RDE-4 — Rotating Disc Electrode System

The RDE-4 is a rotating disc electrode system for hydrodynamic voltammetry (Levich / Koutecký-Levich analysis, ORR/OER/HER electrocatalysis, diffusion coefficient determination). Electrode rotation speed is set in the ROTATION section of the front panel with the LOCAL / SET / REMOTE switch: in SET the speed is chosen with the RPM knob, in LOCAL the electrode rotates at that speed, and in REMOTE the speed is controlled by a 0 – 10 V analog signal from the potentiostat (0 – 10,000 RPM). The set speed is also available to external instruments on a 0 – 10 V analog output.

The PURGE section manages the duration of gas flow through the cell with a timer: the time is set in SET, in LOCAL gas flows during the countdown and can be started or stopped at any moment by pressing the PURGE TIME knob; in REMOTE the potentiostat's logic signal switches the purge on and off. The front-panel flow meter (GAS FLOW CONTROL) adjusts the stirring gas rate; when the purge is off, the 'Gas Blanket Line' keeps a blanket gas flowing over the cell to minimize contact between the sample and air. The gas inlet is a 6 mm push-fit tube connection; the supply pressure must not exceed 5 psi (0.34 atm).

Cell leads pass through the tunnel at the rear of the instrument to avoid cable clutter at the front; the working electrode and GND inputs are on the front panel, while the counter and reference electrodes are mounted in the ports of the cell lid. The active level (0/1) of the rear-panel ROTATE and PURGE logic inputs and the audible alert can be adapted from instrument to instrument in the setup menu, so synchronized experiments can be set up with Bio-Logic, Entek and other brands of potentiostats.