Voltammetry on a Nanometer‐sized Electrode in Solution Containing Very Dilute Electroactive Species

Abstract

AbstractA nanometer‐sized Pt electrode is becoming a routine tool in nano‐electrochemistry research, but, the dissolution of Pt in aqueous solution is quite common and the rate of the dissolution of Pt is related to the current density on the electrode. Measurement on a nanometer‐sized Pt electrode in solution containing very dilute electroactive species can effectively decrease the current on the electrode and thus decrease the extent of the dissolution of Pt electrode. So far, a commercial potentiostat which has a peak‐peak noise of less than 10 fA is not common. In this paper, a homemade potentiostat, which has a peak‐peak noise of less than 5 fA, has been made. By using the instrument, voltammograms with a limiting current of less than 20 fA can be obtained on a nanometer‐sized electrode in solution containing micro molar ferrocenemethanol. Our results show that the standard rate constant of the oxidation of ferrocenemethanol measured in micro molar ferrocenemethanol solution is a little greater than that measured in mili molar ferrocenemethanol solution, which indicates that kinetic parameter may be affected by the amount of electroactive molecules being measured.