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Electrolysis Materials Answered

I have been looking at electrolysis a lot, and recently made one, but because I used copper wire it corroded straight away.  I have been looking at alternatives and titanium sticks out to me.  Currently cheap, $10 for 16 feet, and the conductivity is fairly good along with the corrosion resistance (high).  However, I haven't been able to find very much of anything stating that titanium works or doesn't.  Does anybody have any input, thanks!

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Jack A Lopez

4 years ago

Here's something on the subject of titanium as an anode in aqueous electrolysis:

(Spoiler altert: bare titanium is NOT a good anode material, because it passivates.)

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Cody HeiserJack A Lopez

Reply 4 years ago

Thanks, that is very helpful, glad I didn't waste money on titanium then find this out! What material would you recommend for the anode? I've heard some mixed thoughts on stainless steel (with chlorine gas). Thanks again, Cody.

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Jack A LopezCody Heiser

Reply 4 years ago

So you want to make chlorine, by oxidizing chloride ions to chlorine gas,

2 Cl<sup>-</sup> = Cl<sub>2</sub> + 2 e<sup>-</sup>

erm... right?

I think I'd try graphite, or some kind of conductive carbon, like a carbon rod from a zinc-carbon battery.

Also for electrolysis experiments, I like to use constant current, meaning using a regulator circuit that actually watches the current and keeps it constant. I have a few reasons why I like constant current.

The first reason is I think limiting the current density to the electrodes will help them last longer, no matter what they're made of.

The second reason is it makes the math easier. With constant current I am pushing known quantities of electrons through the cell, per unit time.

Third, I happen to have one of those bench type power supplies that can regulate voltage or current, so constant current is something easy to do, with the equipment I have.

I think for making chlorine it helps to keep the pH at the anode low, because chlorine gas will react with hydroxide OH<sup>-</sup> ions to make hypochlorite ClO<sup>-</sup>, and also chlorate, ClO3<sup>-</sup>, at higher temperatures.

Unless of course you're trying to make hypochlorite, or chlorate. The Wikipedia article on hypochlorite and chlorate can explain more on how that works.

I remember a while back, someone here on Instructables made an cell for electrolysis of brine with a conductive separator (made out of Knox(r) brand gelatin, I think) so he could prevent the anode and cathode electrolytes from mixing, here,

https://www.instructables.com/id/Make-Lye-From-Salt...

A piece of wet string, or paper, might also work as a cell separator, although the electrical resistance of long skinny things tends to be high, thus wasting electrical energy. So a trick like that won't work on an industrial scale, but it might work in the lab, or garage.

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Cody HeiserJack A Lopez

Reply 4 years ago

Thank you so much for the help! I have been looking breifly and have been unable to find anything like this! This is very helpful so thanks again!

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Downunder35mCody Heiser

Reply 4 years ago

Again: If you would specify what exactly you are trying it would be much easiert to help ;)

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Downunder35mCody Heiser

Reply 4 years ago

For HHO 316 or 317 grade stainless will be close to perfect at the best value for money.

AL-6XN stainless can be used if you have high levels of chloride, like when using cheap salt in the water to assist conductivity.

Instead of salt a few drops of hydrochloric acid gets a better conductivity and less problems in terms of chloride or chlorate contamination due to the electrolysis of the salt.
Round cells made from thin pipes are a good way to improve on the efficiency, but it can be hard to find the right diameters as scrap.

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Downunder35m

4 years ago

I would certainy help to know what you are trying to do.

Anode and Cathode materials hugely depend on what you have as the electrolyte.

For basic HHO things marine grade stainless steel is a good choice.

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Cody HeiserDownunder35m

Reply 4 years ago

I would most likely be using baking soda and water. Thanks for the reply!