On the electrocatalytic reduction of CO2 using Cu-nanoparticles decorating Au electrode.

CO₂ is electrocatalytically reduced in aqueous solutions (NaHCO₃ and Na₂SO₄ ) at polycrystalline gold (Au) both bare and modified with copper nanoparticles (nano-Cu) (nano-Cu/Au). Copper nanoparticles were deposited by the cycling of potential in the range (–0.2–0.7 V) for various potential cycles. The effect of the electrolyte, as well as the nano-Cu loading on the electroreduction of CO₂, has been investigated. Nano-Cu/Au electrode has been voltammetrically and morphologically characterized. It has been found that the type of electrolyte, that is, NaHCO₃ and Na₂SO₄, is critical in the electrochemical reduction of CO₂ ; for instance, the CO₂ reduction is obscured by hydrogen evolution in NaHCO₃ solutions (pH 9.2) at both electrodes, that is, bare Au and nano-Cu/Au electrodes, the well-defined redox peak is obtained at both electrodes in Na₂SO₄ solution (pH 7), even though the pH of Na₂SO₄ is smaller. The extent of catalysis is based on the copper loading at the nano-Cu/Au electrode as well. [ABSTRACT FROM AUTHOR]