Diamond decorated with copper nanoparticles for electrochemical reduction of carbon dioxide.

Electrochemical CO2 reduction has been investigated on a planar diamond electrode in aqueous and nonaqueous solutions. On a diamond electrode decorated with copper nanoparticles, CO2 reduction starts from -0.1 V versus a normal hydrogen electrode (NHE) when a mixture of water and ionic liquid ([H2O] = 10 μM) is used. The current density reaches 5.1 ± 0.1 mA cm(-2) for CO2 reduction at a potential of -1.3 V versus NHE. The main products are formic acid and formaldehyde. Moreover, the electrode system is stable and has a long lifetime. It is thus promising to be applied in the future for mass production of industrial chemicals and liquid fuels using CO2 as the source of raw material.