Ammonia cracking on single-atom catalysts: A mechanistic and microkinetic study

Lu, Xiuyuan and Roldan Martinez, Alberto ORCID: https://orcid.org/0000-0003-0353-9004 2024. Ammonia cracking on single-atom catalysts: A mechanistic and microkinetic study. Applied Catalysis A: General 673 , 119589. 10.1016/j.apcata.2024.119589

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Abstract

Ammonia cracking has been identified as a crucial step to unlocking a sustainable economy. Using the density functional theory, we modeled transition metal single-atom catalysts (SACs) supported on graphene and nitrogen-modified graphene to investigate the catalytic NH3 cracking process. The results showed that (i) N-modified graphene secures the transition metal atoms (M) stronger than C-matrixes, and (ii) structures with three anchoring nitrogens (MN3) are more reactive than MN4 ones. On IrN3 and RuN3 SAC models, the N2 evolution determines the total rate, while, on RhN3-SAC, it is the NH3 dehydrogenation. Temperature-programmed desorption simulations on SACs showed variations compared to extended metal surfaces. Batch reactor simulations were employed to balance the sequence of elementary steps as a function of the temperature, revealing the overall NH3 cracking activity. Results suggested IrN3 and RhN3 are strong candidates for NH3 cracking at temperatures as low as 230 °C.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Chemistry Cardiff Catalysis Institute (CCI)
Publisher:	Elsevier
ISSN:	0926-860X
Funders:	EPSRC
Date of First Compliant Deposit:	21 February 2024
Date of Acceptance:	29 January 2024
Last Modified:	16 Apr 2024 08:58
URI:	https://orca.cardiff.ac.uk/id/eprint/166434

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