An inherently leakage-free inverted rotating disk electrode (IRDE) design

Abstract

In electrochemistry, rotating disk electrodes (RDE) are commonly used for the investigation of different electrochemical reaction regimes. The defined mass transfer conditions allow the investigation of rate limiting steps such as adsorption, diffusion or electron transfer. However, when gaseous reaction products are formed, they pose a challenge for a conventional experimental setup, as these gases accumulate on the electrode surface and hinder electrode processes. In this work, a novel experimental setup for an inverted rotating disk electrode (IRDE) cell suitable for the investigation of photoelectrochemical processes is presented. The rotation is achieved through magnetic coupling of magnets inside and outside the cell. This cell design yields construction-inherent leak tightness since the electrolyte reservoir is free from openings on the bottom and sides. Stable electric contact is provided through a spring-loaded tip. The vertical flow profile in the newly developed IRDE was simulated at different rotation speeds using computational fluid dynamics (CFD). The geometry of the cell was adapted in several iterative steps. The final experimental setup was validated comparing the well-studied oxidation of ferrocyanide in the new IRDE setup to measurements in a conventional RDE setup and literature results in a speed range from 100 to 1600 rpm.