Insight into the Molecular Mechanism for Enhanced Longevity of Supramolecular Vesicular Photocatalysts
Yannan Liu, Fulu Zheng, Haojie Dai, Chuanshuang Chen, Yajing Chen, Haolin Wu, Chunyang Yu, Yiyong Mai, Thomas Frauenheim, Yongfeng Zhou
Abstract
Supramolecular self-assembly is a promising strategy for stabilizing the photo-sensitive components in photocatalysis. However, the underlying correlation between the enhanced photostability and supramolecular structure at the molecular level has not yet been fully understood. Herein, we develop a biomimetic vesicular membrane-based polyporphyrin photocatalyst exhibiting excellent photocatalytic stability with at least activity time of 240 h in hydrogen generation. Time-domain ab initio modelling together with transient absorption spectroscopy, visual frontier orbitals and Gibbs free energy calculation disclose that the ordered aggregation of porphyrin units in the vesicle membrane facilitates "hot" electron relaxation and the rapid dissipation of photo-generated charges, thereby contributing to the longevity. This work deepens the molecular-level understanding on photostability and photocatalytic mechanism of supramolecular photocatalysts.