Bai, Zhongze;
Luo, Kai H;
(2025)
Mechanisms for interactions of H₂S and Hg⁰ with oxygen carrier LaMnO₃ during chemical looping combustion: a DFT study.
Carbon Capture Science & Technology
, 16
, Article 100480. 10.1016/j.ccst.2025.100480.
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Abstract
Mercury (Hg0) and hydrogen sulphide (H2S) inevitably coexist during chemical looping combustion (CLC) of coal or coal-derived syngas. Their interactions with oxygen carriers are critical to understanding mercury transformation and removal. In this study, density functional theory (DFT) calculations were conducted to investigate the reaction mechanisms among Hg0, H2S, and the LaMnO3(010) surface (a Mn-based perovskite with excellent redox properties and thermal stability). Results show that H2S, HS, and S chemisorb on the surface via stable S-Mn bonding, while HgS forms through parallel adsorption involving both Hg-Mn and S-Mn bonds. The preferred H2S decomposition pathway involves simultaneous dehydrogenation to produce S* and H*, with H* subsequently forming H2 or H2O. Among the examined reaction routes, Hg0 reacts most favourably with S* via the Eley-Rideal mechanism, exhibiting the lowest energy barrier of 2.939 eV. These findings offer atomic-level insight into Hg-S interactions on LaMnO3 surfaces and provide a theoretical foundation for the rational design of perovskite-based oxygen carriers (OCs) capable of efficient simultaneous mercury capture and sulphur stabilization, thereby advancing integrated Hg0 and HgS removal strategies in CLC systems.
| Type: | Article |
|---|---|
| Title: | Mechanisms for interactions of H₂S and Hg⁰ with oxygen carrier LaMnO₃ during chemical looping combustion: a DFT study |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1016/j.ccst.2025.100480 |
| Publisher version: | https://doi.org/10.1016/j.ccst.2025.100480 |
| Language: | English |
| Additional information: | Copyright © 2025 The Author(s). Published by Elsevier Ltd on behalf of Institution of Chemical Engineers (IChemE). This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). |
| Keywords: | Mercury, H2S, Density functional theory, Reaction mechanisms, Chemical looping combustion |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Mechanical Engineering |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10213555 |
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