Joint Study on the Photochemical and Catalytic Conversion of the Gases Causing the Rise in Earth's Temperature and the Decomposition of Ozone Layr to Innocuouc Species

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As pointed out, the conversion of the gases causing the rise in earth's temperature and the decomposition of ozone layr to innocuous species is a pressing and important subject. Taking thought for energy situation of advanced countries and the economical stuation of underdeveloped countries, it is almost imposible to control the discharge of these noxious gases by law. Accordingly, in the present study, a photocatalytic and/or a electrocatalytic processes to convert these gases to innocuous spesies, which can take place under low input energy, has been developed.The electrochemical conversion of CO_2 to more complex compounds is assumed to be promising since this reaction occurs at room temperature and has the possibility of being developed into a process similar to photosynthesis. However, a fault of this technique is requirement of a highly negative overpotential. In order to mitigate the overpotential required for the reduction of CO_2, we have developed the electrocatalytic process at the modified electrode having two laminated films consisting of an inorganic conductor and a conducting polymer such as Prussian blue and polyaniline, respectively. This electrode gave the reduction products involving formic and lactic acids at a much lower overpotential than that hitherto acieved.Chlorofluorocarbon (CFC-113), CHCl_3 and CCl_4 have been photolysed in the presence of H_2O,and the decomposed species scavenged by the reaction with a metal powder. The decomposition of these hazardous compounds was almost 100%. All chlorine atoms were fixed in the form of metal chloride, and no gaseous product existed except CO_2. The scavenging reaction of generated reactive species was brought about by the oxidation of the metal, and hence divalent and trivalent metal compounds showed only insignificant scavenging efficiency.