# Which electrodes do not corrode at all?

I had used spare pieces of metal to perform electrolysis. They all had the disadvantage that they corrode when used as anode - and some of the oxides are toxic (copper, chromium).

I've found that carbon, which can be harvested from pencils and old batteries does not corrode contrary to my expectations (I'd expect it to produce $\ce{CO2}$). But soldering on carbon is completely impossible. Also, I need some bigger electrodes.

So are there any metals that do not corrode during electrolysis?

I'm using sodium carbonate as electrolyte.

This highly depends on what you are electrolyzing. When using solutions that are not very acidic, oxide-coated metals sometimes work, like lead-oxide electrodes, that can be harvested from old lead accumulators (attention, lead is toxic, wear lab coat and gloves when working with them. Lead accumulators contain ~20% sulfuric acid, so wear gloves as well and unassemble them in an acid-proof working space)

If you search the web for recipes of perchlorate preparation by electrolysis at home, you will find extensive discussions on the topic of anode materials and making oxidation-resistant electrodes.

Platinum is really hard to corrode, but even it corrodes in some cases.

• I'm starting with just water - but that's enough to turn most electrodes in junk and sometimes very toxic junk. Last piece of metal I used turned the gave the water colour of our profile picture. – Tomáš Zato - Reinstate Monica Jun 25 '14 at 10:12

you do not need to solder a graphite electrode to connect it. It is possible to connect mechanically (screws, wires etc.). It is possible to buy some bigger pieces here: Penta trading

To answer your question: Platinum is really hard to corrode. It is commonly used platinum coated titanium mesh, but it is quite expensive. link: Alibaba

Other than platinum, you can use Gold electrodes, but those are pretty expensive. So unless you use Aqua Regia as electrolyte, the corroding is negligible.

As mentioned before, you can use Platinum and that works great, though it is super expensive. I have used graphite electrodes in the past with either metal fittings or alligator clips. Could that work?

Alternatively, you can do galvanic anodic protection on steel if you are up to it.

• Could you expand what the last idea means and how it works? – Tomáš Zato - Reinstate Monica Oct 2 '15 at 7:42
• Connect a sacrificial anode that will certainly corrode before the one you really care about. This technique is often used on boats and cars. en.wikipedia.org/wiki/Galvanic_anode – John Sep 17 '19 at 1:26