Pause electrolysis for acidic CO2 reduction on 3-dimensional Cu

Abstract

Electrochemical CO₂ reduction reaction (CO₂RR) exhibits remarkable potential in producing valuable chemicals with renewable energy. Operating CO₂RR in acidic media is beneficial to solve the issue of low carbon utilization brought by (bi)carbonate formation at the cathode. Suppressing the competing hydrogen evolution reaction and achieving stable CO₂RR performance remains challenging. Herein, we constructed a 3-dimensional Cu (3D-Cu) gas diffusion electrode (GDE) to achieve efficient C₂H₄ production with a partial current density (j_C2H4) of over 470 mA cm⁻² and a Faradaic efficiency (FE_C2H4) of 40%. With pause electrolysis, the decay rate of the j_C2H4 is only half that of the traditional constant electrolysis. The GDE after constant electrolysis was found to suffer from severe salt formation, leading to the decreased activity and poor stability.