Solutal Marangoni effect determines bubble dynamics during electrocatalytic hydrogen evolution

Sunghak Park, Luhao Liu, Çayan Demirkır, Onno van der Heijden, Detlef Lohse, Dominik Krug*, Marc T.M. Koper*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

33 Citations (Scopus)
122 Downloads (Pure)

Abstract

Understanding and manipulating gas bubble evolution during electrochemical water splitting is a crucial strategy for optimizing the electrode/electrolyte/gas bubble interface. Here gas bubble dynamics are investigated during the hydrogen evolution reaction on a well-defined platinum microelectrode by varying the electrolyte composition. We find that the microbubble coalescence efficiency follows the Hofmeister series of anions in the electrolyte. This dependency yields very different types of H2 gas bubble evolution in different electrolytes, ranging from periodic detachment of a single H2 gas bubble in sulfuric acid to aperiodic detachment of small H2 gas bubbles in perchloric acid. Our results indicate that the solutal Marangoni convection, induced by the anion concentration gradient developing during the reaction, plays a critical role at practical current density conditions. The resulting Marangoni force on the H2 gas bubble and the bubble departure diameter therefore depend on how surface tension varies with concentration for different electrolytes. This insight provides new avenues for controlling bubble dynamics during electrochemical gas bubble formation. [Figure not available: see fulltext.].

Original languageEnglish
Pages (from-to)1532-1540
Number of pages9
JournalNature chemistry
Volume15
Issue number11
Early online date10 Aug 2023
DOIs
Publication statusPublished - Nov 2023

Keywords

  • 2023 OA procedure

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