Probing heterogeneous electron transfer at an unbiased conductor by scanning electrochemical microscopy in the feedback mode.

ABSTRACT: The theory of the feedback mode of scanning electrochemical microscopy is extended for probing heterogeneous electron transfer at an unbiased conductor. A steady-state SECM diffusion problem with a pair of disk ultramicroelectrodes as a tip and a substrate is solved numerically. The potential of the unbiased substrate is such that the net current flow across the substrate/solution interface is zero. For a reversible substrate reaction, the potential and the corresponding tip current depend on SECM geometries with respective to the tip radius including not only the tip-substrate distance and the substrate radius but also the thickness of the insulating sheath surrounding the tip. A larger feedback current is obtained using a probe with a thinner insulating sheath, enabling identification of

SUBMITTER: Xiong H 

PROVIDER: S-EPMC2535815 | biostudies-literature | 2007 Apr

REPOSITORIES: biostudies-literature