TY - JOUR

T1 - The steady-state current for a ring-like microelectrode under non-diffusion-controlled conditions

AU - Phillips, Christopher G.

AU - Stone, H. A.

N1 - Funding Information:
I'he authors are grateful to Dr D. O'Hare for suggesting ::he problem to them. They also gratefully acknowledge financial support, for CGP from a Wellcome Trust Mathematical Biology Research Fellowship, and for HAS from NSF-Presidential Young Investigator Award CTS-8957043.

PY - 1995/10/31

Y1 - 1995/10/31

N2 - The steady-state current for a 'ring-like' microelectrode is considered, when the electrode reaction rate is not sufficiently large that the diffusion of the electroactive species is the rate-limiting transport process. This régime is particularly relevant for micro-ring electrodes (which the present formulation includes), because the criterion for diffusion-limited transport is much more stringent for a thin micro-ring electrode than for a micro-disc of comparable size. First an approximate solution is presented for the steady-state current for a ring-like microelectrode, valid for any value of the electrode reaction rate provided the ring is thin. For the special case of a thin, plane-mounted micro-ring electrode, numerical results are given and the surface current density distribution is shown. In this case the total current is found to be in close agreement with a semi-empirical approximation due to A. Szabo (J. Phys. Chem., 91 (1987) 3108). A micro-ring electrode with an arbitrary ratio of inner to outer radius is then considered, and the steady-state current is calculated numerically as a function of the electrode reaction rate for a range of geometries, extending from a complete disc to a thin ring.

AB - The steady-state current for a 'ring-like' microelectrode is considered, when the electrode reaction rate is not sufficiently large that the diffusion of the electroactive species is the rate-limiting transport process. This régime is particularly relevant for micro-ring electrodes (which the present formulation includes), because the criterion for diffusion-limited transport is much more stringent for a thin micro-ring electrode than for a micro-disc of comparable size. First an approximate solution is presented for the steady-state current for a ring-like microelectrode, valid for any value of the electrode reaction rate provided the ring is thin. For the special case of a thin, plane-mounted micro-ring electrode, numerical results are given and the surface current density distribution is shown. In this case the total current is found to be in close agreement with a semi-empirical approximation due to A. Szabo (J. Phys. Chem., 91 (1987) 3108). A micro-ring electrode with an arbitrary ratio of inner to outer radius is then considered, and the steady-state current is calculated numerically as a function of the electrode reaction rate for a range of geometries, extending from a complete disc to a thin ring.

KW - Ring-like microelectrode

KW - Steady-state current

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U2 - 10.1016/0022-0728(95)04021-F

DO - 10.1016/0022-0728(95)04021-F

M3 - Article

AN - SCOPUS:0001101261

SN - 0022-0728

VL - 396

SP - 277

EP - 283

JO - Journal of Electroanalytical Chemistry

JF - Journal of Electroanalytical Chemistry

IS - 1-2

ER -