What's the best electrolyte for water electrolysis?

Hello,
I'm electrolyzing H2O to produce H2 + O, but I'm not sure what the ideal electrolyte would be. NaCl works, but I am somewhat concerned about the Cl coming off the cathode. How would I find out what quantity of Cl would likely be produced? I am experimenting with the intention of building a hydrogen torch, so process will be happening on a relatively large scale.

Also, I'd like to find out how to determine what factor is limiting the hydrogen production -- is it the conductivity of the solution, the surface area of the electrodes, voltage applied, or the chemical relations between the electrolyte and the electrodes?

If anyone can answer these questions or direct me to suitable resources online that would be great.

Thanks,
Adam

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I read somewhere that KOH

I read somewhere that KOH was. Whatever that is. Is this potasium hydroxal?

theres many different

theres many different solutions you can use both acidic and alkaline. What you are trying to do is drive the solution Ph either very hi or very lo to promote electron flow. Potassium Hydroxide (Koh) is cheap, pure, easily found, takes very little to raise the Ph,is fairly safe to handle and is eco friendly. It's draw-back is that the solution can "almost" freeze in the northern hemisphere. A battery acid solution on the other hand will not freeze and the solution can also be driven to higher temperatures than Koh.
The limits are controled by the plate area, the amperage, the voltage and the solution Ph. Alkaline solution should be about 27% Koh by weight, voltage depends on the distance between the electrodes. Plate area is proportionate to amps per sq inch to reach hydrogen bubble saturation on the plate. Flat plates do not work well because hydro bubbles are very sticky and quickly saturate the electrode surface. The electrode material is also very important, remember that you are transferring the electrons of that material between the electrodes and thus you can build up a coating on the electrode that creates resistance to electron flow.

I need a substitute for

I need a substitute for potassium chloride... in large quantities (tons) .....any sugguestions?
Thank you

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