Charge‐switchable ligand ameliorated cobalt polyphthalocyanine polymers for high‐current‐density electrocatalytic CO2 reduction
Xin Kong,
Bin Liu,
Zhongqiu Tong,
Rui Bao,
Jianhong Yi,
Shuyu Bu,
Yunpeng Liu,
Pengfei Wang,
Chun‐Sing Lee,
Wenjun Zhang
Affiliations
Xin Kong
State Key Laboratory of Chemical Resource Engineering, College of Chemistry Beijing University of Chemical Technology Beijing China
Bin Liu
State Key Laboratory of Chemical Resource Engineering, College of Chemistry Beijing University of Chemical Technology Beijing China
Zhongqiu Tong
Department of Materials Science and Engineering, Center of Super‐Diamond and Advanced Films (COSDAF) City University of Hong Kong Hong Kong China
Rui Bao
Department of Materials Science and Engineering Kunming University of Science and Technology Kunming China
Jianhong Yi
Department of Materials Science and Engineering Kunming University of Science and Technology Kunming China
Shuyu Bu
Department of Materials Science and Engineering, Center of Super‐Diamond and Advanced Films (COSDAF) City University of Hong Kong Hong Kong China
Yunpeng Liu
Institute of High Energy Physics Chinese Academy of Sciences Beijing China
Pengfei Wang
Key Laboratory of Photochemical Conversion and Optoelectronic Materials Technical Institute of Physics and Chemistry, Chinese Academy of Sciences Beijing China
Chun‐Sing Lee
Department of Materials Science and Engineering, Center of Super‐Diamond and Advanced Films (COSDAF) City University of Hong Kong Hong Kong China
Wenjun Zhang
Department of Materials Science and Engineering, Center of Super‐Diamond and Advanced Films (COSDAF) City University of Hong Kong Hong Kong China
Abstract Metallic phthalocyanines are promising electrocatalysts for CO2 reduction reaction (CO2RR). However, their catalytic activity and stability (especially under high potential) are still unsatisfactory. Herein, we synthesized a covalent organic polymer (COP‐CoPc) by introducing charge‐switchable viologen ligands into cobalt phthalocyanine (CoPc). The COP‐CoPc exhibits great activity for CO2RR, including a high Faradaic efficiency over a wide potential window and the highest CO partial current density among all ligand‐tuned phthalocyanine catalysts reported in the H‐type cell. Particularly, COP‐CoPc also shows great potential for practical applications, for example, a FECO of >95% is realized at a large current density of 150 mA/cm2 in a two‐electrode membrane electrode assembly reactor. Ex situ and in situ X‐ray absorption fine structure spectroscopy measurements and theory calculations reveal that when the charge‐switchable viologen ligands switch to neutral‐state ones, they can act as electron donors to enrich the electron density of Co centers in COP‐CoPc and enhance the desorption of *CO, thus improving the CO selectivity. Moreover, the excellent reversible redox capability of viologen ligands and the increased Co–N bonding strength in the Co–N4 sites enable COP‐CoPc to possess outstanding stability under elevated potentials and currents, enriching the knowledge of charge‐switchable ligands tailored CO2RR performance.
