Abstract
Electrochemical 
reduction was investigated on 32 metal electrodes in aqueous 
medium. The current efficiency of 
reduction on Ni, Ag, Pb, and Pd increases significantly with lowering the temperature. The ratio of reduction products are also changed by lowering temperature. Potential dependence of 
and 
on an Hg electrode supports the electron transfer mechanism for 
production. Formation of methane and ethylene is observed on almost all metal electrodes used, although the efficiency is mainly very low except for Cu. A periodic table for 
reduction, which is drawn based on the dependence of reduction products on various metals, suggests the existence of a systematic rule for the electrocatalytic reduction of 
on metal surfaces.