[Oseania]

Hello,

In one project I have thin Pt sheet which is deposited on top of conductive carbon sheet (carbon black). I was wondering is it possible to dissolve the solid carbon using KOH or NaOH. I understand that these don't affect the Pt-layer.

[Arkcon]

I don't believe there's a simple, easy to use solvent for carbon.  Usually, carbon is removed with very esoteric reagents at high temperatures and pressures, but your Pt film won't survive that.

[Hunter2]

The question is how the carbon was fixed to the platinum I would use HNO₃ and a strong Ultra sonic bath. I wild dissolve the carbon but weaken the bonding to the platinum. probably the Hydroxide also will work.

[Oseania]

Thank you.

What if the Pt coating was on top of Nickel. Would there be any method of stripping the Nickel out but leaving the Pt?

[Hunter2]

Nickel is  soluble in any acid.

[Enthalpy]

If you have thin films and deposition processes, maybe you access a plasma etch machine? Then carbon-to platinum selectivity must be possible, with hydrogen if the machine permits it, maybe with oxygen, or more subtle species.

If you deposit on silicon, some etchants are known, as simple as KOH. This can be advantageous, for instance to leave some patterns of silicon to support the Pt film.

[ScottF]

The plasma etch machine in my lab was new last year, I think it only cost about 6 grand.  Here is a link to the one I use.  http://www.plasmaetch.com/pe-25-plasma-cleaner.php  We use it with oxygen and I usually let it go for about 6 minutes.  Hope that helps!

[Enthalpy]

Maybe an alternative - or maybe not. Worth a trial, since the hardware is rather common.

Nanosecond and picosecond pulsed lasers are used to clean dirt away from stones, among many uses. In the infrared (most lasers are IR) carbon absorbs much while platinum reflects efficiently, so with limited luck, evaporation will stop at the metal layer.

One trick with short pulses is that heat doesn't diffuse deeply, so it will spare your Pt layer. The other trick is that heat serves then to evaporate the dirt without being lost to the depth, and leaves the material nearly untouched. Used in mechanical production to make the cuts cleaner.