I know the concentration of a substrate in a water solution and I want to calculate the diffusion limiting current density for an electrode that reacts with that substrate. What are the steps to calculate that? I think I need to use Fick's law but I am not sure how to calculate dφ/dx. I assume I will get a mass transport moles/m3*second rate from Fick's law and then I can convert that to electrons and then Electrons/second to find the amperes. Can you advise please on the steps to follow?