Allotrope-dependent activity-stability relationships of molybdenum sulfide hydrogen evolution electrocatalysts
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Date
2024-04-29
Authors
Escalera-López, Daniel
Iffelsberger, Christian
Zlatar, Matej
Novčić, Katarina
Maselj, Nik
Van Pham, Chuyen
Jovanovič, Primož
Hodnik, Nejc
Thiele, Simon
Pumera, Martin
0000-0003-4217-0043Advisor
Referee
Mark
Journal Title
Journal ISSN
Volume Title
Publisher
NATURE PORTFOLIO
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Abstract
Molybdenum disulfide (MoS2) is widely regarded as a competitive hydrogen evolution reaction (HER) catalyst to replace platinum in proton exchange membrane water electrolysers (PEMWEs). Despite the extensive knowledge of its HER activity, stability insights under HER operation are scarce. This is paramount to ensure long-term operation of Pt-free PEMWEs, and gain full understanding on the electrocatalytically-induced processes responsible for HER active site generation. The latter are highly dependent on the MoS2 allotropic phase, and still under debate. We rigorously assess these by simultaneously monitoring Mo and S dissolution products using a dedicated scanning flow cell coupled with downstream analytics (ICP-MS), besides an electrochemical mass spectrometry setup for volatile species analysis. We observe that MoS2 stability is allotrope-dependent: lamellar-like MoS2 is highly unstable under open circuit conditions, whereas cluster-like amorphous MoS3-x instability is induced by a severe S loss during the HER and undercoordinated Mo site generation. Guidelines to operate non-noble PEMWEs are therefore provided based on the stability number metrics, and an HER mechanism which accounts for Mo and S dissolution pathways is proposed. The stability of non-noble catalysts is key for their use in proton exchange membrane water electrolysers. Here, authors study activity-stability relationships of MoSx allotropes for H2 production, reporting allotrope-dependent stabilities and dissolution pathways, and propose operation guidelines.
Description
Citation
NATURE COMMUNICATIONS. 2024, vol. 15, issue 1, p. 1-13.
https://www.nature.com/articles/s41467-024-47524-w
https://www.nature.com/articles/s41467-024-47524-w
Document type
Peer-reviewed
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Published version
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en