# Can I reverse an iron redox reaction with potassium hydroxide and electricity?

For a school project, about clean energy, me and my team are trying to build an iron battery. We are using a piece of iron (anode), potassium hydroxide (electrolyte), carbon electrode (cathode) arranged as shown below:

As to generate electricity from the following chemical reactions:

\begin{align} \ce{Fe + 2 OH- &-> Fe(OH)2 + 2 e-}\tag{1}\\ \ce{3 Fe(OH)2 + 2 OH- &-> Fe3O4 + 4 H2O + 2 e-}\tag{2}\\ \end{align}

Then:

\begin{align} \ce{O2 + 2 H2O + 4 e- &-> 4 OH-}\tag{3}\\ \end{align}

And the overall reaction is:

\begin{align} \ce{3 Fe + 2 O2 &-> Fe3O4}\tag{4}\\ \end{align}

Will this succeed in producing some electricity? And, can the redox reaction be reversed by having an external power source with sufficient voltage like a car battery, then hooking the negative terminal to the iron and the positive terminal to the carbon electrode?

• A redox reaction in a battery can often be reversed by plugging an external power source; this is known as electrolysis. Now what is your reaction? I see two half-reactions, and both are on the same side. What is on the other side? Where do these electrons go? – Ivan Neretin Sep 18 '19 at 5:19
• @IvanNeretin Will the carbon electrode not take in the electrons given off by the iron redox reaction? – user10560552 Sep 18 '19 at 11:38
• Two oxidation half-reactions are shown, but what is the reduction half-reaction? What is the overall redox equation? Where does the iron oxide enter in? This needs some re-working. – Ed V Sep 18 '19 at 11:46
• @user10560552 No. – Ivan Neretin Sep 18 '19 at 12:02
• @IvanNeretin Is this better? – user10560552 Sep 19 '19 at 0:19