Electrochemistry at Nanometer-Scaled Electrodes

Advances in the fabrication of nanometer-scaled electrodes during the past decade have created a number of exciting opportunities in both physical chemistry and analytical measurements. This article describes how Pt electrodes of nanometer dimensions are synthesized and characterized in a chemical laboratory. A few examples of their applications in fundamental studies of electron-transfer mechanisms and in analytical chemistry are presented. Examples include investigations of the dependence of electron-transfer kinetics and molecular diffusion on interfacial electric fields and electrochemical detection of very small quantities of a redox-active species (zeptomole detection). The concept of comparing the electrode size to the length scales of various microscopic structures (e.g., the double layer) and chemical steps that define electrochemical reactions is emphasized. This approach allows students to understand why new phenomena appear as the electrode size is reduced to the nanometer scale. A brief overview of literature describing electrochemical experimentation with nanometer-scaled electrodes is also included.