Scanning Electrochemical Microscopy induced transfer

The time range of the electrochemical measurements has been decreased considerably by using more powerful -> potentiostats, circuitry, -> microelectrodes, etc. by pulse techniques, fast -> cyclic voltammetry, -> scanning electrochemical microscopy the 10-6-10-1° s range has become available [iv,v]. The electrochemical techniques have been combined with spectroscopic ones (see -> spectroelectrochemistry) which have successfully been applied for relaxation studies [vi]. For the study of the rate of heterogeneous -> electron transfer processes the ILIT (Indirect Laser Induced Temperature) method has been developed [vi]. It applies a small temperature perturbation, e.g., of 5 K, and the change of the open-circuit potential is followed during the relaxation period. By this method a response function of the order of 1-10 ns has been achieved. 

A.L. Barker, J.V. Macpherson, C.J. Slevin, and P.R. Unwin (1998). Scanning electrochemical microscopy (Seem) as a probe of transfer processes in 2-phase systems— theory and experimental applications of secm-induced transfer with arbitrary partition-coefficients, diffusion-coefficients, and interfacial kinetics. J. Phys. Chem. B 102, 1586-1598. 

This chapter is concerned with the study of interfacial processes and reactions that occur essentially at electrically insulating interfaces, where the role of the SECM tip is often to induce and monitor the reaction of interest. The work herein is an update of Chapter 12 Probing reactions at solid/liquid interfaces of the first edition of Scanning Electrochemical Microscopy [4] and highlights how the basic principles of the SECM-induced transfer (SECMIT) mode (or equilibrium perturbation mode) and related techniques— notably (multi-) potential step transient methods—can be applied to a wide variety of interfaces where flux measurements have traditionally been difficult. 

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