@zuki raw graphite blocks don't seem that good. Just amorphous carbon is doing better and would be easy to get or make myself. Iron oxides might perform better tho, that's what these guys usually use to dump their electrons already and is prob easy to turn into a nice surface too. I'll just paint graphite onto some steel mesh for the first try tho.
Membranes i can just use earthenware, found some paper that added starch to make it more porous and i wanna try that.
Cathode is just gonna be graphite-plastidip paint, that seems good since apparently graphite catalyses the reactions i need well and plastidip works as a proton membrane too? idk if i'll have to add metal mesh to get conductivity high enough