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A Planar,Conjugated N4-Macrocyclic Cobalt Complex for Heterogeneous Electrocatalytic CO2 Reduction with High Activity |
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| Authors: | Dr Libo Sun Dr Zhenfeng Huang Vikas Reddu Prof Tan Su Prof Adrian C Fisher Prof Xin Wang |
| Institution: | 1. School of Chemical and Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive, Singapore, 637459 Singapore
Cambridge CARES, CREATE Tower, Singapore, 138602 Singapore;2. School of Chemical and Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive, Singapore, 637459 Singapore;3. Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun, 130012 P. R. China;4. Cambridge CARES, CREATE Tower, Singapore, 138602 Singapore Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, CB2 3RA UK |
| Abstract: | Metal complexes have been widely investigated as promising electrocatalysts for CO2 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 N4-macrocyclic cobalt complex (Co(II)CPY) derived from phenanthroline subunits is prepared herein, and it delivers high activity for heterogeneous CO2 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. |
| Keywords: | CO2 reduction cobalt electrocatalysis heterogeneous catalysis macrocycles |