Sciencemadness Discussion Board

Lead dioxide anodes

S.chegini - 4-9-2019 at 05:03

Dear friends

One of my friends introduced you to me as an expert in the field of lead dioxide anode manufacturing. I have made an anode in an experimental setup and i want to utilized it in a perchlorate cell. However, there are some questions in this field for me.

1. I have heard that the anodes should be activated before electrolysis in perchlorate cell. How can i do it?

2. The initial quantity of sodium floride in my electrodeposition bath is about 2 g/lit. How much sodium floride should be added to the electrodeposition bath after manufacturing of an anode with the length of 30 cm and diameter of 4 cm and coating thickness of 3 mm

3. The surface of deposit which is obtained at temperature of 85 degree centigrade is rough. How can i decrease it?

 

The Best Regards

S. Chegini.

underground - 4-9-2019 at 06:07

Why don't you just buy them from alibaba. This is what most people do

Pyro_cat - 6-9-2019 at 22:52

Quote: Originally posted by underground  
Why don't you just buy them from alibaba. This is what most people do


Certain satisfaction from making stuff from things you can find in your environment.

Sure you can buy potassium nitrate but you can also make it from urine.

underground - 6-9-2019 at 23:01

Making LD anodes is a very hazardous process. Lead nitrate is very toxic.

yobbo II - 8-9-2019 at 06:28



https://geocitieschloratesite.000webhostapp.com/

Laboratory of Liptakov - 23-9-2019 at 12:31

Every beginner has tendention make all from nothing. Is it an basic feature of the researchers. But sometimes it is in basically impossible. Created the quality lead dioxide, in homemade conditions, on the reliable carrier substrate is one from them. ...:cool:...LL

caterpillar - 23-9-2019 at 16:18

Quote: Originally posted by Laboratory of Liptakov  
Every beginner has tendention make all from nothing. Is it an basic feature of the researchers. But sometimes it is in basically impossible. Created the quality lead dioxide, in homemade conditions, on the reliable carrier substrate is one from them. ...:cool:...LL


Really? But what if I take then from an accumulator? When it is charged, one electrode contents lead, the other lead dioxide.

Laboratory of Liptakov - 23-9-2019 at 23:01

This is a great idea and logical judgment, but it does not work. The battery electrode disintegrates within minutes. If it were so easy, everyone would have done it long ago. But you can try it....:cool:...LL

caterpillar - 24-9-2019 at 00:40

Quote: Originally posted by Laboratory of Liptakov  
This is a great idea and logical judgment, but it does not work. The battery electrode disintegrates within minutes. If it were so easy, everyone would have done it long ago. But you can try it....:cool:...LL


But why? It lives in an accumulator and withstands many cycles. Why should it disintegrate in the solution of NaClO3?

rockyit98 - 24-9-2019 at 03:34

i keep sodium sulfide with in a hand of reach when i'm dealing with toxic soluble compounds .like Pb Cu Ni Mn Cr Hg salts. you cannot be too careful.
Making Graphite Substrate Lead Dioxide Anodes https://www.youtube.com/watch?v=tXSpqy2TNWo

markx - 24-9-2019 at 04:16

Quote: Originally posted by caterpillar  
Quote: Originally posted by Laboratory of Liptakov  
This is a great idea and logical judgment, but it does not work. The battery electrode disintegrates within minutes. If it were so easy, everyone would have done it long ago. But you can try it....:cool:...LL


But why? It lives in an accumulator and withstands many cycles. Why should it disintegrate in the solution of NaClO3?


In perchlorate cell the anodes are strongly polarized. About 2V vs. SCE for optimal synthesis of perchlorate with PbO2 material. As far as I know lead acid batteries do not reach such polarisation levels. This is perhaps one of the contributing factors to anode deterioration under perchlorate formation conditions.
A lead dioxide anode that holds up to operation very nicely in sulfuric acid solutions tends to disintegrate quite fast in a perchlorate cell.

For reference regarding perhlorate synthesis on PbO2:
http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.824...

phlogiston - 24-9-2019 at 08:05

Quote: Originally posted by S.chegini  
Dear friends

One of my friends introduced you to me as an expert in the field of lead dioxide anode manufacturing. I have made an anode in an experimental setup and i want to utilized it in a perchlorate cell. However, there are some questions in this field for me.

1. I have heard that the anodes should be activated before electrolysis in perchlorate cell. How can i do it?


I don't think I have ever read about an activation step (where did you come across it?), and it is certainly not essential. I and others have used lead dioxide anodes directly after plating and that seems to work fine.
Quote:

2. The initial quantity of sodium floride in my electrodeposition bath is about 2 g/lit. How much sodium floride should be added to the electrodeposition bath after manufacturing of an anode with the length of 30 cm and diameter of 4 cm and coating thickness of 3 mm


The electrodeposition bath does not usually contain fluoride as far as I am aware, but it is added to the perchlorate cell electrolyte to improve current efficiency. This is optional. Perchlorate cells can work without it, at the cost of reduced efficiency. 2 g/L sodium fluoride is a typical concentration for that application. I don’t think fluoride is consumed in the reaction, but I can image small amounts may be lost with the harvesting of raw, crystallised product, and perhaps as volatile HF, depending on cell pH. I don’t recall reading anywhere about a need for periodic re-addition of fluoride.

What is the composition of your electrodeposition bath, and what is the substrate that you are plating?

Also take note of sodium fluoride's highly poisonous nature, in your consideration whether to add it to your cells or not.
Quote:

3. The surface of deposit which is obtained at temperature of 85 degree centigrade is rough. How can i decrease it?


Keep in mind that roughness is not necessarily a problem in itself, as long as there are no pits/defects in the coating. That being said, several methods are known. I have obtained extremely shiny deposits by plating onto a rotating anode.
Other methods are adding certain surfactants to the plating bath (I specifically recall cetyl trimethyl ammonium bromide being used), sonication, and suspending abrasive particles in the bath with strong stirring. All of these have the effect of removing bubbles from the anode as it is being plated.

Another reason for a rough coating may be excessively high current density. What current density are you using while plating?

If you haven’t seen it already, there is very long, but great thread on lead dioxide electrodes: here. Well worth the read.

RogueRose - 26-9-2019 at 07:06

It depends on what you need. Are you talking about commonly available chemicals or harder to find chems? Ebay is good of course, sometimes prices can be high or questionably low.

There is a company called "the science company" that has a good selection of chems for a good prices.

There are a few pyrotechnics companies that have a very nice selection of chems as well, do a search as I don't want to name them here b/c of stupid people (not referring to users here..). PM me is you want.

Pottery companies are also a good source for chems that are used in their profession, which is actually a pretty wide range.

Biodiesel producers have a nice selection asl well from acids, to bases.

Pool chem companies.

If you are looking for something specific message me and I'll see if I can point you in the right direction but if it is for more advanced chemistry, I'm not going to be much help there as those suppliers often need businesses for shipping or sales.