You get hydrogen gas and chlorine gas; one is fuel, the other feedstock for any number of industrial processes. (Electrolysis of an NaCl solution is already on

You get hydrogen gas and chlorine gas; one is fuel, the other feedstock for any number of industrial processes. (Electrolysis of an NaCl solution is already one of the standard methods of producing elemental chlorine for lab and industry use. The efficiency isn't great, but the method described in this paper appears to improve considerably on that, assuming it can itself be efficiently implemented at industrial scale.)