[VictusIncendia]

I had a few general questions about the electrolysis of water...

1) Could you perform electrolysis on steam? If you didn't need to separate the O2 from the H2 (as in, you would need the H2 and the O2, but they could be mixed together?), could it be done easier if so.
(For example, could you have two electrodes in pure water vapor and send a charge of electricity through it, creating H2 and O2 ?)

2) Is there any way to make it more efficient? Could you make the water vapor conductive with some sort of gaseous electrolyte?

[Donaldson Tan]

http://en.wikipedia.org/wiki/High-temperature_electrolysis

[VictusIncendia]

I read that, but, I suppose my question was a bit vague. If you had a container of pure water vapor, would it be possible to put two electrode within and separate the H2 and the O2? Is the electrolyte necessary? Could you ionize the water vapor into plasma and do it then?

[billnotgatez]

Since all the vapors and gases you are talking about are colorless how would you know which was which. At least when you split liquid water you know which is gas and which is liquid.

[VictusIncendia]

Yes, I know that, but the question remains unanswered. It is a question just to help me understand. Could it be done, if so, how?

[The Tao]

Pure water won't conduct electricity. It has to have salt or any other electrolyte dissolved in it. If you could figure out some way of dissolving a gaseous electrolyte in water vapour, then yes it would work.

[Donaldson Tan]

Methanol-Water mixture has a higher efficiency to produce hydrogen by electrolysis. It can be achieved at much lower voltage. However, the anode product is carbon dioxide, not oxygen.

Anode Reaction:
CH₃OH + H₂O -> CO₂ + 6H⁺ + 6e

Cathode Reaction:
2H⁺ + 2e -> H₂

At standard condition, electolysis of water requires +1.23V, whereas electrolysis of methanol-water requires +0.03V.

[VictusIncendia]

So I've been thinking, and I'm not sure I understand. What exactly is a plasma? It is an ionized gas, yes? From what I understand, if you expose a substance to enough energy (heat, electricity, etc.) you can force the electrons to break off from the nucleus and temporarily make the gas conductive? Is that correct?

[Bakegaku]

So I've been thinking, and I'm not sure I understand. What exactly is a plasma? It is an ionized gas, yes? From what I understand, if you expose a substance to enough energy (heat, electricity, etc.) you can force the electrons to break off from the nucleus and temporarily make the gas conductive? Is that correct?

You're basically right.  A plasma is a gas where the electrons have escaped the orbitals around the nucleus.  This wouldn't help you with electrolysis, though, because both the hydrogen and oxygen would be positive ions in a sea of electrons.  They'd move more-or-less freely through the container while the electrons are recycled.

There's also the issue that it would require extremely high temperatures to do this.

I think your best bet is to use the apparatus shown in the Wikipedia article.

[VictusIncendia]

I'm more curious than anything else, and searching the web didn't give me much. So, I figured I'd ask people who knew a thing or two about chemistry.

The way I understand it, aren't neon signs filled with ionized neon? Why doesn't that require substancial temperature? Is it just a certain amount of energy that is required to pass through the gas? If so, what would it be for water vapor? When you stopped the energy, (a.k.a. cooled it down, or if you can do it with electricity, you stop the current) would it return back to water vapor, or Hydrogen and Oxygen gases? I understand that they would be mixed together, but is this what would happen?

[billnotgatez]

Water is a liquid at room temperature.
Neon is a gas at room temperature
Water is a compound.
Neon is an inert element.

[VictusIncendia]

Ok, so at a high temperature water converts into a plasma state. If you changed it to a lower temperature and applied a high voltage, wouldn't the water become a plasma then as well? Also, when the water returned from plasma back to gas, would it still be together as water molecules? Or would the nucleus' recombine into hydrogen and oxygen gas? If so, what formula could you use to determine the temperature/voltage that would need to be applied to wholly convert water at any specified density? Or is that even available?