Residual Chlorine Induced Cationic Active Species on a Porous Copper Electrocatalyst for Highly Stable Electrochemical CO2 Reduction to C2.

Electrochemical carbon dioxide (CO2 ) reduction reaction (CO2 RR) is an attractive approach to deal with the emission of CO2 and to produce valuable fuels and chemicals in a carbon-neutral way. Many efforts have been devoted to boost the activity and selectivity of high-value multicarbon products (C2+ ) on Cu-based electrocatalysts. However, Cu-based CO2 RR electrocatalysts suffer from poor catalytic stability mainly due to the structural degradation and loss of active species under CO2 RR condition. To date, most reported Cu-based electrocatalysts present stabilities over dozens of hours, which limits the advance of Cu-based electrocatalysts for CO2 RR. Herein, a porous chlorine-doped Cu electrocatalyst exhibits high C2+ Faradaic efficiency (FE) of 53.8 % at -1.00 V versus reversible hydrogen electrode (VRHE ). Importantly, the catalyst exhibited an outstanding catalytic stability in long-term electrocatalysis over 240 h. Experimental results show that the chlorine-induced stable cationic Cu0 /Cu+ species and the well-preserved structure with abundant active sites are critical to the high FE of C2+ in the long-term run of electrochemical CO2 reduction.