Herein discussed is an electrochemical reactor comprising a first electrode, wherein the first electrode is liquid when the reactor is in operation; a second electrode having a metallic phase and a ceramic phase, wherein the metallic phase is electronically conductive and wherein the ceramic phase is ionically conductive; and a membrane, wherein the membrane is positioned between the first and second electrodes and is in contact with the first and second electrodes, wherein the membrane is mixed conducting. Also discussed herein is a method of producing hydrogen or carbon monoxide comprising: (a) providing an electrochemical reactor having an anode, a cathode, and a membrane between the anode and the cathode, wherein the anode is liquid when the reactor is in operation and wherein the membrane is mixed conducting; (b) introducing a feedstock to the anode; (c) introducing a stream to the cathode, wherein the stream comprises water or carbon dioxide.