Gas Bubble Stabilization Limits Tetraalkylammonium-Enhanced Hydrogen Evolution

ACS Catalysis, vol. 16, pp. 5796–5804

Abstract

High Resolution Image Download MS PowerPoint Slide Pt is the most active single-metal HER catalyst in acidic media, but its performance drops sharply in alkaline electrolytes. While recent studies have shown that tetraalkylammonium (TAA + ) cations can enhance alkaline HER by restructuring interfacial water, their role under bubble-forming, high-current conditions remains unclear. Here we show that tetrabutylammonium (TBA + ) exerts a dual, potential-dependent effect on Pt: it boosts HER rates at low overpotentials but suppresses them at higher overpotentials. Using microelectrodes with high-speed imaging, we track microbubble formation, growth and detachment, and find that TBA + stabilizes bubbles through adsorption at multiple interfaces, including the electrode and surrounding insulator, leading to persistent surface blockage via pinning and coalescence. Rotating disk electrode measurements confirm that the resulting activity loss originates from mass transport limitations rather than intrinsic kinetics. These findings clarify the role of organic cations in governing gas evolution dynamics and highlight the need to account for interfacial bubble effects when interpreting alkaline HER activity.

Authors 7

1. Julia Fernández‐Vidal Aachen Leiden Institute of Chemistry

   Leiden University

   Affiliation as printed

   Leiden Institute of Chemistry

   Leiden University

2. Kathryn J. Vannoy Aachen Leiden Institute of Chemistry

   Leiden University

   Affiliation as printed

   Leiden Institute of Chemistry

   Leiden University

3. Aleksandr Bashkatov Aachen

   Max Planck Society · Max Planck University of Twente Center for Complex Fluid Dynamics · RWTH Aachen University · University of Twente

   Affiliation as printed

   Institute of Aerodynamics and Chair of Fluid Mechanics

   Physics of Fluids Group, Max Planck Center for Complex Fluid Dynamics

   RWTH Aachen University

   University of Twente

4. Dominik J. Krug Aachen

   Max Planck Society · Max Planck University of Twente Center for Complex Fluid Dynamics · RWTH Aachen University · University of Twente

   Affiliation as printed

   Institute of Aerodynamics and Chair of Fluid Mechanics

   Physics of Fluids Group, Max Planck Center for Complex Fluid Dynamics

   RWTH Aachen University

   University of Twente

5. Onno van der Heijden Aachen Leiden Institute of Chemistry

   Leiden University

   Affiliation as printed

   Leiden Institute of Chemistry

   Leiden University

6. Detlef Lohse

   Max Planck Society · Max Planck Institute for Dynamics and Self-Organization · Max Planck University of Twente Center for Complex Fluid Dynamics · University of Twente

   Affiliation as printed

   Max Planck Institute for Dynamics and Self-Organization

   Physics of Fluids Group, Max Planck Center for Complex Fluid Dynamics

   University of Twente

7. Marc T. M. Koper corresponding Aachen Leiden Institute of Chemistry

   Leiden University

   Affiliation as printed

   Leiden Institute of Chemistry

   Leiden University