Enhancement of Visible‐Light‐Driven Hydrogen Evolution Activity of 2D π‐Conjugated Bipyridine‐Based Covalent Organic Frameworks via Post‐Protonation. (2nd March 2023)

• Record Type: Journal Article
• Authors: Dai, Lu; Dong, Anwang; Meng, Xiangjian; Liu, Huanyu; Li, Yueting; Li, Pengfei; Wang, Bo
• Is Part Of: Angewandte Chemie. Volume 135:Number 15(2023)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2023-03-02
• Subjects: Bipyridine -- COF -- Photocatalytic Hydrogen Evolution -- Protonation -- π-Conjugation; Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.202300224
• Languages: English
• ISSNs: 0044-8249

Abstract

Abstract: Photocatalytic hydrogen (H2 ) evolution represents a promising and sustainable technology. Covalent organic frameworks (COFs)‐based photocatalysts have received growing attention. A 2D fully conjugated ethylene‐linked COF (BTT‐BPy‐COF) was fabricated with a dedicated designed active site. The introduced bipyridine sites enable a facile post‐protonation strategy to fine‐tune the actives sites, which results in a largely improved charge‐separation efficiency and increased hydrophilicity in the pore channels synergically. After modulating the degree of protonation, the optimal BTT‐BPy‐PCOF exhibits a remarkable H2 evolution rate of 15.8 mmol g −1 h −1 under visible light, which surpasses the biphenyl‐based COF 6 times. By using different types of acids, the post‐protonation is proved to be a potential universal strategy for promoting photocatalytic H2 evolution. This strategy would provide important guidance for the design of highly efficient organic semiconductor photocatalysts. Abstract : The introduction of bipyridine motifs in the 2D conjugated covalent organic framework, 2D‐ c ‐COF, creates dedicated photoactive sites. Through a simple post‐protonation strategy, the photo‐generated electron–hole separation of 2D‐ c ‐COF was significantly enhanced and a hydrophilic pore channel was generated, which synergically lead to a significant improvement in photocatalytic hydrogen production.