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Author: Subject: More on PbO2 electrodes
testimento
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[*] posted on 26-2-2014 at 16:29


Does anyone have knowledge or experience on lead acetate electroplating PbO2 on graphite?
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UncleJoe1985
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[*] posted on 23-4-2015 at 02:32
use tin as a substrate?


Quote:
Does anyone have knowledge or experience on lead acetate electroplating PbO2 on graphite?


I've made 2 attempts using the easier to obtain acetate.
The results are extremely crude due to not controlling the parameters to be within spec.

1st attempt (simple proof of concept):
coating was extremely flaky and crystal like, with minimal adhesion (could easily wipe it off)

Not surprising since I used no agitation to remove bubbles, room temperature, current density was too high (15mA/cm2), used too much CuSO4 that it seemed to displace the lead from solution, cathode current density too low (why does it recommend it to be 2x the anode current density - to prevent lead from plating out?)

2nd attempt - this time I used a heat gun to heat the solution and provide slight agitation

Result:
No longer flaky and better adhesion after drying, but very spongy instead of solid. I measured the resistance between 2 points 1cm apart and it was ~200 ohms. The graphite rod I used was 10cm x 1cm.

Next: use lower current density, do better job of removing bubbles, use less CuSO4


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UncleJoe1985
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sad.gif posted on 10-5-2015 at 05:52


OMG, I'm an idiot for using CuSO4 :(

That would ruin the plating solution by precipitating the lead out as sulfate! And I used so much CuSO4.

I was wondering what all that white crud at the bottom was. Guess I'll try again with copper acetate.

I think I intuitively understand why copper plates out before lead at the cathode. To explain it in simple physics principles, copper is less reactive than lead, meaning it's harder to ionize. That would mean the Cu ions have a higher electrostatic potential energy. Since the lowest potential energy state is favored, the electrons go to Cu2+.

But what about at the anode? Does oxidation of copper to copper oxides compete with Pb2+ + 2 H2O -> PbO2 + 4 H+ + 4e- (correct me if I'm wrong)

Can anyone point me to the relevant electrode potentials involved?


[Edited on 10-5-2015 by UncleJoe1985]
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Jstuyfzand
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[*] posted on 2-4-2016 at 14:29


What do you all think of this video? Seems pretty good!
https://www.youtube.com/watch?v=bZMWEYiTtso
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Laboratory of Liptakov
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[*] posted on 15-7-2016 at 12:44


Is possible pure PbO2 pressed ? Pressure 12 000 Kg on cm2. And making 10 cm long rod from pure PbO2 ? Diameter 15 mm. How is electric conduction - resistance for PbO2 ? And If is impossible pressed pure PbO2, is possible adding some material for increase solid ? For example, 7% nitrocellulose is confirmed as very good solid - agent. For any fine-powder materials. What using 5% epoxide ? Or some different additivum for increase solidity? Anode will be for prepare NaClO4, of course. Will be nitrocellulose do it problems ? Thanks, ...LL...:cool:
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PHILOU Zrealone
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[*] posted on 17-7-2016 at 04:38


Quote: Originally posted by Laboratory of Liptakov  
Is possible pure PbO2 pressed ? Pressure 12 000 Kg on cm2. And making 10 cm long rod from pure PbO2 ? Diameter 15 mm. How is electric conduction - resistance for PbO2 ? And If is impossible pressed pure PbO2, is possible adding some material for increase solid ? For example, 7% nitrocellulose is confirmed as very good solid - agent. For any fine-powder materials. What using 5% epoxide ? Or some different additivum for increase solidity? Anode will be for prepare NaClO4, of course. Will be nitrocellulose do it problems ? Thanks, ...LL...:cool:

I don't know for the pressed PbO2 stick/rod and properties...

What I know:
Nitrocellulose will be unstable cement because in basic media (what the cell will increase (bleach is already stongly basic for stability and to avoid toxic Cl2, Cl2O, ClO2 gas generation)) it will be hydrolysed into cellulose...thus setting NO3(-) free (good or bad?)...
Now, I don't know how cellulose behaves into a bleach-chlorate-perchlorate cell...but that's easy to find out (by experiment))...will it remain integer or will it be chewed/schreded into pieces?
The following document:
Cellulose solvents and dissolution medias seems to mention that NaOH (7-10%) is able to dissolve cellulose...
You can also make Sweitzers type of solvent or Cellulose xanthan and the precipitate the cellulose into the PbO2 rod...maybe you could work with cellophane another form of polymerized cellulose.

Epoxyde should remain stable into basic media...only into strongly acidic media it would be hydrolysed (but acidic is uncompatible with bleach...so should be OK).





PH Z (PHILOU Zrealone)

"Physic is all what never works; Chemistry is all what stinks and explodes!"-"Life that deadly disease, sexually transmitted."(W.Allen)
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[*] posted on 17-7-2016 at 07:19
PbO2 anode


Thanks, epoxide as binder can be maybe a good material. During next study is clearly , that surface must be perfectly, without micro holes in the surface. Thus, electro deposition on some substrate is necessary process. Unfortunately. Still more thanks, I making it on this. ..LL...:cool:
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yobbo II
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[*] posted on 11-1-2017 at 10:39


Lead dioxide anode for sale 30 dollars + shipping

read all about it here

http://www.amateurpyro.com/forums/topic/1629-making-potassiu...



leadioxide.jpg - 19kB
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ecos
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[*] posted on 12-2-2017 at 05:23


Quote: Originally posted by yobbo II  
Lead dioxide anode for sale 30 dollars + shipping

read all about it here

http://www.amateurpyro.com/forums/topic/1629-making-potassiu...



what is the thickness of the coating and the anode size?
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Ziggy4
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[*] posted on 19-7-2017 at 11:24


I have a thought that should apply to this thread. Upon my own interest in perchlorate synthesis, and reading this thread, and ideas about using inert plastics and solvents like MEK etc. to create a slurry of lead dioxide then coating some metallic substrait with it to use as an anode has me thinking that possibly softening plexiglass with solvent and esssentially rolling it in PbO2, then electroplating more of it onto it electrolytically would work too. I also read Sweede's blog about the subject, and his offset weighted agitator to facilitate degassing of the electrode. He was using surficants to help with that too. How about using an ultrasonic cleaning tank as the plating bath to agetate and mix the entire soln? I found a couple studies on this method and one that uses a probe to deliver the ultrasonic energy past the electrode perpendicularly. The results were very favorable.
http://www.sciencedirect.com/science/article/pii/S0009250914...
And http://www.sonochemistry.info/electro.htm
Hopefully I didn't step out of line here since I am brand new to this forum, and very interested in many topics here. I just couldn't hold back on this possibility though and so I joined in order to make this post and see what you all think.
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