Polyimide with enhanced π stacking for efficient visible-light-driven photocatalysis

Abstract

Polyimide organic semiconductors have received considerable attention as chemically stable donor–acceptor photocatalysts, yet exhibit moderate photocatalytic efficiency which is limited by low surface area, insufficient light harvesting capability, and rapid recombination of photo-excited charge carriers. Herein, we develop a polyimide-based photocatalyst with a significantly enhanced π stacking structure which is obtained from solvothermal condensation of pyromellitic dianhydride and N,N-diethylmelamine. The ordered π stacking leads to extended light absorption ranges via effective intermolecular π–π interactions, resulting in a high hydrogen evolution rate of 2516 μmol g⁻¹ h⁻¹ with an apparent quantum efficiency of 11% at 420 nm, as well as significantly boosted photocatalytic degradation and H₂O₂ synthesis activities.