Generating Hydrogen... Without Batteries





Introduction: Generating Hydrogen... Without Batteries

Generate hydrogen quickly and easily without those costly 6V batteries! Using H20 Electrolysis, generate hydrogen (and chlorine gas) with only water! The setup will take only 5 to 10 minutes, and can be safely left running overnight. Generate bottles of hydrogen with ease!

This Instructable is not only my first... it is also for the Science Fair contest.


Step 1: The Parts

You only need four things:

  • A wall transformer ($4.77), which is available here on 12 Volt Transformer]

  • Salt... optional

You can complete this project for as little as $4.77 or as much as $29.87.

Step 2: What to Do

First, put the water in a bowl and mix in salt (optional). The salt will simply increase the speed of the reaction.
Next, cut the plug off of the wall transformer. Next, install a fuse to prevent the transformer from breaking in the event of a short. A good fuse is available here on In addition, you can screw on a switch like this. Separate and strip the two wires (you can get a wire stripper here: ). Plug the transformer in and submerge both leads in water. To enhance production, you can use pencil graphite by sharpening both ends of a pencil.
One should be rapidly generating bubbles, which are full of hydrogen. Once you know this works, go ahead and tape the lead that does not generate bubbles to the side of the container (still under water). Next, take a test tube or bottle filled with water and while keeping the bottle/tube filled, submerge the open end under water. This prevents air from entering. Thread the wire that generates bubbles into the tube.

Step 3: Other Capturing Ideas

Now that you can capture hydrogen, you can also try to capture chlorine gas bubbles (basically oxygen). Simply place a separate bottle over the other lead. This gas is generated much more slowly.

If you like explosions, you have two options:
Remove the bottle of hydrogen and stick a match inside. BOOM!
Use one bottle to capture both gases. This creates the perfect mixture for an explosion. Be careful!

Please not that using salt produces chlorine. Because chlorine is heavier than air, it will fall to the ground. Chlorine is a very dangerous chemical that can suffocate you. To prevent a catastrophe, use another bottle/test tube to capture it.
Another alternate is to use baking soda instead of salt. This will produce oxygen instead of chlorine.

Step 4: Holding the Bottles

Always hold the bottles opening-down (as if you were pouring out water). Remember, hydrogen is much lighter than air... it floats up. It does not fall down.

I hope you enjoyed this Instructable. While the concept is not new, using a wall transformer is a unique and inexpensive solution. This is a fun experiment... but as with all explosions, be careful!

Step 5: Explanation

WARNING: Science Content:
When current from the wall transformer passes through the water, the water molecules are split into hydrogen and hydroxide ions. The lead with bubbles, which produces Hydrogen, can be explained through the following equation:*
2H2O(l) + 2e− → H2(g) + 2OH−(aq)
The other lead, which produces nothing unless a better electrode, like graphite or platinum is used, can produce hydroxide. The formation of hydroxide ions then turn into oxygen (or chlorine if salt water is used). The following equation* defines the reaction:
2H2O(l) → O2(g) + 4H+(aq) + 4e−
The overall reaction is defined in the following equation:
2H2O(l) → 2H2(g) + O2(g)

NOTE: equations are from here.



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    118 Discussions

    does this create less power than is needed to generate it. Like other hydrogen generators

    You said that it was a single "molecule of hydrogen," but all elements are atoms, unless bonded. A molecule is a covalently bonded group of atoms.

    2 replies

    Actually most hydrogen found in nature is exists as H2 like O2, N2, I2, F2, Cl2 and Br2. Or as I learned the 'diatomic' molecules:

    HonI FiCl Brs (pronounced 'honey fickle burrs') - Thanks Coach Pauley...26 years later I still remember!

    So how much hydrogen is in the average bucket of water?

    O and chlorine is NOT the same as oxygen, it is toxic and does not help explosions, DO NOT BREATHE IN CHLORINE!!!!! it WILL fill your lungs and starve you of oxygen. The good thing about it is that it is heavier than air so this is hard to do.

    14 replies

    Mixed Hydrogen and Chlorine will spontaneously explode without ignition. Breatheing chlorine or hydrogen chloride will surely cause a life threatening trouble breatheing and instant loss of consciousness. Carelessness almost absolutely guarantees that this will happen. How about using baking soda instead of salt? Using copper wire is OK, it may turn the saltwater green by making copper chloride. The positive wire just dissolves slowly. You can protect the transformer from shorting wires with a 1 amp fuse, or a cheaper small 10 ohm resistor (brown black black). If you do short it, then the fuse or resistor burns up instead.

    When you say spontaneously explode, do you mean it can happen at any moment? I thought you needed a match...

    H and O needs a match. H and CL just goes boom whenever it feels like it.

    Hmmm.... I just tried setting off both with a flame and nothing happened...

    Hydrogen and Chlorine don't spontaneously react, they need a near UV photon to initiate under otherwise presumably safe conditions at STP.. Its pretty dang close to spontaneous though in practise, in all cases, you should separate the gasses whatever they be if you're dealing with much more than test-tube fulls.. BTW, the chemistry outlined isn't exactly correct.. Its a redox reaction, not an acid base thing..

    As with all projects of this nature, it can be dangerous. Common sense can be the best protective action... My water turned green, but that doesn't really matter

    In the event of this happening shouldnt you stand on your head and exhale alot so the chlorine sinks back down your throat? Just a theory...