High photocatalytic hydrogen evolution via strong built-in electric field induced by high molecular dipoles of heteroatom-annulated perylene imide supramolecule

In recent years, PDI-based supramolecular photocatalysts have attracted significant attention. However, charge localization effects hinder the charge transfer in PDI, thereby leading to a high recombination rate and limited activity. Herein, three heteroatom bay -annulated perylene diimide supramolecule photocatalysts (N-APDI, S-APDI and Se-APDI) were developed for photocatalytic H2 evolution. Under visible-light irradiation, heteroatom-annulated PDI supramolecule display better H2 evolution rate than that of APDI without heteroatom, in which N-APDI shows the highest hydrogen production rate of 61.49 mmol g-1 h-1 and an apparent quantum yield (AQY) of 5.90% at 420 nm. The enhancement in photocatalytic activity of heteroatom-annulated PDI supramolecule can be rationalized by stronger molecular dipole, which enhance internal electric field magnitude and thus promotes the separation and migration of charge. Also, heteroatom-annulation heteroatom can act as more beneficial active site to promote HER activity. This work provides a new strategy to develop supramolecular photocatalysts. (c) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

In recent years, PDI-based supramolecular photocatalysts have attracted significant attention. The charge localization effects hinder the charge transfer in PDI, resulting in a high recombination rate and limited activity. This study developed three heteroatom bay-annulated perylene diimide supramolecule photocatalysts (N-APDI, S-APDI, and Se-APDI) for photocatalytic H2 evolution. Under visible-light irradiation, heteroatom-annulated PDI supramolecules exhibited better H2 evolution rate than non-heteroatom APDI, with N-APDI showing the highest hydrogen production rate of 61.49 mmol g-1 h-1 and an apparent quantum yield (AQY) of 5.90% at 420 nm. The improved photocatalytic activity of heteroatom-annulated PDI supramolecules can be attributed to stronger molecular dipole, which enhances the internal electric field magnitude and promotes charge separation and migration. Furthermore, heteroatom annulation can act as a more beneficial active site to promote HER activity. This work provides a new strategy for the development of supramolecular photocatalysts.