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Electrochemical Hydrogenation of CFC-12 at Metal-Phthalocyanine Supported Gas-Diffusion Electrodes

2002; Institute of Physics; Volume: 149; Issue: 11 Linguagem: Inglês

10.1149/1.1514646

1945-7111

Noriyuki Sonoyama, Hideki Fujii, Tadayoshi Sakata,

Catalytic Processes in Materials Science

Electrochemical hydrogenation of (CFC-12) using metal-phthalocyanine (metal-PC) supported gas diffusion electrodes (GDEs) has been carried out. The electrocatalytic activity for hydrogenation of CFC-12 depends on the metal center of metal-PCs that are supported on GDEs as the electrocatalyst. Cu-phthalocyanine (PC) supported GDE provides high activity and Zn-, Co-, Pd-, and Ni-PC supported GDEs show moderate activity, whereas the Fe- and free-base PC-supported GDEs have low activity. The main products were also dependent on the metal center of metal-PCs: methane at the Co-PC supported GDE, methane and difluoromethane at the Zn-PC supported GDE, difluoromethane at the Pd-PC supported GDE, and chlorodifluoromethane at the Co- and Ni-PC supported GDEs. From the potential dependence of current efficiency for the product formation at metal-PC supported GDEs and the absorption spectra change of metal-PCs dissolved in dimethylformamide during electrolysis under CFC-12, it is suggested that each metal center of metal-PCs acts as an adsorption site for CFC-12, and adsorbed CFC-12 is reduced by the two-electron reduced PC ring. © 2002 The Electrochemical Society. All rights reserved.