Lead dioxide anode substrates

[Tuatara]

I've been looking into making perchlorates with a lead dioxide anode. What I've found on the net suggests possible problems with graphite as a substrate, being oxisied by the lead dioxde and eventually losing electrical contact. Alternatives seem to be porous ceramics, or Titanium.

I was wondering if silver plated PCB laminate could be used. PCB laminate is an epoxy/glass composite with copper foil glued to the surface. Silver plating would be used as an interface to the lead dioxide, as silver oxide is conductive.

I had also thought of simply using tin/lead/silver solder to cover the copper.

Why PCB laminate? Its clean, cheap, strong, flat, readily available, comes with built in connection point!

Any thoughts, comments, suggestions, rude noises etc would be appreciated, before I go to the effort of trying this.

[Boob Raider]

You will strip the copper right of in no time even if it is silver plated. Even gold is very susceptible to oxidation-chloride damage. If you can .... go to a car battery refurberisher and get the whole setting of the PbO2 plates. You can make a lot of chlorate and then perchlotate with those plates.

[frogfot]

He was asking if it was possible to cover the PCB laminate with lead dioxide...
I think this will produce a porous surface, because of evolution of bubbles. In original they use round electrode that is rotated at high speed to solve this problem. I don't know if it sounds resonable, but maby you can direct a strong stream of electrolyte from a pump onto laminate during electrolysis, like those pumps in aquariums. Maby this will help to remove forming bubbles. Maby having low current dencity will also help, though i don't think it will help alone.

Oh, those lead dioxide electrodes from battery are also porous, they will corrode too fast i have heard..

[vulture]

You can cover your electrodes with lead and then electrolyse it at 3-4V in a 30% H₂SO₄ solution.

[Tuatara]

Now thats an interesting idea Vulture, I've not seen that one before. Would that produce a solid layer of lead dioxide, or a porous one as in a lead-acid battery?

I was planning on removing the bubbles during plating using a combination of a surfactant (I have a bottle of photographic wetting agent - no idea whats in it), with agitation using an aquarium bubbler. Aquarium bubblers are often used to agitate the etch solution when etching PCBs.

[Jumala]

Why covering electrodes with lead?
Simply take sheet lead as electrode. But I think the leadoxide on the electrode will be to thin.

A platinum electrode would be worth to spend some money for.
It don´t need to be solid. Only a covered other metal.
I have searched the net for it with absolute no results.

Perhaps knows someone a source.

[10fingers]

I was going to try this, take the lead dioxide off the plates of a car battery and then pack this into a piece of PVC pipe which has lots of small holes in it. Or, what might be easier is to wrap the lead dioxide with fiberglass cloth.

[Mr Cool]

I wonder how well the structure from inside a catalytic converter would work? 10fingers, you have some experience with these, do you think it could be removed in one piece?
If not, simply dissolve off the metal with aqua regia and plate it onto your metal substrate.

[Guerilla]

You might want to try plating PbO₂ onto something, by electrolysing lead nitrate solution. If you don't have Pb(NO₃ )₂ or nitric acid, you could also use lead acetate made from distilled vinegar and lead metal.. <a href="http://www.geocities.com/CapeCanaveral/Campus/5361/chlorate/leaddiox/plating.html" target="_blank">Here</a> is detailed descriptions of the process.

If you're seriously making respectable amounts of pure chlorate or perchlorate, save yourself and use platinum. It's definately worth of its price! I have just got my Pt-wire and the cell has produced fair amounts of pure white KClO₃ crystals. :)

[Tuatara]

Thanks Guerilla, I've been to that site already, and its a good one. I've got plenty of nitric acid (about 20 l of 68%), 10kg of lead, two dead car batteries. Already made lead nitate, copper nitrate for this process.

I've been all over the net looking at this - found some references to doping the lead dioxide with Fe(III) or Ni to increase surface oxygen activity, anyone know anything about this?

I suppose I could try to get Pt from a catalytic converter, as 10fingers did. Care to post a step by step how-to on Pt extraction, 10fingers?

[10fingers]

I'm not exactly sure how you mean to use a catalytic convertor.
I don't think there is enough platinum on there to make it electrically conductive but I've never tried it.
The catalyst is a fine honeycomb made of aluminum oxide, it comes out in one piece very easily.
To dissolve the platinum, mix 1 part by volume nitric acid 70% to 3 parts hydrochloric acid 31%. Put this in a glass jar and put the catalyst in there, leave it in until it stops bubbling, this only takes a couple of hours. I broke my catalyst up into small pieces but I don't think it was necessary. It breaks rather easily. The finer the pieces the harder it is to filter it out. I would just break it into pieces about 1 in. wide to fit in the jar. Stir the acid often to get fresh acid into the honeycomb of the substrate.
After it stops bubbling, filter out the substrate. Heat this liquid in a coffee pot, it gives off a lot of fumes, until there is just a reddish brown solid left. This is platinum chloride,PtCl4. Heating this to 370*C will liberate the chlorine and leave pure platinum.
Theres a good article at the Rhodium site on how to make platinum and palladium catalysts.

[vurr]

thin layer of silver nitrate forms a metallic silver layer,when heated/reduced directly whith gas flame...(sadly not on lead dioxide)
should work also with platinum compounds on glass.
suitable metal carrier for Pt :Ti.
for PbO2: Ta