Elucidating the rate-determining step of ammonia decomposition on Ru-based catalysts using ab initio-grounded microkinetic modeling

Shekhar R. Kulkarni, Natalia Realpe, Attada Yerrayya, Vijay Kumar Velisoju, Salvador Sayas, Natalia Morlanes, Jose Cerillo, Sai P. Katikaneni, Stephen N. Paglieri, Bandar Solami, Jorge Gascon, Pedro Castaño*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

7 Scopus citations


Decarbonizing the current energy system requires a shift toward renewable energy sources, among which ammonia is a remarkable hydrogen carrier. However, developing an efficient process for the catalytic decomposition of ammonia is still required. Here, we propose a combined modeling-experimental approach to elucidate the rate-determining step in ammonia decomposition on Ru-based catalysts. We characterize and test two supported Ru and Ru-K catalysts in the reaction. We develop several microkinetic models based on ab initio calculations considering different rate-determining steps and validate them with the results of packed bed experiments. For the method validation, we develop a fitting strategy based on modifying the lowest number of parameters from those initially obtained theoretically. A good agreement between the simulated and measured experimental ammonia conversions is obtained, thus widening our understanding of this critical hydrogen production process. The approach presented here allows distinguishing the rate-determining step accurately, and it could be applied to other catalytic systems used in ammonia decomposition to avoid over-relying on empirical models.

Original languageEnglish (US)
Pages (from-to)2026-2037
Number of pages12
JournalCatalysis Science and Technology
Issue number7
StatePublished - Feb 8 2023

Bibliographical note

Funding Information:
The authors gratefully acknowledge the financial support provided by Saudi Aramco and the resources and facilities provided by the King Abdullah University of Science and Technology (KAUST). The authors acknowledge the KAUST Supercomputing Laboratory (KSL) for providing high-performance computational resources.

Publisher Copyright:
© 2023 The Royal Society of Chemistry.

ASJC Scopus subject areas

  • Catalysis


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