Science Buddies: "Ask an Expert"

Hello,

For my project last year, I constructed a proton exchange membrane (PEM) fuel cell by splitting water into hydrogen and oxygen with a battery, then allowing them to recombine in the precense of platinum catalyst. (I used this site as a guide: http://sci-toys.com/scitoys/scitoys/ech ... _cell.html ) However, fuel cells don't work exactly like this. The hydrogen is split into protons and electrons at the anode (platinum catalyzes this reaction, right?). The protons travel through the proton exchange membrane and the electrons travel through an external circuit. Then, the protons and electrons recombine with oxygen at the cathode to form water.

Is there any way to alter my proceedure to include the step of splitting hydrogen and having the electrons go through the external circuit?

Thank you,
candy4me

I don't quite understand your question, I'm afraid. The web site you point to isn't about a PEM cell at all, but rather about a simple way to demonstrate platinum catalysis of a H2 + 2O2 = 2 H2O reaction.

A PEM fuel cell (http://en.wikipedia.org/wiki/Proton_exc ... _fuel_cell) is a way to construct a fuel cell so you can efficiently deliver H2 and O2 to a catalyzed reaction. It necessarily has a polymer layer that is specially designed to direct the flow of the fuels being used to the catalyst.

Could you clarify what kind of fuel cell you actually built? And what your question is about it?

I guess I said that incorrectly--I followed the website's instructions and so did not construct a PEM fuel cell but just the demonstration of putting hydrogen and oxygen back together. What I am trying to find out how to do is construct a PEM fuel cell that includes the proton exchange membrane and the step of splitting hydrogen into protons and electrons.