribution map of LiC12 (red), crystalline Si (green), and lithium silicides LixSi (blue). According to additive colour mixing, the colour teal represents a mixture of green (Si) and blue (lithiated Si). (b) Magnified regions of interest showing large particles of LixSi phase with crystalline Si cores (1-3) and smaller LixSi particles (4) interspersed in the graphite matrix. The yellow arrow highlights what looks to be evidence of delamination from a crystalline Si core.

Read more about it at https://www.esrf.eu/home/news/spotlight/content-news/spotlight/spotlight346.html

Read the article at https://pubs.acs.org/doi/full/10.1021/acs.nanolett.9b00955

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