Atomic high-spin cobalt(II) center for highly selective electrochemical CO reduction to CH3OH

• Published in: Nature communications Vol. 14; no. 1; p. 6550
• Main Authors: Ding, Jie, Wei, Zhiming, Li, Fuhua, Zhang, Jincheng, Zhang, Qiao, Zhou, Jing, Wang, Weijue, Liu, Yuhang, Zhang, Zhen, Su, Xiaozhi, Yang, Runze, Liu, Wei, Su, Chenliang, Yang, Hong Bin, Huang, Yanqiang, Zhai, Yueming, Liu, Bin
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 17-10-2023; Nature Publishing Group; Nature Portfolio
• Subjects: 140/131; 140/146; 140/58; 147/28; 639/301/299/886; 639/638/161/886; 639/638/77; 639/766/94; Absorption spectroscopy; Bonding strength; Carbon dioxide; Carbon monoxide; Catalysts; Chemical reduction; Cobalt; Conformation; Density functional theory; Electrochemistry; Electron spin; Feeding rates; Humanities and Social Sciences; Hydrogenation; Infrared absorption; Infrared spectroscopy; Intermediates; Isotope effect; Methanol; Molecular conformation; multidisciplinary; Population density; Population studies; Science; Science (multidisciplinary)
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-023-42307-1

In this work, via engineering the conformation of cobalt active center in cobalt phthalocyanine molecular catalyst, the catalytic efficiency of electrochemical carbon monoxide reduction to methanol can be dramatically tuned. Based on a collection of experimental investigations and density functional theory calculations, it reveals that the electron rearrangement of the Co 3d orbitals of cobalt phthalocyanine from the low-spin state (S = 1/2) to the high-spin state (S = 3/2), induced by molecular conformation change, is responsible for the greatly enhanced CO reduction reaction performance.
Operando
attenuated total reflectance surface-enhanced infrared absorption spectroscopy measurements disclose accelerated hydrogenation of CORR intermediates, and kinetic isotope effect validates expedited proton-feeding rate over cobalt phthalocyanine with high-spin state. Further natural population analysis and density functional theory calculations demonstrate that the high spin Co
2+
can enhance the electron backdonation via the
d
xz
/
d
yz
−2π* bond and weaken the C-O bonding in *CO, promoting hydrogenation of CORR intermediates.
Molecular catalysts provide an ideal model system to investigate the relationship between active site structure and catalytic performance. Here, the authors explore how electrochemical CO reduction to methanol can be controlled through modification of the active cobalt site in cobalt phthalocyanine.