Sciencemadness Discussion Board

Voltage of Chlorate Cell important?

Amoled - 20-9-2018 at 12:56

Is it important what Voltage I choose?
I thinked about getting a Power Supply with 12V and 60A, would the 12V be too much for the production of Chlorate?
The 60A shouldn't be a Problem, as I have a big enough Platin-Anode.

MrHomeScientist - 20-9-2018 at 13:13

I believe generally you don't want to go above 5 or 6 volts, but others may have more experience or info.

macckone - 20-9-2018 at 19:05

I usually run 5 volts with up to 20 amps but I usually limit it to avoid too much heat and wear on my MMO mesh.
My power supply is derived from a computer power supply.
I use MMO for chlorate and limit the amperage to reduce wear as noted.

For perchlorate, lead oxide is the best choice.

Amoled - 20-9-2018 at 20:35

Quote: Originally posted by macckone  
I usually run 5 volts with up to 20 amps but I usually limit it to avoid too much heat and wear on my MMO mesh.
My power supply is derived from a computer power supply.
I use MMO for chlorate and limit the amperage to reduce wear as noted.

For perchlorate, lead oxide is the best choice.


So MMO would also be easy to get, also it wouldn't be a huge Price difference to Platin, while I haven't Seen Lead Oxides ones.
With Platin I have read that it's Perfect and nearly not corrode, and other sources said that I definetly shouldn't be using Platin at it would Wear off instantly....
What should I believe? I thought Platin-Eldctrodes would be one of the best

greenlight - 20-9-2018 at 23:16

I use a cell voltage similar to macckone, 5 volt 20 amp computer power supply with MMO anode and Ti cathode.
Is a bit wearing on the electrodes but makes a heap of chlrate quickly.

markx - 21-9-2018 at 01:08

Quote: Originally posted by Amoled  
Is it important what Voltage I choose?
I thinked about getting a Power Supply with 12V and 60A, would the 12V be too much for the production of Chlorate?
The 60A shouldn't be a Problem, as I have a big enough Platin-Anode.


12V is overkill for electrolysis/synthesis. Do not make life complicated for yourself and get a 5V 60A power supply (preferentially with an option to regulate the output voltage at least to some degree).
The power supply just needs to output enough voltage to overcome the summary electrochemical potential of the cell. To put simply a certain voltage is required to make certain electrochemical reactions possible in a cell. In a generic chlorate cell this voltage is in the range of about 3,5V. Mostly everything above that voltage shall translate into resistive voltage drops across the elements of the cell circuit and be released as heat.
To drive a chlorate cell from a 12V power supply would in the first hand cause excessive heat evolution in the system.
Secondly the amperage would be driven sky high as there is little passive resistance in a properly constructed cell circuit.
Thirdly the electrodes would be polarized to a potential range where damage occurs to the anode.

In essence a chlorate cell can be driven from a 12V power supply and all of the abovementioned issues can be overcome to some degree with appropriate countermeasures of cell design. But a good insight into the physics and chemistry of the system is required for that.
And when one has that insight, then the realization that the simplest path to optimisation of the system is to lower the voltage becomes really apparent :D

Amoled - 21-9-2018 at 01:44

Thank you, probably will buy a Power Supply with upto 16V and 60A, which can be regulated.
So also, you would recommend MMO and Titan Electrodes?
Would Stainless Steel and Titanium or MMO and platinized Titan work?

markx - 21-9-2018 at 02:30

Quote: Originally posted by Amoled  
Thank you, probably will buy a Power Supply with upto 16V and 60A, which can be regulated.
So also, you would recommend MMO and Titan Electrodes?
Would Stainless Steel and Titanium or MMO and platinized Titan work?


Ti cathode /MMO anode combination is the cleanest and least problematic electrode material choice for chlorate cell application.
Stainless will work as cathode (as will mild steel actually), but expect some corrosion issues in areas that are not submersed in the electrolyte.

Pt anodes can be tricky in solutions that contain chloride. Especially the Pt clad Ti anodes that have a thin Pt layer on top of a Ti substrate. A solid chunk of Pt is virtually nondestructible in reasonable anode applications, but the cost....

I have run a full electrochemical conversion of Cl- -> ClO4- on platinum clad Ti anodes, it worked, but in the end the anode passivated to a noticeable degree.
I worked with homemade Pt clad Ti anode, so I do not know if the chloride content or the questionable quality of the coating was to blame for the passivation (probably the latter). The coating of Pt was really thin on the Ti substrate, but I did not notice any of it dissolving just the Ti became nonconductive due to oxide formation.

Alkoholvergiftung - 21-9-2018 at 02:37

Do you have Problems with corrosion near the electrode Connections? Maybe my electrolysis cell isn t absolutly air tight. But the Connections clamps or wiring Always corrodes.

Amoled - 21-9-2018 at 02:40

Thank you, markx

So Ti Plates are dirt cheap, so in Terms of Price and availability
this wouldn't be a problem.
But MMOs are quite hard to get....
What would you recommend as an alternative... If it would work great, I also could buy a solid chunk of Pt, but you said that this is somewhat problematic with Chloride-Solutions

markx - 21-9-2018 at 03:22

Quote: Originally posted by Amoled  
Thank you, markx

So Ti Plates are dirt cheap, so in Terms of Price and availability
this wouldn't be a problem.
But MMOs are quite hard to get....
What would you recommend as an alternative... If it would work great, I also could buy a solid chunk of Pt, but you said that this is somewhat problematic with Chloride-Solutions


Can recommend the below MMO seller from personal experience:

https://www.ebay.com/itm/MMO-coated-expanded-titanium-anode-...

As for alternatives to MMO...well graphite is one of the few decent practical options. But keep the cell temperature below 40C and current density also low. This will minimize erosion of graphite anode. Eventually you still end up with a dirty solution full of graphite dust that needs to be filtered out to obtain a pure product.

As for other options....well they are more theoretical than practical: manganese dioxide, magnetite, lead dioxide e.g.

Platinum being by far the most expensive one of all options.

macckone - 21-9-2018 at 07:27

Lead oxide anode is the preferred anode if you are going to perchlorate.

MMO will not handle perchlorate well but is fine for chlorate.

I haven't found lead oxide anodes commercially available.
This is a make your own project.

If you aren't comfortable using lead nitrate which is very toxic then this may not be for you.

Amoled - 21-9-2018 at 09:32

Quote: Originally posted by macckone  
Lead oxide anode is the preferred anode if you are going to perchlorate.

MMO will not handle perchlorate well but is fine for chlorate.

I haven't found lead oxide anodes commercially available.
This is a make your own project.

If you aren't comfortable using lead nitrate which is very toxic then this may not be for you.


Would be comfortable using Lead nitrates, but nitrates are somewhat banned here, I have heard it would work with Lead Acetate, and I should take a deeper look into it.
Probably will buy MMO, and a Titanium plate, as this was reffered to as the best here...
Do you if Lead Acetate can be used?

macckone - 21-9-2018 at 09:45

There are methods that use lead acetate but I haven't tried them.

I suggest building a birkeland-eyde reactor of one kind or another.
Mine is designed on a jacobs ladder principle rather than a magnetic sustained arc.
It is powered by a neon sign transformer (15KV/60ma).

markx - 21-9-2018 at 11:29

Sigh.....for practical purposes one can forget about making a workable lead dioxide anode just like that. It is not a practical viable approach. An interesting subject, but riddled with disappointment and hidden bear traps.

For chlorate anode: MMO or graphite
For perchlorate anode: platinum

All of the other options are illustrative at best.

But you are welcome to try and perhaps something interesting and practically applicable shall come out of it :)

phlogiston - 21-9-2018 at 13:54

Buying a small but useful (thin) sheet of even solid platinum will be far less costly than making a lead dioxide anode. Pt-coated Ti is even more cost-effective.

You'll easily spend double the money and 200 times the amount of time on making one (and they don't last forever), and that is assuming you have access to nitrates or nitric acid. Also, do not underestimate the hazards of working with lead nitrate. It is not at all trivial to achieve a level of lab hygeine that will prevent you from getting exposed to soluble lead. Especially the fine spray/mist/aerosol that is produced by electrolysis cells, dissolving metal in hot acid, stirring, etc is difficult to mitigate. Even tiny, tiny droplets of a concentrated lead nitrate solution are significantly hazardous if you value your IQ.

Re voltage:
A 12 V supply will work fine, but a cell running on 12V will waste energy, and heat up -very- significantly as a result.
Think of it this way: you need a few volts to even get the reaction started at all. Activation energy. Anything above that is used to overcome cell resistance. More voltage -> more current -> faster reaction, but more energy lost as heat as well.
You could put 2 (maybe even 3) cells in series. Make sure their resistance is (very approximately) the same. Check by measuring the voltage drop across each cell, it should be similar.
If you would like to run only one cell, you could drop some of the voltage across a few diodes (or perhaps even a lamp, offers free short-circuit protection as a bonus).

[Edited on 21-9-2018 by phlogiston]

markx - 21-9-2018 at 16:36

Quote: Originally posted by phlogiston  
Buying a small but useful (thin) sheet of even solid platinum will be far less costly than making a lead dioxide anode. Pt-coated Ti is even more cost-effective.
[Edited on 21-9-2018 by phlogiston]


I concur to that! Lead dioxide anode is a really captivating subject of research, but no subject to practical application as far as I can see. Producing a workable one in an amateur setting is a rare achievement to be envyed.
Producing an applicable platinum clad titanium anode in an amateur setting is "peanuts" compared to an applicable PbO2 anode.

If one's objective is to produce oxydisers by electrochemical means and not to study the vast anode coupled universe then it makes all the sense to stick to the known workable options.

Amoled - 22-9-2018 at 04:54

Ok, Thank you
Than I will buy a MMO Anode and a Titan Plate as cathode, will be the best.... maybe I will buy a platinized Titanium anode for perchlorate
Will Titanium Cathode Work for Perchlorate? I have the feeling that the Cathode isn't that important.

markx - 23-9-2018 at 22:53

Quote: Originally posted by Amoled  
Ok, Thank you
Than I will buy a MMO Anode and a Titan Plate as cathode, will be the best.... maybe I will buy a platinized Titanium anode for perchlorate
Will Titanium Cathode Work for Perchlorate? I have the feeling that the Cathode isn't that important.


Yes, Ti shall work as cathode very well. It does not corrode and thus will minimize the possible contaminants in your final product. Just watch out for warping of Ti cathode, they tend to bend quite heavily due to hydrogen absorption and if electrodes are placed very close together a short circuit condition may follow. Although mostly the cathode tends to bend away from anode, as the side facing the anode will absorb most hydrogen and expand in the process. If one uses thin Ti rods and not plates, the bending is less likely to happen.
Most other metals tend to corrode heavily under chlorate cell conditions. The parts that are submerged in electrolyte are cathodically protected and do not corrode as long as there is current passing the cell. But the parts that are not submerged (stem or current collector of the cathode) tend to develop a rather quick corrosion rate and the metallic ions will enter the electrolyte, possibly interfering with the operation of the cell.

macckone - 24-9-2018 at 11:20

Lead dioxide on graphite is difficult.
Lead dioxide on lead is easy.

You just need lead nitrate and two lead electrodes.
Pretreat the lead electrodes with sulfuric acid, a low level electrolysis will start a coating.
Then electrolize a solution of lead nitrate until you get a nice adherent coating.

Viola, works for me.

For fireworks this can add some unwanted lead to the perchlorate but it should not be significant.

Just electrolyzing with sulfuric acid between 1.5 and 1.74 volts also works according to one video and this is the method used commercially.

Another method which I haven't tried is lead acetate and sodium or potassium nitrate as the bath with lead electrodes. Then heating the electrode to 110C. This supposedly results in a better adherence and would be easier for OTC since potassium nitrate is more readily available than lead nitrate and sulfuric acids. Lead acetate is easily produced from lead, vinegar and hydrogen peroxide.

The latter method supposedly works for other substrates but requires a lead source for the plating.

markx - 24-9-2018 at 13:45

Quote: Originally posted by macckone  
Lead dioxide on graphite is difficult.
Lead dioxide on lead is easy.

You just need lead nitrate and two lead electrodes.
Pretreat the lead electrodes with sulfuric acid, a low level electrolysis will start a coating.
Then electrolize a solution of lead nitrate until you get a nice adherent coating.

Viola, works for me.

For fireworks this can add some unwanted lead to the perchlorate but it should not be significant.

Just electrolyzing with sulfuric acid between 1.5 and 1.74 volts also works according to one video and this is the method used commercially.

Another method which I haven't tried is lead acetate and sodium or potassium nitrate as the bath with lead electrodes. Then heating the electrode to 110C. This supposedly results in a better adherence and would be easier for OTC since potassium nitrate is more readily available than lead nitrate and sulfuric acids. Lead acetate is easily produced from lead, vinegar and hydrogen peroxide.

The latter method supposedly works for other substrates but requires a lead source for the plating.



Well I do not want to smother your enhusiasm....but have you actually tried to form a lead dioxide coating on a metallic lead anode in a sulfuric acid solution and then worked it in a chloride bearing electrolyte to prove it worthy of being an inert anode for chlorate/perchlorate synthesis?

As far as my humble personal attempts in this field go, they have unfortunately shown that the sulfuric acid method coating is destroyed in mere seconds under anodic conditions in a chloride bearing electrolyte...

macckone - 24-9-2018 at 14:43

I haven't done the straight sulfuric acid method.
My method is to give a light coat with sulfuric acid then go lead nitrate.

It works but the lead is soft and you have to be careful with it because the coating is hard.
It won't handle too much temperature change because the lead will expand and crack off the coating. So you have to run the cell cool. One thing that I found helps with lead is to use rough sandpaper against the surface. Pressing it into the surface not abrading. It creates a dimpled surface that helps the coating 'stick'.

I am told graphite works better but I have never been able to get a good coating that stuck. It could be the graphite I am using, ie. battery recycled.

As for does it work, yes. But I use MMO for chloride to chlorate where a lead oxide coating is most vulnerable. The MMO seems to work better as well. But for chlorate to perchlorate I use the lead dioxide on lead. This works well and the lead coating seems to get better with time.

There is also a method of making a lead dioxide coating with chlorate. That may explain why using it the way I do works.

I am still getting unpacked from the move into the new place but I am planning on firing up the jacobs ladder so I can recreate the process with photos.