Electroconvective instability in water electrolysis: an evaluation of electroconvective patterns and their onset features

Abstract

In electrochemical systems, an understanding of the underlying transport processes is required to aid in their better design. This includes knowledge of possible near-electrode convective mixing that can enhance measured currents. Here, for a binary acidic electrolyte in contact with a platinum electrode, we provide evidence of electroconvective instability during electrocatalytic proton reduction. The current-voltage characteristics indicate that electroconvection, visualized with a fluorescent dye, drives current densities larger than the diffusion transport limit. The onset and transition times of the instability do not follow the expected inverse-square dependence on the current density, but, above a bulk-reaction-limited current density are delayed by the water dissociation reaction. The dominant size of the electroconvective patterns is also measured and found to vary as the diffusion length scale, confirming previous predictions on the size of electroconvective vortices.

References in corpus (5)

• Overlimiting current in a microchannel
• Diffuse-Charge Effects on the Transient Response of Electrochemical Cells
• Dynamics of microvortices induced by ion concentration polarization
• On the coupling between buoyancy forces and electroconvective instability near ion-selective surfaces
• Theory of linear sweep voltammetry with diffuse charge: unsupported electrolytes, thin films, and leaky membranes

Cited by in corpus (4)

• Life beyond Fritz: On the detachment of electrolytic bubbles
• The effect of buoyancy driven convection on the growth and dissolution of bubbles on electrodes
• Modulated Collective Behaviors and Condensation of Bacteria
• To jump or not to jump: Adhesion and viscous dissipation dictate the detachment of coalescing wall-attached bubbles