Modulating Photoinduced Electron Transfer between Photosensitive MOF and Co(II) Proton Reduction Sites for Boosting Photocatalytic Hydrogen Production

• Published in: Small (Weinheim an der Bergstrasse, Germany) Vol. 19; no. 48; pp. e2305024 - n/a
• Main Authors: Bai, Jianguo, Wang, Jun, Zheng, Hao, Zhao, Xiaoli, Wu, Pengyan, Pei, Li, Wang, Jian
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 01.11.2023
• Subjects: Charge efficiency; Cobalt compounds; Electron transfer; Hydrogen evolution; Hydrogen production; intermolecular; intramolecular; Metal-organic frameworks; Photocatalysis; photocatalytic hydrogen production; photoinduced electron transfer; Photosensitivity; Protons; Water splitting; Zinc; intermolecular; photoinduced electron transfer; intramolecular; metal-organic frameworks; photocatalytic hydrogen production
• ISSN: 1613-6810; 1613-6829; 1613-6829
• DOI: 10.1002/smll.202305024

Photocatalytic hydrogen production via water splitting is the subject of intense research. Photoinduced electron transfer (PET) between a photosensitizer (PS) and a proton reduction catalyst is a prerequisite step and crucial to affecting hydrogen production efficiency. Herein, three photoactive metal–organic framework (MOF) systems having two different PET processes where PS and Co(II) centers are either covalently bonded or coexisting to drive photocatalytic H2 production are built. Compared to these two intramolecular PET systems including CoII‐Zn‐PDTP prepared from the post‐synthetic metalation toward uncoordinated pyridine N sites of Zn‐PDTP and sole cobalt‐based MOF Co‐PDTP, the CoII(bpy)3@Zn‐PDTP system impregnated by molecular cocatalyst possessing intermolecular PET process achieves the highest H2 evolution rate of 116.8 mmol g−1 h−1 over a period of 10 h, about 7.5 and 9.3 times compared to CoII‐Zn‐PDTP and Co‐PDTP in visible‐light‐driven H2 evolution, respectively. Further studies reveal that the enhanced photoactivity in CoII(bpy)3@Zn‐PDTP can be ascribed to the high charge‐separation efficiency of Zn‐PDTP and the synergistic intermolecular interaction between Zn‐PDTP and cobalt complexes. The present work demonstrates that the rational design of PET process between MOFs and catalytic metal sites can be a viable strategy for the development of highly efficient photocatalysts with enhanced photocatalytic activities. Three photoactive metal–organic framework systems having two different photoinduced electron transfer (PET) processes to drive photocatalytic H2 production are reported, wherein, CoII(bpy)3@Zn‐PDTP system using [Co(bpy)3]Cl2 as a cocatalyst with the intermolecular PET process extremely enhances the photocatalytic activity to 7.5 and 9.3 times the value afforded by CoII‐Zn‐PDTP system and bare Co‐PDTP, respectively.