Modulating the Band Structure of Metal Coordinated Salen COFs and an In Situ Constructed Charge Transfer Heterostructure for Electrocatalysis Hydrogen Evolution

• Published in: Advanced science 2022-08, Vol.9 (22), p.e2105912-n/a
• Main Authors: Zhang, Boying, Chen, Liling, Zhang, Zhenni, Li, Qing, Khangale, Phathutshedzo, Hildebrandt, Diane, Liu, Xinying, Feng, Qingliang, Qiao, Shanlin
• Format: Article
• Language: English
• Subjects: Alternative energy; band structure modulation; Carbon; Chemistry; heterostructures; High temperature; Hydrogen; hydrogen evolution reaction; in situ solid‐state polymerization; Ligands; NMR; Nuclear magnetic resonance; Salen covalent organic frameworks (COFs); Single crystals
• ISSN: 2198-3844; 2198-3844
• DOI: 10.1002/advs.202105912

A series of crystalline, stable Metal (Metal = Zn, Cu, Ni, Co, Fe, and Mn)‐Salen covalent organic framework (COF)EDA complex are prepared to continuously tune the band structure of Metal‐Salen COFEDA, with the purpose of optimizing the free energy intermediate species during the hydrogen evolution reaction (HER) process. The conductive macromolecular poly(3,4‐ethylenedioxythiophene) (PEDOT) is subsequently integrated into the one‐dimensional (1D) channel arrays of Metal‐Salen COFEDA to form heterostructure PEDOT@Metal‐Salen COFEDA via the in situ solid‐state polymerization method. Among the Metal‐Salen COFEDA and PEDOT@Metal‐Salen COFEDA complexes, the optimized PEDOT@Mn‐Salen COFEDA displays prominent electrochemical activity with an overpotential of 150 mV and a Tafel slope of 43 mV dec−1. The experimental results and density of states data show that the continuous energy band structure modulation in Metal‐Salen COFEDA has the ability to make the metal d‐orbital interact better with the s‐orbital of H, which is conducive to electron transport in the HER process. Moreover, the calculated charge density difference indicates that the heterostructures composed of PEDOT and Metal‐Salen COFEDA induce an intramolecular charge transfer and construct highly active interfacial sites. The conductive macromolecule cables are subsequently integrated into the one‐dimensional (1D) channels of a series of crystalline Metal‐Salen covalent organic frameworks (COFs) (Metal = Zn, Cu, Ni, Co, Fe, and Mn) to form heterogenous poly(3,4‐ethylenedioxythiophene)@Metal‐Salen COFEDA complexes via the in situ solid‐state polymerization method, in order to improve the electrochemical activity of hydrogen evolution reaction.