Definitely hold your breath around people trying to produce ammonia.

That's for a 1cm^2 electrode, as far as I remember not precious-metal rich either.

So you only need an electrode about the size of Monaco to get 1 kg per second. Hopefully you can use some kind of foam or something.

They sometimes use weird techniques to produce electrodes with specific area on the orders of thousands of square meters per gram. Even if it has to be flat, there's little holding you back from stacking 10k layers as long as you can manage the heat.