Electrochemical Decomposition of CFC12 Using Gas Diffusion Electrodes

Environmental Science & Technology - ENVIRON SCI TECHNOL 01/1998; 32(3):375-378. DOI: 10.1021/es970417d

ABSTRACT Chlorofluorocarbons (CFCs) were known to cause the depletion of the ozone layer at the stratosphere. A large amount of CFCs is still in use as a refrigerant or still present in the plastic forms. These CFCs should be collected and retreated to harmless compounds to the environment. Electrochemical decomposition of dichlorodifluoromethane (CFC-12) was carried out using 12 kinds of metal-supported gas diffusion electrodes (GDEs). Ag-, Cu-, In-, and Pb-supported GDEs showed high electrocatalytic activity of decomposition of CFC-12. Especially Cu-, In-, and Pb-supported GDEs showed almost 100% efficiency without producing the byproduct (H2). Zn-, Ag-, Cu-, and In-supported GDEs caused defluorination of CFC-12 as well as dechlorination and produced methane mainly. Pb-supported GDE induced only dechlorination of CFC-12 and produced difluoromethane (HFC-32) in high selectivity (92.6%). With the increase in the current density, the partial current density of methane formation at Cu-supported GDE was saturated at 370 mA cm-2. The partial current density of HFC-32 formation at Pb-supported GDE was not saturated even at 650 mA cm-2 and kept high selectivity of HFC-32 formation.



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