Enhancement of the catalytic activity of lithium amide towards ammonia decomposition by addition of transition metals

Brooker-Davies, Caitlin, Makepeace, Joshua ORCID: https://orcid.org/0000-0002-7107-0845 and Wood, Thomas ORCID: https://orcid.org/0000-0002-5893-5664 2023. Enhancement of the catalytic activity of lithium amide towards ammonia decomposition by addition of transition metals. Journal of Ammonia Energy 1 (1) , pp. 46-58. 10.18573/jae.11

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Abstract

The catalytic decomposition of ammonia to hydrogen is a vital process in the use of ammonia as a zero-carbon energy store. However, the viability of current catalyst systems in terms of operating conditions, versatility, and cost efficiency has proven an issue. Catalytic and gravimetric studies were conducted considering mechanistic uncertainty surrounding the enhanced catalytic activity reported for lithium amide and imide composited with transition metals (Cr, Mn, Fe). Gas flow in excess of ammonia decomposition was quantified and used to differentiate the extent of formation of non-stoichiometric lithium imide amide from other competing processes. This analysis showed the initial compositional transition from lithium amide to an imide-rich phase was reduced in temperature by compositing with Mn and Cr, but not with Fe. The system is, therefore, best considered as promoted lithium imide, with Cr and Mn acting to reduce the formation temperature of the active imide-rich phase such that the catalytic activity is enhanced.

Item Type:	Article
Date Type:	Publication
Status:	Published
Publisher:	Cardiff University Press
ISSN:	2752-7735
Funders:	EU Horizon 2020, UKRI
Date of First Compliant Deposit:	10 November 2023
Date of Acceptance:	9 May 2023
Last Modified:	10 Nov 2023 16:11
URI:	https://orca.cardiff.ac.uk/id/eprint/163819

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