KINETICS OF HOMOGENEOUS REACTIONS COUPLED TO HETEROGENEOUS ELECTRON TRANSFER

I. INTRODUCTION Scanning electrochemical microscopy (SECM) has proven a powerful approach for measuring the kinetics of homogeneous reactions coupled to heterogeneous electron transfer. For these investigations, both the tip and the substrate are electrodes, and the tip/substrate configuration essentially functions as a variable-gap ultra-thin-layer cell. The classes of reaction investigated hitherto are primarily those involving irreversible chemical reactions of electrogenerated species (1-6) and chemical reactions sandwiched between successive electron transfers, as in the ECE/DISP scheme (7) (defined in Sec. IV).