elementcollector1 - 17-6-2012 at 14:56
I am trying to make Na- and KOH through the one-cell electrolysis of their carbonates (for Na, the bicarbonate). Is there an anode material that is
resistant/immune to carbon dioxide and alkali hydroxides?
elementcollector1 - 17-6-2012 at 20:06
Never mind, nickel appears to work. Does not have an amphoteric oxide, metal, or hydroxide. Excellent!
RadioTrefoil - 18-7-2012 at 00:10
Graphite's the way to go. Nickel will corrode over time.
plante1999 - 18-7-2012 at 02:19
platinum.
woelen - 18-7-2012 at 03:17
Nickel is good enough if you are electrolysing hydroxide solutions. Even plain copper wire works great with solutions of NaOH and makes O2 at the
anode without the copper dissolving.
blogfast25 - 18-7-2012 at 04:22
Carbon is attacked by strong alkali. Platinum is overkill.
plante1999 - 18-7-2012 at 04:25
If you don't want to overkill, iron can do the job, but it will add some impurity.
hyfalcon - 18-7-2012 at 06:38
I've got some grade 330 stainless steel that I'm trying to figure out how best to use in a cell myself. With it's high nickel content this might be a
good experiment.
plante1999 - 18-7-2012 at 07:17
Never use SS steel as an anode in alkaline electrolyte, the chromium will leach out as chromate and the resultant nickel-iron alloy is like sponge and
will make flocculent hydroxide, all this happening pretty fast. I don't even explain in acid sol., SS is very unuseful as an anode.
kristofvagyok - 18-7-2012 at 08:19
I have never tried it, but a friend suggested Ti anode, what would be pretty cheap and it is highly resistant.
Or use Hg?
phlogiston - 18-7-2012 at 14:02
I think Ti will passivate. Stay away from Hg if you value your grey cells. Only resort to it if it is the only thing in the world that will do the
job. Use Nickel or Platinum.
vmelkon - 19-7-2012 at 04:13
A nice graphite rod from a D cell non alkaline battery is probably the cheapest solution.
You can try silicon if you want but the conductivity is very low.
As for Hg, I've always been curious about that one as an anode. I have only used it as a cathode.