Diffusion-Limited Currents to Nanoparticles of Various Shapes Supported on an Electrode; Spheres, Hemispheres, and Distorted Spheres and Hemispheres

J. Phys. Chem. C, 111 (49), 18049 -18054, 2007. 10.1021/jp076593i S1932-7447(07)06593-4
Web Release Date: November 10, 2007

Diffusion-Limited Currents to Nanoparticles of Various Shapes Supported on an Electrode; Spheres, Hemispheres, and Distorted Spheres and Hemispheres

Ian Streeter and Richard G. Compton*

Physical and Theoretical Chemistry Laboratory, Oxford University, South Parks Road, Oxford, OX1 3QZ United Kingdom

Received: August 16, 2007

In Final Form: September 20, 2007

Abstract:

The finite difference method is used to simulate the current at a spherical nanoparticle sitting upon a planar electrode, assuming electrolysis occurs only at the nanoparticle surface. The accuracy of the simulation technique is confirmed by using the same approach to simulate a hemispherical electrode. Nanoparticles with the geometry of a distorted sphere or hemisphere are also considered. Equations are given for the corresponding mass-transport-limiting current. For the spherical nanoparticle, this expression is i_lim = -8.71nFDr_s[A]_bulk, where D is the diffusion coefficient, r_s is the radius of the particle, [A]_bulk is the bulk concentration of the electroactive species, and n is the number of electrons transferred.

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