Electron‐Rich Pincer Ligand‐Coupled Cobalt Porphyrin Polymer with Single‐Atom Sites for Efficient (Photo)Electrocatalytic CO<sub>2</sub> Reduction at Ultralow Overpotential
Tingxia Wang, Lulu Guo, Hao Pei, Shengtao Chen, Renjie Li, Jing Zhang, Tianyou Peng
Abstract
Abstract Porphyrin and phthalocyanine complexes bearing single‐atom catalytic sites (M‐N 4 ) have been explored as promising electrocatalysts for CO 2 reduction reaction (CO 2 RR), whose activity can be improved by regulating the ligands and/or the metal centers. Moreover, their photosensitive features also provide the possibility for highly efficient photoelectrocatalytic CO 2 RR. Herein, a novel N′NN′ ‐pincer‐ligand (N 3 )‐coupled cobalt porphyrin (CoPor‐N 3 ) polymer is developed for realizing efficient (photo)electrocatalytic CO 2 RR. The unraveled electronic structure and (photo)electrocatalytic features suggest that a synergistic effect between the electron‐rich N 3 ligands and the Co‐N 4 single‐atom sites in the CoPor‐N 3 polymer results in the Co centers attaining more electrons, which is beneficial to facilitating the electron transfer to CO 2 for the activation and reduction processes. As expected, the resultant CoPor‐N 3 polymer delivers a good long‐term durability and high CO faradaic efficiency (96%) at an ultralow overpotential (0.39 V), which outperforms the CoPor alone and most porphyrin‐/phthalocyanine‐based electrocatalysts reported so far. Moreover, the photosensitivity of CoPor units can further reduce the overpotential to 0.34 V with a CO faradaic efficiency over 90% under light illumination. The present findings offer a new approach to constructing porphyrin‐based photosensitive electrocatalysts with high‐efficiency photoelectrocatalytic CO 2 RR.