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

Electrochemical carbon dioxide (CO 2 ) reduction reaction (CO 2 RR) is an attractive approach to deal with the excessive emission of CO 2 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 (C 2+ ) on Cu-based electrocatalysts. However, Cu-based CO 2 RR electrocatalysts suffer from poor catalytic stability mainly due to the structural degradation and loss of active species under CO 2 RR condition. To date, most reported Cu-based electrocatalysts present stabilities over dozens of hours, which limits the advance of Cu-based electrocatalysts for CO 2 RR. Here, a porous chlorine-doped Cu electrocatalyst is reported and exhibits high C 2+ Faradaic efficiency (FE) of 53.8% at -1.00 V versus reversible hydrogen electrode (V RHE ). Importantly, the catalyst exhibited an outstanding catalytic stability in long-term electrocatalysis over 240 hours. Experimental results show that the chlorine-induced stable cationic Cu 0 -Cu + species and the well-preserved structure with abundant active sites are found to be critical to maintain the high FE of C 2+ in the long-term run of electrochemical CO 2 reduction.