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New work on sustainable iron-based oxygen carriers for hydrogen production published

Graphical abstract

Finden Ltd collaborated with Yoran De Vos (Ghent University) to look at the evolution of an Fe-based oxygen carrier under operando conditions. The project has resulted in a paper published in the International Journal of Greenhouse Gas Control titled, Sustainable iron-based oxygen carriers for hydrogen production – Real-time operando investigation.

In this work, a spray-dried Fe-based oxygen carrier with an in situ generated Mg1-xAl2-yFex+yO4-support was investigated during packed-bed chemical looping operation with methane at 900 °C. The evolution of the solid-state chemistry taking place in the oxygen carrier material was investigated in real-time with synchrotron X-ray diffraction while the spatial distribution of the phases was investigated using X-ray diffraction computed tomography (XRD-CT). These measurements revealed that some Fe-cations were systematically taken up and released from the spinel support. This take-up and release was shown to be strongly related with the oxidation state of the active phase. Although this take-up and release of Fe-cations decreased the amount of Fe-oxides active in the chemical looping process, the oxygen transfer capacity was still sufficiently high. The microstructure of the oxygen carriers along the length of the packed reactor bed was also investigated with scanning electron microscopy (SEM). The experiments indicate that the MgFeAlOx support with an extra Fe-based active phase is a promising material for oxygen carriers, as it forms a sustainable non-toxic, stable and green alternative to the typical Ni-based oxygen carriers, for hydrogen generation by chemical looping.

The work was done at the The European Synchrotron (ESRF) and research partners included; Flemish Institute for Technological Research (VITO), Ghent University and University College London.

Read the paper at https://www.sciencedirect.com/science/article/abs/pii/S175058361930146X.

Our paper on the first X-ray diffraction tomography experiment of real-life size micro-tubular SOFC has been published in Nature Communications

Figure various micro-monolithic anode supports after sintering

Various micro-monolithic anode supports after sintering at 1450 °C. SEM images of central-axis-view of: a 3, b 4, and c 7 channels; Cross-sectional images of d sponge between the shell and two channels in the 7-channel anode, e sponge between the central channel and surrounding two channels in the 7-channel anode; f close-up image of anode/electrolyte interface

Our new work on a state-of-the-art SOFC has been published in a paper Design of next-generation ceramic fuel cells and real-time characterization with synchrotron X-ray diffraction computed tomography in Nature Communications.

Solid oxide fuel cells offer a clean and efficient means of producing electricity through a variety of fuels. However, miniaturization of cell dimensions for portable device applications remains a challenge, as volumetric power densities generated by readily-available planar/tubular ceramic cells are limited. In our work, we demonstrate a concept of ‘micro-monolithic’ ceramic cell design and evaluate the mechanical robustness and structural integrity of this design, for the first time, with synchrotron X-ray diffraction computed tomography. The successful miniaturization results in an exceptional power density of 1.27 W cm−2 at 800 °C, which is among the highest reported. This holistic design incorporates both mechanical integrity and electrochemical performance, leading to mechanical property enhancement and representing an important step toward commercial development of portable ceramic devices with high volumetric power (>10 W cm−3), fast thermal cycling and marked mechanical reliability. This is also the first time a real-life size solid oxide fuel cell has been investigated in situ demonstrating that such experiments are now possible, adding a very powerful characterisation tool for the SOFC community in general.

The synchrotron experiments were conceived, designed and performed by Dr Antony Vamvakeros and Dorota Matras in collaboration with a team from the Electrochemical Innovation Lab (EIL) from UCL Chemical Engineering using ESRF’s ID15A beamline using a state-of-the-art SOFC designed by Imperial College.

Read the full article at https://www.nature.com/articles/s41467-019-09427-z

Read more about it at http://www.esrf.eu/sites/www/home/news/general/content-news/general/real-time-characterisation-of-a-new-miniature-honeycomb-fuel-cell-shows-its-outstanding-properties.html

Tomographic software nDTomo released!

example of XRD-CT sinogram data volume exploration imageThe nDTomo software is now publicly available for download. Developed by our research scientist Dr. Antony Vamvakeros and primarily designed for processing XRD-CT data, it can be used for other tomographic techniques as well. The software suite contains GUIs for the acquisition, pre-processing and analysis of X-ray chemical tomography data. Download it at

A masterpiece on a on a pin head

Steve and painting sample photoFinden Ltd’s work with microfocus X-ray beams at Diamond Light Source recently appeared in an article in The Telegraph, “Old Master paintings shown to be ‘crusting over’ by microscope 10 billion times brighter than the Sun.” Dr. Stephen Price explains in the article,

“We were able to plot the different chemistry from the surface down to the base layer where the canvas would be.

“Knowing some of the more eventful history of the painting, such as fire damage, led us to work out what had caused the chemistry change.”

Excerpt from article. Read the full article at https://www.telegraph.co.uk/news/2019/01/26/old-master-paintings-shown-crusting-microscope-10-billion-times/

His work has also appeared on the Physics World website,  “Diamond Light Source – when a tool becomes a gem”.

“Stephen Price, a researcher at Finden and formerly a Diamond Light Source scientist, is currently working with the Rijksmuseum in Amsterdam on a sample of Rembrandt’s painting “Homer”, which dates back to 1663. As he explains, the sample is of a white bloom or crust that forms on the painting despite the best efforts of conservationists. His aim has been to identify the chemistry of the crust and hopefully determine how to prevent such crusts forming.

Using the microfocus X-ray beam at Diamond to scan the sample at different angles, they were able to show how the lead paint had reacted with atmospheric pollutants including sulphur dioxide, which was forming the white crust disfiguring the painting. “Using this information the conservation team at the Rijks can investigate further how to prevent and reverse this degradation process,” says Price.”

Excerpt from article. Read the full article at Physics World.

We have just published an article relating to the Homer painting – Unravelling the spatial dependency of the complex solid-state chemistry of Pb in a paint micro-sample from Rembrandt’s Homer using XRD-CT – Chemical Communications (RSC Publishing). Read more about this exciting work at https://pubs.rsc.org/en/content/articlehtml/2019/cc/c8cc09705d

5D operando tomographic diffraction imaging of a catalyst bed

Our paper on 5D operando tomographic diffraction imaging of a catalyst bed has been published online by Nature Communications, volume 9, Article number: 4751 (2018)

We report the results from the first 5D tomographic diffraction imaging experiment of a complex Ni–Pd/CeO2–ZrO2/Al2O3 catalyst used for methane reforming. This five-dimensional (three spatial, one scattering and one dimension to denote time/imposed state) approach enabled us to track the chemical evolution of many particles across the catalyst bed and relate these changes to the gas environment that the particles experience. Rietveld analysis of some 2 × 106 diffraction patterns allowed us to extract heterogeneities in the catalyst from the Å to the nm and to the μm scale (3D maps corresponding to unit cell lattice parameters, crystallite sizes and phase distribution maps respectively) under different chemical environments. We are able to capture the evolution of the Ni-containing species and gain a more complete insight into the multiple roles of the CeO2-ZrO2 promoters and the reasons behind the partial deactivation of the catalyst during partial oxidation of methane.

Read the full article at https://doi.org/10.1038/s41467-018-07046-8