Pulsed electroreduction of carbon dioxide was performed on Cu electrod
es. The formation rates of reduction products of CO2 showed strong con
trast between the pulsed method and conventional (galvanostatic) metho
d. Namely, the faradaic efficiencies of CH4 and C2H4 under the pulsed
condition kept constant while those under the steady-state electroredu
ction reduced drastically as the reduction time passed. This is ascrib
ed to the difference in surface properties of the electrode under the
pulsed and steady-state conditions. It is pointed out that, for a long
-term electroreduction in which the poisoning of the electrode activit
y due to the deposition of reaction products is likely to take place,
the pulsed method is superior to the conventional one.