Hybridization of covalent organic frameworks and photosensitive metal‐organic rings: A new strategy for constructing supramolecular Z‐scheme heterostructures for ultrahigh photocatalytic hydrogen evolution
Xinao Li, Zi‐Zhan Liang, Yecheng Zhou, Jianfeng Huang, Xiaolin Wang, Limin Xiao, Jun‐Min Liu
Abstract
Abstract The rational design of Z‐scheme heterojunction photosystems based on covalent organic frameworks (COFs) is a promising strategy for harnessing solar energy for hydrogen conversion. Herein, a direct Z‐scheme single‐atom photocatalyst based on COF and metal‐organic ring has been constructed through the supramolecular interactions of coral‐like COF (S‐COF) and photosensitized Pd 2 L 2 type metal‐organic ring (MAC‐FA1). The MAC‐FA1/S‐COF heterojunction exhibits good light absorption, efficient charge separation and transfer, slow electron‐hole recombination, and highly dispersed Pd active sites, enabling an efficient and stable H 2 evolution reaction. The optimized 4% MAC‐FA1/S‐COF achieves an H 2 evolution rate of 100 mmol g −1 h −1 within 5 h and obtains a total accumulated turn‐over number relative to Pd (TON Pd ) of 437,685 within 20 h, far superior to S‐COF, MAC‐FA1, M‐5/S‐COF, Pd/S‐COF, and M‐5/Pd/S‐COF, which is one of the highest records among COF‐based photocatalysts for solar‐driven H 2 evolution. This is the first work to incorporate photosensitized metal‐organic rings/cages into porous crystalline COFs to form a supramolecular Z‐scheme heterojunction, which has significant potential as a high‐performance photocatalyst for solar‐driven H 2 production.