I did the $\ce{H2O}$ electrolysis experiment a few times, but every time a huge amount of the oxygen reacted with its corresponding electrode. What material should the electrode be made of in order to maximise the amount of oxygen I get?
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$\begingroup$ a platinum electrode would be inert in such an electrolysis experiment. $\endgroup$– MaxWCommented Nov 15, 2015 at 2:20
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$\begingroup$ Graphite electrodes also work quite well, they can be found in pencils and if they by any chance do erode, they can be replaced cheaply. $\endgroup$– sadljkfhalskdjfhCommented Mar 20, 2016 at 13:28
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1 Answer
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It depends on the electrolyte as well as the electrode material. For example, $\ce{NaCl}$ releases atomic chlorine at the positive electrode, quickly attacking most materials except metals of the $\ce{Pt}$ group, as @MaxW mentions.
$\ce{NaOH}$ or $\ce{KOH}$ are a bit gentler on the electrodes. Run the apparatus at a low over-voltage to avoid damaging them. Coated nickel electrodes are suggested for use with alkaline solutions.
answered Nov 15, 2015 at 3:12