Engineering hydrogen-evolving electrodes through multiscale modeling of multiple bubble nucleation, bubble interactions, and coalescence-induced detachment
Year: 2026
Type: article
Abstract: Electrochemical water splitting is strongly influenced by hydrogen bubble dynamics, as bubbles block active sites and contribute to additional overpotential losses on electrodes. Here, we present a multiscale numerical framework that sequentially connects nanoscale bubble nucleation with microscale growth, interaction, and coalescence-induced detachment. The results reveal a trade-off between increasing nucleation-site density and minimizing diffusion-field overlap between neighboring bubbles. Favorable cavity geometries reduce the nucleation overpotential by approximately 15–40% relative to the smallest normalized cavity sizes considered. Increasing the active nucleation-site density from 2 to 8% introduces only 2% additional current loss, whereas increasing the density to 30% raises the current loss to about 40%, indicating that excessive cavity densities become electrochemically unfavorable. These findings identify inter-cavity spacing as a key design parameter governing the balance between nucleation enhancement and transport losses. At the microscale, simulations show that bubble coalescence can induce detachment below the buoyancy-controlled limit. We introduce a design map that shows the wettability threshold for bubble removal can vary from super-aerophobic surfaces with a contact angle of 5° to aerophobic surfaces with a contact angle of 30°. The proposed framework provides physics-based design guidelines for hydrogen-evolving electrodes that simultaneously promote bubble generation and accelerate bubble removal.
Source: Journal of Power Sources
Institutions: University of Toronto, University of Milano-Bicocca
Language: English
Field: Energy
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,230
OpenAlex ID: W7204646850