Direct OC-CHO coupling towards highly C 2+ products selective electroreduction over stable Cu 0 /Cu 2+ interface.

Electroreduction of CO 2 to valuable multicarbon (C 2+ ) products is a highly attractive way to utilize and divert emitted CO 2 . However, a major fraction of C 2+ selectivity is confined to less than 90% by the difficulty of coupling C-C bonds efficiently. Herein, we identify the stable Cu 0 /Cu 2+ interfaces derived from copper phosphate-based (CuPO) electrocatalysts, which can facilitate C 2+ production with a low-energy pathway of OC-CHO coupling verified by in situ spectra studies and theoretical calculations. The CuPO precatalyst shows a high Faradaic efficiency (FE) of 69.7% towards C 2 H 4 in an H-cell, and exhibits a significant FE C2+ of 90.9% under industrially relevant current density (j = -350 mA cm -2 ) in a flow cell configuration. The stable Cu 0 /Cu 2+ interface breaks new ground for the structural design of electrocatalysts and the construction of synergistic active sites to improve the activity and selectivity of valuable C 2+ products.