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

Abstract

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.