Electrochemical Reduction of CO 2 at Sb and Bi Electrodes in KHCO 3 Solution

Abstract

Electrochem. redn. of CO2 in KHCO3 solns. was studied by using differently prepd. Sb and Bi electrodes. With Sb plated electrodes, H2 was produced mainly with a small amt. of HCOOH, i.e., Sb was not effective for CO2 redn. With Bi electrodes, HCOOH was produced in high current efficiencies with a trace amt. of CO. The current efficiency and the rate for HCOOH formation were largely improved by the use of Bi-plated electrodes, and they were dependent on the kind of electrode substrates on which Bi was plated. The utility of a Bi-plated glassy C electrode gave HCOOH at .apprx.100% current efficiency at potentials of -1.4 to -1.7 vs. SCE at a prodn. rate of .apprx.1 A/dm2. The current efficiency is dependent on the purity of the electrode surface and the particle size of Bi plated rather than the roughness factor of the electrode surface. [on SciFinder (R)]