Ultrafast Charge Transfer Dynamics in 2D Covalent Organic Frameworks/Re-Complex Hybrid Photocatalyst

Published: 2022
Nature Communications,13(845)


Rhenium(I)-carbonyl-diimine complexes have emerged as promising photocatalysts for carbon dioxide reduction with covalent organic frameworks recognized as perfect sensitizers and scaffold support. Such Re complexes/covalent organic frameworks hybrid catalysts have demonstrated high carbon dioxide reduction activities but with strong excitation energy-dependence. In this paper, we rationalize this behavior by the excitation energy-dependent pathways of internal photo-induced charge transfer studied via transient optical spectroscopies and time-dependent density-functional theory calculation. Under band-edge excitation, the excited electrons are quickly injected from covalent organic frameworks moiety into catalytic RheniumI center within picosecond but followed by fast backward geminate recombination. While under excitation with high-energy photon, the injected electrons are located at high-energy levels in RheniumI centers with longer lifetime. Besides those injected electrons to RheniumI center, there still remain some long-lived electrons in covalent organic frameworks moiety which is transferred back from RheniumI. This facilitates the two-electron reaction of carbon dioxide conversion to carbon monoxide.

Quinying Pan
Mohamed Abdellah
Yuehan Cao
Weihua Lin
Yang Liu
Jie Meng
Quan Zhou
Qian Zhao
Xiaomei Yan
Zonglong Li
Hao Cui
Huili Cao
Wenting Fang
David Ackland Tanner
Mahmoud Abdel-Hafiez
Ying Zhou
Tonu Pullerits
Sophie E. Canton
Hong Xu
Kaibo Zheng