Tuning d‐Band Structure of CuII in Coordinated Polymer via d–π Conjugation for Improving CO2 Electroreduction Selectivity toward C2 Products

Abstract Copper‐coordinated catalysts are reported to be effective for electrocatalytic CO 2 reduction reaction (CO 2 RR) to C 2 products but suffer from low selectivity. Herein a strategy was developed to tune the d‐band structure of Cu II via coordinating with aromatic ligands to form Cu‐based conjugated polymers for CO 2 RR to C 2 chemicals. The catalysts derived from copper chloride coordinating with tetraminobenzoquinone (TABQ) and with 1,2,4,5‐benzenetetramine possessed high‐density and compact Cu single‐atom sites and displayed high activity for CO 2 RR to C 2 products. Especially, Cu‐TABQ exhibited a maximum C 2 faradaic efficiency of 63.2 % with a current density of 423 mA cm −2 at −1.17 V (vs. reversible hydrogen electrode). Density functional theory calculations indicated that the TABQ linker possessing C=O groups significantly widened the d‐band of coordinated Cu II , which facilitated binding of *CO intermediate on the catalyst and thus enhanced C−C coupling. This work provides mechanistic insight into the Cu II ‐coordinated polymers for CO 2 RR with high selectivity toward C 2 products.