This script runs the diode+butler-volmer model that Paul has developed.
It starts with a diode cross sectional area of 1 cm^2 and computes the total surface roughness by accounting for the surface areas of hemispherical catalysts.
The hemispherical area is added to the original cross sectional area.
Surface area can also be added through the inclusion of pores, which are tied to the Pt coverage and diameters.
The depth of these pores must be specified to specify the total area added.