Electroreduction of Carbon Dioxide on Copper-Based Electrodes: Activity of Copper Single Crystals and Copper-Gold Alloys

The activity of copper single-crystal and copper-gold alloyed (Au1Cu99, Au10Cu90, Au20Cu80, Au50Cu50) electrodes for CO2 electroreduction has been investigated in aqueous phosphate buffer solutions by cyclic voltammetry and potentiostatic long-term electrolysis. In addition to H-2, four species were identified in the gaseous phase by chromatography after electrolyses: CO, CH4, C2H4 and traces of C2H6. At copper electrodes, the major carbon-containing products are CO and CH4. Analysis of the data indicates that the fraction of methane increases in the order Cu (poly)