Unveiling the Synergistic Effect between Graphitic Carbon Nitride and Cu2O toward CO2Electroreduction to C2H4

Abstract Electrochemically 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, a graphitic carbon nitride (g‐C 3 N 4 )‐supported Cu 2 O composite was fabricated, which exhibited 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. reversible hydrogen electrode in 0.1 m KHCO 3 electrolyte. The introduction of g‐C 3 N 4 support not only enhanced the uniform dispersion of Cu 2 O nanocubes, but also stabilized the important *CO intermediates. Moreover, the g‐C 3 N 4 itself had a good activity of reducing CO 2 to form *CO, which enriched the key intermediates of C−C coupling around cuprous oxide. The 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.