Free-energy analysis of bubble nucleation on electrocatalytic surfaces

Xie Q, Malgaretti P, Aouane O, Thiele S, Harting J (2026)

Publication Type: Journal article

Publication year: 2026

Journal

Physical Chemistry Chemical Physics Royal Society of Chemistry

DOI: 10.1039/d6cp00998k

Abstract

Bubble nucleation at catalyst surfaces plays a critical role in the operation of electrolyzers. However, achieving controlled bubble nucleation remains challenging due to limited understanding of the underlying mechanisms. Here, we present a free-energy model that quantitatively predicts both the activation energy and critical nucleus size of bubbles at given supersaturation, temperature, pressure, and surface wettability. We find that the activation energy ΔGmax decreases with increasing supersaturation ζ, following a power-law scaling of ΔGmax ∼ ζ−2, while the critical nucleus radius Rc scales as Rc ∼ ζ−1. Our theoretical predictions for the critical nucleus radius of hydrogen, oxygen and nitrogen bubbles are in quantitative agreement with experimental measurements. Finally, we present a simple model that couples gas diffusion and electrochemical reaction kinetics to determine the maximum gas supersaturation at a given current density. Our results advance the fundamental understanding of bubble nucleation at catalyst surfaces and provide practical guidelines for catalyst layer design to improve the performance of electrolyzers.

Involved external institutions

Forschungszentrum Jülich / Research Centre Jülich (FZJ) DE Germany (DE)

How to cite

APA:

Xie, Q., Malgaretti, P., Aouane, O., Thiele, S., & Harting, J. (2026). Free-energy analysis of bubble nucleation on electrocatalytic surfaces. Physical Chemistry Chemical Physics. https://doi.org/10.1039/d6cp00998k

MLA:

Xie, Qingguang, et al. "Free-energy analysis of bubble nucleation on electrocatalytic surfaces." Physical Chemistry Chemical Physics (2026).

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