Derive equation 1 to equation 2

...equation 1

i = nFAC*/d ...equation 2

A diffusion-limited steady-state current for a two-electrode cell

Assumptions:

- Electrode surfaces are parallel and opposite to each other and are separated by a distance, d.

- A redox reaction, O + e = R

- Only the species O is present in the solution at the start of the experiment at concentration C*

- D_O = D_R = D.

- The bottom electrode is held at a potential (EbE 0) where O is reduced and the top electrode is held at a potential (EtE 0) where R is oxidized.

- The solution contains excess supporting electrolytes and is not being stirred.

- k is the rate constant

tc(x,t)=Dx22c(x,t)+kchemC(x,t)