FOR YOUR CONSIDERATION: If your cell has Iron components, they will rust...basic chemistry. The cells will disintegrate with time and the water will have the resulting residue. You could use 316 stainless steel for all metal components in the water, but then your water would contaminate with Hexavalent chromium resulting from the stainless steel. Hexavalent chromium is toxic and you need be concerned about the waste stream in the environment. It would be best to scrap that paper and take an approach used by chemists: use carbon rods or carbon plates for the anode and cathode. Research hydrogen generators in the field of chemistry. You may even find some YouTube videos. Good luck.