How to Generate Hydrogen and Oxygen

[John1397]

I have generated hydrogen and oxygen from salt water and water from batteries and have used stainless steel, copper, and aluminum electrodes using electricity, but the electrodes keep disappearing to fast. Is there a way to generate hydrogen and oxygen without this problem or by maybe changing volts/amps combination of electricity and what would be the best liquid or any other methods?

John

 

[Borek]

Solution of sulfuric acid or sodium hydroxide would be slightly better than the salty water.

The more inert electrode the better, AFAIK carbon rods, stainless steel and noble metals are the most stable ones.

Test the voltage - after some point increasing the potential difference doesn't speed up the reaction.

 

[NascentOxygen]

I have generated hydrogen and oxygen from salt water and water from batteries and have used stainless steel, copper, and aluminum electrodes using electricity, but the electrodes keep disappearing to fast. Is there a way to generate hydrogen and oxygen without this problem

Hi John. This phenomenon has interested me for some time. It's my conclusion that the disappearing electrode is not primarily due to chemical action, but rather attributable to mechanical action where cavitation erodes surface material from the electrode. Perhaps a harder/stronger substance may hold up better; if so, this might be a vote for stainless steel, though I haven't performed comparisons.

You can't in every case use the same conductive material for both anode and cathode. For example, you've never had success using aluminium for the oxygen-liberating electrode, have you? While you can use lead for either electrode in acidified water, you are limited to using iron for only the hydrogen-liberating electrode.

You will also observe how the gas layer on the electrode material forms something like an insulating layer around the electrode, hampering your attempt to push through more amperes and speed up the cell's production of gases.

Happy experimenting!

http://imageshack.us/scaled/landing/109/holly1756.gif

 

[John1397]

Seems like if your electrodes disappear you would be wasting energy I always used 12 volts from car battery I adjust amps draw by how close you place your electrodes. I tried distilled water and I new already that this would not conduct.

 

[NascentOxygen]

Seems like if your electrodes disappear you would be wasting energy I always used 12 volts from car battery I adjust amps draw by how close you place your electrodes.

You would be both surprised and disappointed by how little influence electrode separation has on current, once things settle down. Making electrodes having much greater surface area gives some improvement, but those too soon become coated in a layer of gas. I think rapid stirring of the electrolyte will be the best you can do t reduce the effect of the insulating layer.

You can always use a metal bowl, e.g., aluminium can, and make the container itself one of the electrodes.

Most of the energy wastage reveals itself as heat, I think you'll find, warming the electrodes and electrolyte.

http://imageshack.us/scaled/landing/109/holly1756.gif

 

[DrZoidberg]

Aluminum and salt is a bad combination for this.
Stainless steel should work well enough with sodium hydroxide or alternatively sodium carbonate or sodium bicarbonate.