Unprecedented Lower Over-potential for CO2 Electro-reduction on Copper oxide Anchored to Graphene Oxide Microstructures

Abstract

Efficient conversion of CO2 into chemical feedstock and fuels via electrochemical carbon dioxide reduction reaction (ECO2R) has perpetuated ambitious and broad research interests. Herein, we report the design and synthesis of copper oxide anchored to graphene oxide (Cu/CuxO.GO) porous microstructures via a simple and atom-economical DC electrophoresis approach that exhibit excellent electro-catalytic activity toward ECO2R. A systematic rationalisation of the several physico-chemical parameters associated with the fabrication of porous Cu/CuxO.GO network, viz. composition, the extent of defects in GO and the proportion of oxide contents in Cu/CuxO was explored to understand their impact on the electro-catalytic activity of copper plus GO-based composites. The porous and asymmetric Cu/CuxO.GO nano-composite with optimised oxide content, and metal-GO interactions exhibit an excellent activity for CO2 electroreduction into CO and ethane with a respective Faradaic efficiency (F.E.) of ca. 40% and 4% at an applied potential of just -0.28 V (vs NHE) in a CO2 saturated acetonitrile solution. Comparison of the overpotential specific F.E. values with the ones reported for similar investigations suggests that the electro-catalytic performance of the Cu/CuxO.GO network is significantly better than that observed for various state of the art electro-catalysts recently designed for the ECO2R.