[SinAnu]

In my school we are developing and investigating the process of generating electricity by means of an hydrogen fuel cell.
We have started with an aqueous solution of NaCl and connect it to a 12 volt generator. Then, we waited for 3-4 minutes and disconnected it from the generator and connected to a voltmeter. The voltage was near 1 volt. How could we increase this voltage? We used copper electrodes, but we know the platinum would be a better catalyst, but it is being difficult to buy it here in Azores. What are your tips, suggestions, to increase this voltage?

Also, during the process it appeared a greenish substance which I think it is Cu⁺ from the oxidation of the cooper. Isn't it?
If you could post some links for more information about this, it would be also be great help.

I appreciate your help. Thanks! 

[billnotgatez]

You might find some ideas here.
I think you can use carbon rods from inside old dry cells

http://sci-toys.com/scitoys/scitoys/echem/echem.html

http://www.funsci.com/fun3_en/electro/electro.htm

Could the green color be chlorine as well?