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A Planar, Conjugated N 4 ‐Macrocyclic Cobalt Complex for Heterogeneous Electrocatalytic CO 2 Reduction with High Activity
Author(s) -
Sun Libo,
Huang Zhenfeng,
Reddu Vikas,
Su Tan,
Fisher Adrian C.,
Wang Xin
Publication year - 2020
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.202007445
Subject(s) - cobalt , electrocatalyst , chemistry , conjugated system , porphyrin , aqueous solution , faraday efficiency , metal , ligand (biochemistry) , catalysis , combinatorial chemistry , inorganic chemistry , photochemistry , electrochemistry , electrode , organic chemistry , polymer , biochemistry , receptor
Metal complexes have been widely investigated as promising electrocatalysts for CO 2 reduction. Most of the current research efforts focus mainly on ligands based on pyrrole subunits, and the reported activities are still far from satisfactory. A novel planar and conjugated N 4 ‐macrocyclic cobalt complex (Co(II)CPY) derived from phenanthroline subunits is prepared herein, and it delivers high activity for heterogeneous CO 2 electrocatalysis to CO in aqueous media, and outperforms most of the metal complexes reported so far. At a molar loading of 5.93×10 −8 mol cm −2 , it exhibits a Faradaic efficiency of 96 % and a turnover frequency of 9.59 s −1 towards CO at −0.70 V vs. RHE. The unraveling of electronic structural features suggests that a synergistic effect between the ligand and cobalt in Co(II)CPY plays a critical role in boosting its activity. As a result, the free energy difference for the formation of *COOH is lower than that with cobalt porphyrin, thus leading to enhanced CO production.