Abstract: Hydrogen and Oxygen are produced by photoelectrically-induced electrolysis wherein solar and/or laser light is passed through a thin layer of a water-caustic soda solution to ionize the solution adjacent an anode. A cathode spaced from the anode and connected thereto by a diode circuit, including a resistance, is used to prevent current flow between the anode and cathode until the potential therebetween exceeds a threshold two volts and preferably 2.4 volts. Upon sufficient ionization in the thin layer of solution, the potential between the anode and cathode exceeds the threshold and current flows therebetween, causing hydrogen gas to form at the cathode. Circulation of the solution between the anode and cathode is caused by convection due to heating of the fluid with solar or laser light.