A radiolytic electrochemical system that comprises a cathode, an anode that comprises a semiconductor, an aqueous electrolyte solution disposed between the cathode and anode, and ionizing radiation, wherein the ionizing radiation splits water molecules and forms solvated free radicals that migrate to the anode or cathode, depending upon a radical's charge, and participate in redox reactions at the anode and cathode thereby producing electrical current capable of performing work when the anode and cathode are electrically connected.