Residual Chlorine Induced Cationic Active Species on a Porous Copper Electrocatalyst for Highly Stable Electrochemical CO 2 Reduction to C 2

Electrochemical carbon dioxide (CO ) reduction reaction (CO RR) is an attractive approach to deal with the emission of CO 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 ) on Cu-based electrocatalysts. However, Cu-based CO RR electrocatalysts suffer from poor catalytic stability mainly due to the structural degradation and loss of active species under CO 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 RR. Herein, a porous chlorine-doped Cu electrocatalyst exhibits high C Faradaic efficiency (FE) of 53.8 % at -1.00 V versus reversible hydrogen electrode (V ). Importantly, the catalyst exhibited an outstanding catalytic stability in long-term electrocatalysis over 240 h. Experimental results show that the chlorine-induced stable cationic Cu /Cu species and the well-preserved structure with abundant active sites are critical to the high FE of C in the long-term run of electrochemical CO reduction.