Instructables

Anode and cathode metals? (For electrolysis)

I want to seperate some water to get Hydrogen to play with, so I made a little electrolysis device with a 12v power supply. The only problem is that I have no idea what to use as the anode and cathode! Could I just use screws? Or pennies or something?

hhocells1 year ago
You may use Stainless Steel grade 302 or grade 304 for the “Cathode” (the minus volt wire), but grade 316L is essential for the “Anode” (the plus volt wire).

If you're going to use both in one device, it is important o always make note which is which. Also remember to put a RED wingnut on the bolt connected to the 316L wire, and a BLACK wingnut on the 302/304 wire.
User-Manual_img_207.jpg
djdole1 year ago
The different metals used for cathodes and anodes are not for electrolysis but are for acid batteries (and are usually zinc & copper).
You don't need specific metals for electrolysis, just a metal that conducts electricity, and the two electrodes don't need to be different metals (as they do if you were creating an acid battery).
The important part is having a solvent mixed with the water. (Pure water is non-conductive, so won't work.)

A little chemistry knowledge will help (polarity of hydrogen vs oxygen to identify which electrode is attracting which element).

Also be aware that certain metals will react differently in the electrolysis reaction, combining with either the oxygen or hydrogen to produce new compounds (and in doing so, corroding your electrodes over time).

For example, when I was in 6th grade I used a home-made electrolysis rig to split baking-soda water into 2 parts hydrogen to one part oxygen.
I also used large chunks of copper for my electrodes which meant that on the one polarity, some of the oxygen combined with the copper and created copper-oxide. Later I collected and concentrated the copper-oxide and used that as my solvent in the water. I then by clipping a quarter to the opposite electrode I reversed the reaction and copper-plated the quarter.
Science fun!
I cant remember what we used in general chemistry, but we were calculating columbs and Avogadros number and all that. Save the water that is left over because it has a higher % of "heavy water". I dont know how to make it more pure but its something to play with. :)
NachoMahma5 years ago
. For small batches of home-brew Hydrogen, electrode composition is not that important. Think of them as sacrificial and use something cheap (eg, Copper). . If you plan on making large quantities, then you may want to use something like Carbon, Platinum, &c, as mentioned by others.
Carbon, even pencil leads, for small stuff a mechanical pencil refill pack would do alright. Platinum would be best, I suppose a serious person might use platinum spark plugs as a substitute for buying platinum rods. Silver and gold would probably do well...
westfw5 years ago
Probably the easiest and most inert electrode material you can get easily is a graphite or "carbon rod", like from inside an old-style ("Heavy Duty", but NOT "alkaline") battery. Graphite rods are apparently available as as welding supply (?)
They are used at extremely high amps to cut metal. The arc heats it and then the molten metal is blown out by compressed air. I use them for welding thin sheet (I even made in instuctable about it)

Kiteman5 years ago
The perfect material would be platinum, but otherwise use carbon. I have had plenty of success with pencil-leads (the soft ones conduct better, but snap more easily), so I assume artists' charcoals will be as good.
oops, forgot about carbon, lol, my bad
guyfrom7up5 years ago
out of common materials, I think alluminum is the best
Login258 (author)  guyfrom7up5 years ago
So it doesn't really matter? I figures since stainless steel resists oxidizing (right?), then fewer oxygen bubbles would form and I'd get more hydrogen... Any idea? I'll try out aluminium and let you know how it works!
well, you get the same amount of hydrogen and oxygen, it's just stuff like iron and steel (not sure about stainless steel) will oxidize (rust/corode) really quickly, alluminum still will, just not as fast.
Pro

Get More Out of Instructables

Already have an Account?

close

PDF Downloads
As a Pro member, you will gain access to download any Instructable in the PDF format. You also have the ability to customize your PDF download.

Upgrade to Pro today!