Copper (Cu) has been proved as an efficient catalyst in carbon dioxide electrochemical reduction reaction (CO₂RR) towards hydrocarbons, but still suffers from low selectivity and poor stability. Herein, Cu-based/CxNy catalysts were fabricated by facile pyrolysis of CuNCN in sealed quartz tubes. It is found that CuNCN pyrolyzed at 300 °C (CuNCN-300) exhibits a high C₂H₄ Faradaic efficiency of 48.5% at 500 mA cm^-2. However, increasing the pyrolysis temperature above 400 °C gives rise to CH₄ being the predominant product and CuNCN-500 achieves CH₄ Faradaic efficiencies of 66.3% at 300 mA cm^-2. Combining experimental and DFT calculation results, Cu₃N plays a crucial role in the formation of C₂H₄, while tri-s-triazine units in CuNCN-500 reduce the barrier of *CO hydrogenation to *CHO and retard C-C coupling on Cu surface. These findings mark the significance of precise tailoring of the synergistic effect between g-C₃N₄ and different Cu species for achieving the desired selectivity during CO₂RR.

铜（Cu）已被证明是二氧化碳电化学还原反应（CO ₂ RR）对碳氢化合物的有效催化剂，但仍存在选择性低、稳定性差的问题。在此，Cu 基/CxNy 催化剂是通过在密封石英管中简单地热解 CuNCN 来制造的。发现在 300 °C 热解的 CuNCN (CuNCN-300)在 500 mA cm ^{- 2下表现出 48.5% 的高 C} ₂ H ₄法拉第效率。然而，将热解温度提高到 400 °C 以上会导致 CH ₄成为主要产物，并且 CuNCN-500在 300 mA cm ^{- 2下实现了 66.3% 的 CH} _{4法拉第效率}. 结合实验和DFT计算结果，Cu _{3 N在C 2} H ₄的形成中起着至关重要的作用，而CuNCN-500中的三-s-三嗪单元降低了*CO氢化成*CHO的势垒，并延缓了Cu上的CC偶联。表面。这些发现标志着精确调整gC ₃ N _{4和不同Cu 物种之间的协同效应对于在CO 2} RR期间实现所需选择性的重要性。