SpudFiles

ok, lately ive been thinking of making an electrolysis machine, and ive been trying to think of ways to make it faster or more efficient. I would like input on which ones will work, and for the ones that work, which one would be the most efficient.

in the pics the things are kinda color coded:
the blue and red are the opposite electrodes
and white or grey is pipe

and dont yell at me for bad pics as i only had bout 20 min to make all three
and imagine that this all is inside a container

The design of an efficient electrolysis cell is really pretty straight forward.

Rule number one: The electrodes should be plates and not wires. The larger the surface area the faster the cell will produce hydrogen and oxygen. Usually, the electrodes are simply flat plates.

Rule number two: The plates should be as close together as possible but not so close that the bubbles stick between the plates.

For example, see "mr. splitter"

ooo, that helps alot, thank you

but with that example i cant figure out how he separated the H2 and O2

Yeah, also I believe the electrolysis machine will corrode the plates if they're made out of something corrodable.

i know which is why i will use stainless steal, or carbon

You'll be better of using carbon. Stainless Steel will eventually start to corrode.

Yeah, you need something inert like a carbon electrode or a platinum electrode (but i don't think many people can afford a platinum electrode and if they could i doubt they would use it as an electrode)

You can also add concentrated sulfuric acid as a catalyst (not sure if you already have) and as someone said, make the electrodes with as much surface area as you can.

Also, remember Faraday's Law of Electrolysis which can be found on google or wikipedia.

auctually i was going to use KOH (Potassium Hydroxide), because i read somewhere bases are better on the electrodes, and i read how to make KOH from wood ashes.

Edit: I cant type

sandman wrote:auctually i was going to use KOH (Potassium Hydroxide), because i read somewhere bases are better on the electrodes, and i read how to make HOH from wood ashes.

Umm, HOH is water........, unless you mean KOH.

Do you mean you will use KOH as an electrode or as the catalyst?

I don't think it will be very good as the electrode since it will disassociate. But as a catalyst I'm not sure, we just use sulfuric acid.

yes i changed it now
KOH as the catalyst (aka electrolyte)

sandman wrote:yes i changed it now
KOH as the catalyst (aka electrolyte)

Oh right cool. I'm not 100% sure if it will work for the following reason. Oxygen is created at the anode by the oxidation of water, and hydrogen is created by the reduction of water at the cathode. Then concern is what if potassium gets created at the cathode, it is more reactive i think it will have a tendency to take the electrons and form a solid. I might be wrong about it, but i do know its higher on the e-naught value sheet than the reduction of water and i think that means it is more electronegative, meaning it has a higher need for electrons.

The reason sulfuric acid works with it is because the sulfate ion is lower down on the table compared to the reduction of water, so water is more likely to be reduced.

but with that example i cant figure out how he separated the H2 and O2

He doesn't, he just let it mixes.

And for this application stainless should work fine, expecially if you get extremely high quality. I used cheap home depot stainless steel hardware and after tens of hours of use I have yet to see any corrosion.

Just a suggestion, but if you wanted to seperate the gases, you could use stainless steel plates and seperate them by a thin sheet of plastic (but allow water to surround the entire plate, maybe a 1mm clearance). and then have a gap at the bottom so water can pass through the entire inclosure but the gas will not pass between paltes and mix because it goes upward. Anyways just my two cents.

With the proper electrolyte the metal the electrodes are made of doesn't really matter all that much. Zinc plated steel works well, pretty much any steel works pretty well ...

Zinc plated steel is nice becuase you can get it at the local hardware store for very cheap, as flashing.

Over time the electrodes will corrode but they should last for a very long time with the correct electrolyte and if you avoid applying too much voltage to the cell.

KOH (or NaOH) really isn't a catalyst, it is the current carrier. You have to have ions in the water for it to conduct electricity. Pure water is a terrible conductor of electricity since the concentration of ions is so low (~0.0000002 molar). Adding a couple grams of KOH will increase the salt concentration and reduce the resistance by ~million fold.

Oh ya, and...
Rule Number 3: Don't use any higher voltage than what is needed. Higher voltage will not make the cell produce H2 and O2 faster. Higher voltages will only make other electrolysis reactions occur, ones which you really do not want to happen.

Hi, i have a few things to add:

-For an electrolyte i recommend using NaOH wich is simply buyable in your local supermarket under the name of "Drain cleaner" http://en.wikipedia.org/wiki/Drain_cleaner
Get the one with white solid little balls.
btw: you cant use NaCl as electrolyte because you will create Cl2 gas. (didnt know if you knew bust just wanted to tell it)

-For the electrodes you can get carbon rods out of old batteries. Just open up some Zink-carbon batteries and get the carbon rods out of em. (dont open rechargable or alkaline batteries, they dont have the rods)