Pulsed Electroreduction of CO2 on Carbon Fiber Electrodes

摘要

The electrochemical reduction of CO2 has been carried out by pulsed electrolysis primarily on pitch-based andrnPAN-based carbon fibers. The electrolyte consisted of 0.1 mol~(-3) dm~(-3) KHCO_3, and 12×10~(-4) mol dm~(-3) CuSO4_, whichrnwas used for electroplating on carbon for production of CH4 and C_2H_4. The highest current efficiencies of C_2H_4rnand CH4 were obtained by pitch-based carbon fiber. On the other hand, the current efficiency of C_2H_4 or CH4 wasrnalmost zero for the activated carbon fiber made of cellulose, although copper was electroplated on the fiber. Thernproduction of hydrocarbons such as C_2H_4 and CH_4 is strongly dependent upon the graphitiability of carbon fiber.rnAfter electrolysis of successive four runs, at cathodic potential of –2.1 V vs. Ag/AgCl and anodic potential of 0.7 Vrnvs. Ag/AgCl, it was found that intensity of D-band Raman line increased without the increase in half-width. Fromrnthe characteristics of carbon electrode by Raman spectroscopy before and after electrochemical reduction of CO_2,rnthe production of C_2H_4 seemed to do with the edge sites of carbon.