Simulation of Fick's Second Law for Spatially Variant Diffusion Coefficients

摘要

Simulations of cyclic voltammograms for a system with a spatially variant diffusion profile are presented. An expanded version of Fick's Second Law is used to account for a diffusion coefficient that varies with x, distance normal to the electrode surface. Parameters to define the slope and magnitude of a linearly graded diffusion profile are described. A one dimensional explicit finite difference simulation method is used and parameters are made to be dimensionless. The simulation is vetted by comparison with Nicholson and Shain simulations and determination of the resolution limits. Morphological changes in cyclic voltammograms are observed that indicate an approach to steady state diffusion.