Thanks for all your replies guys.
I suppose I need to be more specific.
I have developed a cheap method for stored energy in the form of oxygen and hydrogen from water without the need of a dc generator to split them. I understand thermodynamics so if you would please reread my original post as vague as it is you would see my problem isn't the energy factors but separating the two gases:). I am trying to use the most energy/cost efficient and safe process for separating the gases to increase my yield of the stored energy. The process does not allow for me to keep the gases separate . Also production is important so I am not sure that a membrane would work. I am starting to lean towards a distillation tower but I don't exactly have the liquid gases required to cool them to be condensed, also I think this method requires allot of energy that would defeat the purpose of my project.
I'm not using thermal, the process runs at room temperature.
My roadblock is simply separating the two gases from one another.
Could the mercury gas be condensed at more manageable temps then what I would need for a distillation tower for the oxygen or hydrogen? Maybe mercury isn't the way for me to go, but maybe creating a different oxide?? Maybe iron or something more manageable? I don't know, my lack of chemistry knowledge really has me stumped.