Effect of Polishing with Different Size Abrasives on the Current Response at a Rotating Disk Electrode

摘要

In this research group as well as other substantial emphasis has been placed on the surface preparation of rotating disk electrodes. This emphasis exists because the transition to turbulent flow can occur at much lower rotation speeds on an less perfectly polished rotating disk. We thought it worthwhile to study systematically the effect of polishing procedures on the Levich response of a rotating disk electrode. In the rotation speed range 400-8100 rpm, no significant effect on the Levich responses was observed for either gold or platinum RDE's polished with abrasives in the size range 0.5-14 m. The maximum Reynolds number reached for the RDE's used in this study, radius approximately 0.4 cm, was about 1.4 x 10, and was more than an order of magnitude lower than the critical value for onset of turbulence, 2.2 x 10 to the 4th power. An electrode whose surface appearance is reflective and relatively scratch-free is more than sufficient to obtain ideal Levich behavior. Time-consuming and tedious polishing with submicrometer-sized abrasives is unnecessary. (Author)