Make Manganese Dioxide Electrodes (for chlorate or HHO cells)
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- čas přidán 28. 03. 2010
- How to make Manganese Dioxide Electrodes that can be used for chlorate cells or HHO cells and a few other electrochemical processes requiring inert anodes in oxidizing solutions.
Make the electrode is fairly simple. First a titanium strip is sanded to give a clean surface and then etched with hydrochloric acid to activate it. Cobalt nitrate solution is applied in a thin layer and then heated to 300 Celsius to decompose (pyrolyze) the cobalt nitrate into cobalt oxide. the loosely adhering cobalt oxide is washed off and then new layers of cobalt oxide are applied. Usually between 3 to 10 layers.
Then manganese nitrate is applied and the process repeated to make manganese dioxide. Another 10 to 50 layers may be applied.
Optionally, a further layer of manganese nitrate by electrolysis may be applied by using the electrode as an anode in a solution of 90 grams manganese sulfate, 500mL water and 12mL concentrated sulfuric acid. Copper or titanium is used as the cathode and a current density of about 10ma per square centimeter is used. A short run time of a few minutes or so puts a thin layer of manganese dioxide on the surface that seems to reduce permanganate production, but does not eliminate it.
In the future i'll be working on a lead dioxide electrode. - Věda a technologie
Haven't heard of anyone making a good PbO2 Anodes but still it is seen as the Holy Grail of Anodes for Perchlorate Cells since you can oxidize from KCL directly to KClO4.
this guy is a genius the one with steel wool and the potassium chlorate was epic!
@coldsn In theory anything could work. but titanium is good because even if you missed a spot, get a scratch, or if there is some random flaking due to flexing or thermal expansion/contraction, the titanium won't corrode when it comes in contact with solution, it just passivates. A more reactive metal like copper or steel would start corroding, the corrosion then spreads underneath the layers and eventually the whole thing is destroyed.
Tantalum and niobium work too, but titanium is easy to get
i love these videos, i love the feeling of actually understanding most of it. the best part is not understanding all of it. thanks for another brilliant vid guys!
@mV33rs Stainless steel (as it's called) only means stainless or "rust-free" under regular environmental conditions, rain, air, snow, salt, etc.
But under the extremely harsh conditions of an eletrolytic cell (especially chlorate) it's destroyed rather quickly.
Very few metals like platinum and titanium can take those kinds of conditions.
I can't get enough! Love these vids
Wow yours is the 1st video ive seen where all the captions represent what you are saying.
THANK YOU, FINALLY A VIDEO THAT EXPLAINS WHAT I WANTED!~!!!
@TheMnO2 Very interesting! i'm intrigued by your use of vanadium. Thanks for sharing. you really should make a video on your process!
Excellent vid, NR- I've watched it more times than most of the others. I look forward to seeing a follow up including but not limited to PbO2, other surface primers than cobalt. Mention was made of ruthenium, and of vanadium.
I hope there is also something on bromate and iodate in an upcoming video.
Thanks NurdRage! I've made some Lead(II)-oxide electrodes out of titanium and lead(II)-nitrate solution. They're excellent for making chlorates, especially with some Potassium fluoride to form a protective-layer. Please make more videos like this cause they are really useful and worth to reproduce! Greetz
wow.. it would be great if you upload it on you tube.. do you have any documentation about it?
@mV33rs Titanium is best due to it's chemical inertness and mechanical strength. Other materials would dissolve if even a tiny bit of manganese dioxide was scratched off.
I enjoy your vids!!!
I have no idea what he is talking about but it is still fun to watch
Nice video, keep it up!
@Gmc42082 I intend to eventually make MMO electrodes too.
but yeah, this is not better than a commercial product. I just wanted to show a homemade way of creating a semi-viable electrode.
@AngryBF2Nerd no, it just has more to flake when you have 20 layers. the rate of flaking is still the same.
you've made a lot of videos latly. well played, good quality as well this could be really useful thanks
I didn't think that I was ever, EVER, going to see this video
@NOBOX7 Interesting! thanks for your observations, i'll ponder it a little more.
@soyunclonyque absolutely, i'm researching what additives would be best, i'm not sure chelating is the way to go but i'm sure i do need to add something more to control the deposit and how it forms.
I have to agree it does sound softer.
@aCagedApe Yes you can, i haven't tried it yet, perhaps in future, I don't know when i'll have time though.
THUNKYOU VERY MUTCH YOUR SHOWS YOUR SUBJECTS ARE VREY INTRESTING
This is so extremely cool and informative. I really like your videos nurdrage.
About the lead. When I was younger I tried to make lead soldiers instead of using tin. When melting lead you get unhealthy fumes. So when I was about to get to sleep I started to shiver like craz and my body shi
@dragonridley Since when was the issue about price?
I thought the issue was if the oxides you mentioned worked (V, Cr, Fe, Ni).
thx! great video!
@capnquack the oxides are far too brittle to be hammered. It might work with a malleable metal like copper, but hammering oxides is like hammering rock, it just breaks it.
@dragonridley yeah, my bad.
Nonetheless, price doesn't change the fact that Ir works.
Since you don't have a post on PbO2 anodes, i'll have to comment here- I thought of an idea for PbO2 anodes... It DOES have a couple of flaws, though, but seems simple enough otherwise: on a porous substrate, allow it to soak up a solution of Lead IV acetate. I'm not sure what the thermal decomposition product of it is- probably reduction of lead. But it is powdered PbO2- Just add water (and hope thermal expansion does not crack the ceramic). The other problem this is resistance. love your vids.
@TheMnO2 interesting, i'm pleased it's working for you.
You r THE BEST!!!!
Sorry for the stupid comment :)
@nattsurfaren yeah, thus why i need to determine a safe way of doing this. Preferably one where i don't get poisoned.
you mentioned applying manganese dioxide electrolytically to a copper electrode. Is the initial cobalt layer required with copper?
Nurd, i got lead sludges from my dad like 500grams , my plan is to melt it in a small furnace i have and cast em into round bars or flat bars (or maybe hammer the round bars to make ethem plat in the "inside of the cell part" and round in the electric contact part, will make everything outside, backyard. then in diluted sulfuric acid going to aply electricity to form on both electrodes a lead dioxide surface. then share results maybe a video or photos.
also, your voice is awesome.
awesome video.. as far as flaking goes, you either need a thin coating, nanocoating, that won't flake, or you need something that deposits as a loose crystalline needle structure, that can take some flexing, because it has a lot of voidspace, and won't crack.. znpo4 paint pretreatment baths that use titanium seeding, and grow massive crystals of znpo4 whose solubility at high temp is massively dependent on a 0.1 increase in pH somewhere between 3-4, is an example.. thick and adheres well
@KarriKoivusalo Those are usually on aluminum, unfortunately they would be destroyed pretty quick.
Thanks muchly for this, very interesting. I wonder, do you think other oxides like those of say V, Cr, Fe, or Ni would also be worth a shot for a coating?
I also am wondering if including some kind of silicate (say, sodium silicate) in the metal nitrate solution may lead to co-deposition of SiO2 leading to a mechanically tougher coating without adversely affecting its redox properties?
Lead sounds like a good idea to me - good luck with that.
Very cool, I teach chemistry at a high school in Texas and we just did your creation of Manganse Sulfate in lab using the batteries, etc. I wonder if to avoid the flaking problem you need to prime the titanium better first, almost how paint has a primer on a wall, you might need to use another salt or something to give it the oppurtunity to bind at the molecular level. Just a thought!
@Neilidity some oxides will work, some won't, i don't think the ones you listed will work. But Ru, Ir and Pb will
You rock!
@TheMnO2 interesting, i'll keep it in mind.
@coldsn its a great idea and worth testing. I don't have the equipment to perform such tasks but if you could let me know your results. Eventually in the future i might get/build something that can do those things. its certainly an interesting idea.
@freakin1random yeah, i'm thinking adhesion is an issue, i'm still working on the problem.
@The0Burger0King that substance itself would probably be destroyed under oxidizing conditions.
Lead dioxide would work, but then i would use a pure lead dioxide electrode instead :)
i wonder if rapping the anode in string would give the dope extra integrady ?
i am going to try rapping a carbon anode in cloth very tightly but using a thin layer,
i think that wen sum materials absorb the elite they are "exploded " from the inside by the evolusion of gases?
@Lodoss1986 I already showed in a previous video that uncoated titanium cannot be used due to passivation
Can you get rid of the oxides on the titanium by running it as a cathode?
nurd rage ftw
good video man
@Serostern Doesn't matter if you have billions, gold electrodes still won't work.
You'll need a platinum electrode.
@panzuman yes
Is this applicable to tungsten based compounds? I have a few kg's of fairly fine pure tungsten powder, Setting it alight gives me WO3(tested) then treatment with ammonia solution should give me ammonia paratungstate(untested) which(according to wikipedia) decomposes at 600*C to WO3.
I'm unsure as to whether this will give a suitable surface covering of WO3 for use as an electrode though, any input would be appreciated!
Hello Nurdrage
I have found that it is easier to make perchlorates by simple oxidizing chlorates with strong oxidizers, like ammonium dichromate and making a heat decomposition. Remaining unreacted chlorate can be removed by another heat decomposition using sodium bisulfite.
I mention this so there is no need to mess around with the toxic lead and lead dioxide, for people wich would need these electrodes for the prodcution of chlorates and perchlorates.
fair point, I forgot that aluminum hydroxide forms when aluminum is oxidized in a solution, not aluminum oxide.
@Ar0999 That's because i make them myself by hand.
@dragonridley Doesn't change the fact that it works.
Thanks Nurd.
What kind of electrode are you making? Anode or Cathode
Hey Nurd, did you ever experiment with the lead dioxide electrode concept? I'm currently working on one myself and would look forward to you possibly covering the subject in a future video.
Check out the Mysteriusbhoice channel, he's pretty much perfected the PbO2 electrode plating process and he's a great guy and really helpful.
4:40 same question can cobalt be replaced with other cheap chemical ?
@j822bosh its a good idea, i haven't tried it yet, but certainly worth looking into.
the flaking problem might be caused by the cobalt oxide forming unevenly on the titanium. As you said, some of it flakes off as you wash it. When it flakes off, it may create some holes in the layer. Then the manganese oxide can´t stick to the plate very well, either....
So you might want to try to coat the titanium with the cobalt oxide by electroplating, too (if this is possible in any way).
just my idea.
nice video!!
can i use silver for this purpose??
plz tell me
@blakewade01 There are better materials than cobalt oxide, but cobalt is the easiest one to get. Sold at pottery supply stores by the pound.
@coldsn aluminum corrodes too
@NurdRage i have tried using nick welding rods as electrode and was able to get a blake oxide build up that conducts but not very well ,, i noticed a 20 amp drop in current on a 70 amp cell, this was done with sulfuric acid i think as the eleite ill have to chek my notes, it may help ur research
About the flaking after the final addition in this video, couldn't you use the zinc galvanization process from that video on that? Would that be enough to prevent the flaking? Will the galvanization even be possible?
titanium can be found on common aluminium cans found anywhere. the "ring pull" is titanium.
Interesting. Have you tried hammering to make the flakes stick better? I know it's weird, but when my old chem teacher electroplated his keys for us, he showed us how he keeps it from flaking by hitting it with a hammer (just the top flat part of the key, obviously). It was with copper, which I know, obviously, has the ability to be flattened, and I don't know the properties of what you were using, but maybe that might help?
Have you tried to use bare titanium for electrolysis of brine? As I've read, titanium anodes were used in chloralkali process, but I'm not sure were they bare or had a coating. You can actually buy titanium mmo anodes, where mmo is reffered to ruthenium and titanium oxides.
what about antimony trisulfide? ive read its also used as an eleectrode coating?
is there any other layer you could stick in between the Co and the Mn oxide layers?
Maybe the Manganese is in some form reacting with the Co oxide. just in a very low amount so that it flakes?
+NerdRage activate the metal and hit the metal with naoh and isopropyl alcohol before plating to remove any oils. that way help with the flaking. can you help me fine a trivalent chrome plating system that is bright? needs to be brush and immersion.
Your voice sounds softer today.
I think you should try putting a knurl on the plate, The crushing of the material will create plenty of cracks and crevices for your plating to stick to. The surface of the titanium looks too shiny for what you're doing.
@sciencoking If you can find a way to electroplate cobalt oxide (using home-lab setup) let me know. :)
@Narutopuneet I don't think so. but why dont use graphit-elektrodes (very cheap) and coat it with everything u want?
@NurdRage
The problem I would see is a potential change in the structure, which might render the CoO insulating. If I had a kiln on hand, I'd try it. Question, how important is the titanium substrate? It would seem that it never comes into contact with solution, so anything upon which manganese oxide and cobalt oxide would 'stick' to should work.
@nurdrage
what about paladium and iridium?
they're nobles metal just like platinum
they're also easier to obtain cause they're used in everyday applications, no?
Can i replace cobalt nitrate with Manganese Nitrate ?
Do MMOs have an "expiration date"? Or they are similar to Pt electrodes that "never" get corroded?
Thanks!
@NurdRage
While Mn and Co oxides crumble and flake easily, is there any good way to press or sinter them into a semi-ceramic structure? I wonder because Cobalt salts are commonly used as glazes for fired ceramics.
If CoO is conductive, and is used as a pottery glaze, maybe it can be milled mixed shaped and fired into a solid ceramic electrode? If not directly, then as a glaze over a thin ceramic structure.
Hi nurdrage. Good video I want to ask you something, Where can I buy titanium? what kind of stores can I find it? sir. I hope your soon answer.
Can you use any other metals instead of titanium?
I'm looking forword to see your Lead dioxide electrodes.
@scbaldwin13 I think i'll let my videos speak for my education and my ability, i think that's far more telling then what piece of paper i have hanging on my wall ;)
que lindo
Can i use graphite instead titanium ? Coating mno2 on graphite ?
my words exactly
@miesrah12 because platinum extremely chemically resistant, safe to use, electrically conductive, doesn't passivate as badly as titanium and decays very slowly,
@panzuman 4 layers
ok, thanks
What about aluminum? Ideally, HCl should eat right through the passivated layer to activate it, though I suppose with passivation time in the range of tens of milliseconds, it would be difficult to process quickly enough... (what about gradually replacing HCl with the plating solution?)
@TheMnO2 Interesting! What temperature did you do the baking at? I would imagine that when you bake it, It would make NiO, and under anodic conditions, convert to NiOOH (especially when there is a bit of hypochlorite in sort-of-anolyte) NiOOH as an electrode material in basic conditions (like chlorate cells) seems pretty ideal. I'm not quite sure how to make it adhere. It would be fun to play around with.
400c final is 375c
Hi I like know what other metal is posible used instead of titanium?
@getzkazer What is the layer of thickness on the lead II oxide? It must be VERY thin, as I don't think Lead II oxide has that great of conductivity.
Is it possible to apply black nickel oxide in between cobalt oxide layers? Trivalent nickel oxide is conductive and nickle oxides are available from pottery suppliers. The coating of inert electrodes is strikingly simular to the semiconductor research. Consider doping materials for your cobalt oxide interface to modify its structure.
This is very useful, thank you!
Also, with the electrolytic manganese dioxide flaking, maybe you could mix some other metal to form oxides that adhere better to the substrate and the MnO2 itself? maybe tin could work?
Yes antimony or cerium Doped Tin dioxide SnO2
@odysseus9672
i tried it with ultra-pure lab grade stuff, same problem.
if u insert it into hot HCl (aq) it won't splash? and can TiCl3 be used for other stuff?
what about melting and molding a bar of lead, then axidize it to superficial lead dioxide , just sugesting
Sorry I pressed submit before I was finished.
Ok I shivered like crazy and I freezed. I had to phone to a hospital to contact the poisoning information experts. They said if it got worse I had to visit the hospital. Thankfully this stopped after a while but I got really scared.