Hang on, I don't quite get this.
Normally you have the two electrodes in seperate "collection chamber" so that one collects the hydrogen to be drawn off and the other the oxygen. Looking at that article, and video, there is no seperation so the "atmosphere" in the vessel is surely a collection of H and O? Admitedly that can be recombined with some energy output (as well water.)
But they are talking hydrogen production for fuel cells here. I am missing, or misunderstanding, something here? A nice schematic would help!