Enhancement of Visible‐Light‐Driven Hydrogen Evolution Activity of 2D π‐Conjugated Bipyridine‐Based Covalent Organic Frameworks via Post‐Protonation
Lu Dai, Anwang Dong, Xiangjian Meng, Huanyu Liu, Yueting Li, Pengfei Li, Bo Wang
Abstract
Abstract Photocatalytic hydrogen (H 2 ) 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 H 2 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 H 2 evolution. This strategy would provide important guidance for the design of highly efficient organic semiconductor photocatalysts.