ISIS Neutron and Muon Source Data Journal

Diffusion of hydrogen through potassium and sodium hydride intercalated graphite

Abstract: The principal objective of this proposal is to fully characterise the mobility of hydrogen in KH and NaH intercalated graphite, as relevant to ammonia synthesis catalysis. These materials have demonstrated excellent performance as low temperature ammonia synthesis catalysts without use of transition metals. Preliminary elastic and inelastic fixed window scans have been performed on a KH graphite type catalyst via an Xpress study at the ILL. The results indicate hydrogen mobility above 210 K due to a decrease in elastic incoherent scattering intensity upon warming from 2 to 400 K . However, limited time and poor statistics prevented full characterisation of the diffusion mechanism (i.e. frequency and geometry of motion). To better understand these preliminary test results we now request four days on IRIS, to perform a finite number of a high statistics S(Q,?) measurements at key temperatures; the temperatures chosen being guided by an accompanying elastic fixed window scan up to 570 K. We propose to study two systems for comparison; (1) KH intercalated graphite (2) NaH intercalated graphite. The aim is to extract and compare information about the mobility of hydrogen already present in these two catalysts and relate this to the catalytic ability. If successful, this study will be a precursor to a future proposal in which hydrogen and nitrogen gas flow will simulate ammonia synthesis conditions.

Principal Investigator: Professor Bill David
Experimenter: Ms Juliette Verschoor
Experimenter: Ms Emma Perry
Experimenter: Dr Tom Wood
Local Contact: Dr Mark Telling

DOI: 10.5286/ISIS.E.RB2420448

ISIS Experiment Number: RB2420448

Publisher: STFC ISIS Neutron and Muon Source

Data format: RAW/Nexus
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Data Citation

The recommended format for citing this dataset in a research publication is as:
[author], [date], [title], [publisher], [doi]

For Example:
Professor Bill David et al; (2025): Diffusion of hydrogen through potassium and sodium hydride intercalated graphite, STFC ISIS Neutron and Muon Source, https://doi.org/10.5286/ISIS.E.RB2420448

Data is released under the CC-BY-4.0 license.