Reduction of CO/sub 2/ to methanol and methane by photo and dark reactions on semiconductor electrodes. Annual report, February 15, 1984-February 15, 1985

This report investigates the electrochemical mechanism of reduction of CO/sub 2/ or carbonate species to useful fuels using semiconductor and metal electrodes. The semiconductor electrodes may be used to convert light and CO/sub 2/ into fuels such as methanol and methane. Metal electrodes could be coupled to photovoltaic arrays for solar energy storage via fuel generation. Carbon dioxide is an abundant raw material that may be used as a source of inorganic carbon. By suitable electrochemical processes this inorganic carbon may be converted to organic carbon in the form of methanol and methane, which could be used as fuel. Such electrochemical conversions can be made to occur at semiconductor electrodes. In addition, semiconductor electrodes absorb light, and this light can be converted to a voltage that causes the electrochemical transformations of interest. By combining the CO/sub 2/, water, semiconductor, and sunlight, the authors can store solar energy in the fuel. The end result is a method to upgrade the products of ordinary combustion, namely CO/sub 2/ and H/sub 2/O, by returning them to useful fuels. This research program consists of a study of the electrochemical and solid state aspects of the conversion of CO/sub 2/ to fuels at semiconductor andmore » metal electrodes.« less