Unveiling the synergistic effect between graphitic carbon nitride and Cu2O toward CO2 electroreduction to C2H4.

Electrochemical reducing carbon dioxide (CO 2 RR) to ethylene is one of the most promising strategies to reduce carbon dioxide emissions and simultaneously produce high value-added chemicals. However, the lack of catalysts with excellent activity and stability limits the large-scale application of this technology. In this work, we fabricated the graphitic carbon nitride (g-C 3 N 4 ) supported Cu 2 O composite which exhibits a 32.2% Faradaic efficiency of C 2 H 4 with a partial current density of -4.3 mA/cm 2 at -1.1 V vs. RHE in 0.1 M KHCO 3 electrolyte. The introduction of g-C 3 N 4 support not only enhances the uniform dispersion of Cu 2 O nanocubes, but also stabilizes the important *CO intermediates. Moreover, the g-C 3 N 4 itself has a good activity of reducing CO 2 to form *CO, which enriches the key intermediates of C-C coupling around cuprous oxide. Our findings highlight the importance of the g-C 3 N 4 support, a unique two-dimensional material, including not only the strong CO 2 adsorption and activation capacity but also its synergistic effect with the cuprous oxide in CO 2 RR selectivity.