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Specialty Chemistry Forums => Citizen Chemist => Topic started by: billnotgatez on June 06, 2004, 03:55:48 PM

Title: Electrolysis
Post by: billnotgatez on June 06, 2004, 03:55:48 PM

I am wondering if someone would comment on the use of various electrodes when doing electrolysis of water. Also some comments on use of catalysts such as sulfuric acid or sodium hydroxide with said electrodes.

Platinum
Gold
Silver
Carbon
Copper

Or any other kinds of electrodes

Regards,
Bill

Title: Re:Electrolysis
Post by: chemicalLindsay on June 07, 2004, 04:28:46 AM

when doing the electrolysis of water you can generally use any metal electrode ,however if you add a little bit  sodium chloride to make a better electrolyte I would not suggest metal electrodes as the sodium chloride can cause weird things to happen to some electrodes ( I used iron one time and the iron startes going crazy and just disintergrating).Carbon electrodes are generally also good but however proper electrodes are best as carbon electrodes when having oxygen being deposited at them can actually react (though often unusual) to produce carbon dioxide gas (C+O2->CO2) (hint I learnt that from reading posts on this site).

Just on the last question ,what do you exactly mean by the "use of catalysts such as sulfuric acid and sodium hydroxide with said electrodes".Did you mean electrolytes instead of catalysts or am I Just missing or not understanding something here.
Good luck on your electrolysis experiment.

Title: Re:Electrolysis
Post by: Scratch- on June 07, 2004, 10:50:17 AM

Most metal electrodes erode during electrolysis and react with what’s in the solution. I use graphite electrodes but they still react in some cases, gold and platinum make really good electrodes but I haven’t been able to get some yet. I don’t think sulfuric acid is a catalyst per say but it makes the solution more conductive so the reaction proceeds faster.

Title: Re:Electrolysis
Post by: jdurg on June 07, 2004, 12:47:48 PM

Well, I have a few pieces of platinum wire, and you can see on the wire where chlorine gas generated during electrolysis of a sodium chloride solution began to corrode the wire.  It's not as bad as on my copper electrodes, but it's still very noticeable.

Title: Re:Electrolysis
Post by: billnotgatez on June 07, 2004, 09:25:21 PM

Whenever I have seen electrolysis -- they used platinum electrodes and a tiny bit of sulfuric acid in the water
I assume they did this to prevent the eroding of the electrodes

Title: Re:Electrolysis
Post by: billnotgatez on June 07, 2004, 10:34:57 PM

Electrode Platinum and Catalyst Sulfuric Acid
Comment?

Electrode Platinum and Catalyst Sodium Hydroxide
Comment?

Electrode Gold and Catalyst Sulfuric Acid
Comment?

Electrode Gold and Catalyst Sodium Hydroxide
Comment?

Electrode Silver and Catalyst Sulfuric Acid
Comment?

Electrode Silver and Catalyst Sodium Hydroxide
Comment?

Electrode Carbon and Catalyst Sulfuric Acid
Comment?

Electrode Carbon and Catalyst Sodium Hydroxide
Comment?

Electrode Copper and Catalyst Sulfuric Acid
Comment?

Electrode Copper and Catalyst Sodium Hydroxide
Comment?

Title: Re:Electrolysis
Post by: jdurg on June 07, 2004, 10:42:07 PM

Electrode Platinum and Catalyst Sodium Hydroxide
Comment?  Your platinum may dissolve as platinum dissolves in hot alkali solutions

Title: Re:Electrolysis
Post by: Mitch on June 07, 2004, 11:04:55 PM

carbon should be fine in either case.