There’s just one problem. This is completely impossible.

What this essentially claims is that Genepax has invented a technology that can split water into hydrogen and oxygen consuming less energy than will be produced by re-uniting them.

What they’re claiming is that you can do:

1. Energy1 + 2H2O ⇒ 2H2 + O2

2. Followed by: 2H2 + O2 ⇒ 2H2O + Energy2

3. where Energy2 > Energy1

Only, there’s this thing called “thermodynamics”. You can’t do that. If you could, you could just generate all the worlds energy by splitting water and then recombining it. That would be great – free energy for all! But it doesn’t work. You can’t get more out than you put in.

Source: http://scienceblogs.com/goodmath/2008/06/perpetual_motion_via_fuel_cell.php