SpudFiles

I've been doing loads more reading on the subject as im finally half way though the process building my dry cell. I was looking to see if there was any way to severely limit the amount of oxygen produced in the reaction, or cut all production completely from the reaction, rather than separate it after the gases have been produced. I then found this in wikipedia:

Care must be taken in choosing an electrolyte, since an anion from the electrolyte is in competition with the hydroxide ions to give up an electron. An electrolyte anion with less standard electrode potential than hydroxide will be oxidized instead of the hydroxide, and no oxygen gas will be produced. A cation with a greater standard electrode potential than a hydrogen ion will be reduced in its stead, and no hydrogen gas will be produced.

So correct me if im wrong, but all I need is an anode made of a metal that is more resistant to electricity than the electrolyte? And this would mean that the anode would oxidise instead so only hydrogen would be produced?

I don't know if i am to late but i answer the question anyway

To make a good electrolysis/drycell you will need an anode and katode that cant corrode. Aluminium, copper and normal steel wont work at all.
I suggest that you buy stainles steel, that will work well, and of course both the anode and catode is made by the same material.

There is many choices of an electrolyte, it depends in what way you is going to use it. I would say that your best options is baking powder, Potassium hydroxide (sometimes hard to get your hands on, is verry corrosive) and Sodium hydroxide (often used as a drain cleaner allso verry corrosive).

If you are going to use your cell in short periods of time (not in a car) and you are pretty new to this, i recomend baking powder becaus it is not dangerous to work with at all. But eventually it will discolor your water.

The second best choice is NaOh it produces cleaner hho and will keep your electrodes clean but remember that it is dangerous to work with. Handle it with care.

KOH is the best electrolyte of the ones i have said. It is a stronger electrolyte it will do the same thing as the NaOh but it will work better. And allso remember that this one to is verry caustic, you dont want to get it in your eyes

I hope i helped you with something feel fre to ask more questions!
Sry for my bad english
good luck!

Edit* I have been looking for a verry long time for an effective electrolyte that is not caustic or corrisive but it seems like that is allmost impossible im sure you can find it somewere but i think you will have to search for a while then

Thanks for the reply, but I did abandon this method a while ago. I am now looking into making hydrogen though chemical reactions between acids and metals rather than electrolysis as this produces just H2, not oxygen aswell.

This makes the gas alot safer to work with too and opens up possibilities to have small cylinders of compressed hydrogen with no significant risk of an accidental ignition.

okay!
That seems like a good idea what chemicals do you plan to use?

Hydrochloric acid (HCI) and Aluminium, although I have also considered requesting a bottle from a UK gas supplier. I doubt I will use this as an actual fuel for an everyday hybrid, I just want to explore the gases properties