CuNCN derived Cu-based/CxNy catalysts for highly selective CO2 electroreduction to hydrocarbons

Copper (Cu) has been proved as an efficient catalyst in carbon dioxide electrochemical reduction reaction (CO 2 RR) 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 C 2 H 4 Faradaic efficiency of 48.5% at 500 mA cm - 2 . However, increasing the pyrolysis temperature above 400 °C gives rise to CH 4 being the predominant product and CuNCN-500 achieves CH 4 Faradaic efficiencies of 66.3% at 300 mA cm - 2 . Combining experimental and DFT calculation results, Cu 3 N plays a crucial role in the formation of C 2 H 4 , 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-C 3 N 4 and different Cu species for achieving the desired selectivity during CO 2 RR.