Solar Electrolytic Cell

Hello, everyone! This is actually my first Instructable for the Chemical Reactions challenge, but I also want to help those looking for ways to use green energy or who are just looking for a fun project. Today I'll be showing you how to make a Solar Electrolytic Cell that splits water into hydrogen and oxygen. Good luck and enjoy!!

Step 1 Materials

Here's what you'll need for this project:

- Solar Cell (preferably 1.2V or higher; you can probably get one off Amazon for $7; the one I'm using is a 6V I got from Radioshack for $16)
- Cup or container (sorry that mine is so dark, it was all that I had)
- Wire
- Capacitor (optional; you can get one by harvesting a disposable camera)
- Soldering Iron & Solder (optional; makes things WAY easier though)
- Tape

Comments

[GASSYPOOTS]

can i haz AA versionz?

[pabs129]

please reply me soon.i m in a hurry to make a hydrogen related project

[pabs129]

how can i store the liberated hydrogen separately in a container without oxygen

[kretzlord]

A nice, scalable, concept. Do you have any applications for this yet? Also, i'm not an expert on electrolysis, but i'm fairly certain that for the water to recombine, you need to add energy (ie heat), or have a catalyst (as seen in hydrogen cars).

*fun idea* adjust your water container to accept a balloon on the top so you can fill it with a perfect molar ratio of H and O. When the balloon fills up, tie the end, then tape on a piece of cannon fuse. Light. Release. Plug your ears. and only do that under competent adult supervision....

[tzq33tdq]

i heard platnium wire works to make the elecricity. im making something like this but it will have a switch for input or output. or a valve that goes to a torch/hydrogen engine/genorator that runs on compressed air/hydrogen/any compressed gas.

[ironsmiter]

Once the gases split, you don't need ANY electricity to keep them from reverting to water. So the capacitor is a frivolous add on for this circuit.

The 2 H2O(l)→2 H2(g)+O2(g) reaction , when reversed, produces HEAT energy aka it's flaming gasses! No measurable electricity produced.
Although the chemical reaction SEEMS simple enough... there are actually a few half-reactions involved, that prevent a true two-way reaction. That's why you need flame/spark to reverse the equation. It is just for the sake of simplicity and brevity, that we write the equation the way we do.


Also note, PURE water(distilled, de-ionized) will NOT work, especially at the low voltages produced though consumer grade solar-voltaic cells.

Final experimenters note.
Never EVER run this with the cap on.
When the water being split is in an enclosed container, what you have is a BOMB! :-)
Sure, that can be fun in and of itself, but you need to treat it as such.


To help stave off arguments... here's the half-reactions ACTUALLY involved(well, ONE of them, as best explained by http://en.wikipedia.org/wiki/Electrolysis_of_water)
2 H2O(l) → O2(g) + 4 H+(aq) + 4e−
2 H+(aq) + 2e− → H2(g)

[techno guy]

If running it with a cap on makes it a bomb, then when it explodes does it explode with fire or does the bottle just rupture from the pressure?

[ironsmiter]

possibly BOTH.

initially, you would just have the gasses building up pressure, till the vessel ruptured.
The severity of the rupture is directly proportional to the container.
Small film canister, with the press on lid, not much worry. after a few psi, it'll just go "pop" and the lid will partially come off. Screw-on-lids, glass jars, metal containers... all a fair bit worse, when the give up their structural integrity.

then you have a concentrated ball of highly flammable gas, and pure oxygen, waiting for the least little spark, heat, or flame, to turn into a proper explosion.
This danger increases, the larger your container, and the greater pressure.
these qualities allow MORE gas to build up before the potential explosion.
More gas = bigger boom = more dangerous :-)