Wow! C-ground is in what field? how bout JSwong...so geng one their knowledge? really would like to know.
anyway, as i used to think, electrolysis of water is not so easy becoz it needs some acid to happen, even in small amount, just like in school lab. if acid was added, then the one of the electrodes will have anion build up on it and then become useless eventually.
one elctrode wil produce hydrogen, while another wil produce the anion from the acid and also the oxygen.
extracting both the gasses may be tricky, also storing it under pressure right after extracting.
after seeing C-grounds raw experiment, i figured the solution probly got hot becoz Hydrogen was reacting with Oxigen again to form water. OR the Natrium deposited on the aluminum reacted again with the water to produce NaOH again. When u thorw a piece of pure Natrium into water, u get a sizzling peice of Natrium speeding around while burning and then turning into NaOH. I guess inside the bottle it was happening as soon as it deposited on the aluminum electrodes so you don't see the fire.
Platinum would be an ideal electrode but its not cheap, get from jewelry shop lah haha, platinum is inert, but the only problem is being coated by elements from the solution and then its effectiveness is redueced.
in school experiments, each electrode were covered with a test tube, the solution could move but the gasses produced were isolated. one kind of gas for each electrode. then we removed the test tubes and quickly tested it with a "kayu uji berbara" LOL, POP for hydrogen and the oxygen lights up the other stick.
storing Hydrogen is a bit of a problem becoz somehow, hydrogen can leak out of its tank, corrode some metals n stuff, forgot where i read it. using carbon nanotubes is tricky, i'm not well versed in this at all. being porous and tube like, Hydrogen would just pass through.
water has natural buffer in the form of calcium carbonate and carbonic acid, it also has trace amounts of chlorine even if it is distilled.