CO₂ Electroreduction by Engineering the Cu₂O/RGO Interphase

In the present investigation, Cu₂O-based composites were successfully prepared through a multistep method where cubic Cu₂O nanoparticles (CU Cu₂O) have been grown on Reduced Graphene Oxide (RGO) nanosheets. The structural and morphological properties of the materials have been studied through a comprehensive characterization, confirming the coexistence of crystalline Cu₂O and RGO. Microscopical imaging revealed the intimate contact between the two materials, affecting the size and the distribution of Cu₂O nanoparticles on the support. The features of the improved morphology strongly affected the electrochemical behavior of the composites, increasing the activity and the faradaic efficiencies towards the electrochemical CO₂ reduction reaction process. CU Cu₂O/RGO 2:1 composite displayed selective CO formation over H₂, with higher currents compared to pristine Cu₂O (−0.34 mA/cm² for Cu₂O and −0.64 mA/cm² for CU Cu₂O/RGO 2:1 at the voltage of −0.8 vs. RHE and in a CO₂ atmosphere) and a faradaic efficiency of 50% at −0.9 V vs. RHE. This composition exhibited significantly higher CO production compared to the pristine materials, indicating a favorable *CO intermediate pathway even at lower voltages. The systematic investigation on the effects of nanostructuration on composition, morphology and catalytic behavior is a valuable solution for the formation of effective interphases for the promotion of catalytic properties providing crucial insights for future catalysts design and applications.