Upcycling old hard drives into polishing machines and rotating disk electrodes

Following technological evolutions, commercial electrochemical devices are now very compact, but often hard to repair, so that we observe an increase of open-source electrochemical hardware. In this paper, we exploit the former hard drive technology to recycle the brushless motor in order to build a polishing machine and a rotating disk electrode (RDE). Each step of the construction is detailed. The RDE performance is evaluated by linear sweep voltammetry of the classical ferrocenedimethanol redox system. Quantification thanks to the Levich equation provides a diffusion coefficient of ferrocenedimethanol of (4.6 ± 1) × 10⁻¹⁰ m² s⁻¹ in aqueous potassium chloride electrolyte, which is close to the literature, thus validating home-made RDE. Using these devices with the PassStat, an open-source potentiostat allows to build an electrochemical set-up at a very reduced price (less than 150 € for the three devices). The approach will be of specific interest for teaching instrumentation and for countries of lower resources.