I was actually planning to put a lead dioxide anode in some plaster of paris(CaSO4) being its already an electrolyte while using some other metal as the cathode in a very dilute solution of sulfuric acid to reduce the hydrogen to gas forming OH, and no O2 evolution, preventing H3O production due to the anode being locked in the block of plaster.
Being the solution is acidic, I was hoping to produce some dilute H2O2 maybe as a test run then move on to more interesting things.
Interesting you mentioned sulfate, that's exactly how I make sulfuric acid or if sufficient voltage is supplied and the conditions are correct peroxydisulfuric acid.
Actually, I am looking for a way to either reduce or oxidize not both. Though it seems there will be some oxidation taking place due to the porosity of gypsum.