Synergistic bulk and surface electric fields in self-assembled perylene-based nanosheets expedite photocatalytic hydrogen evolution

Photocatalytic hydrogen evolution presents a sustainable method for clean energy generation, yet its efficiency remains limited by insufficient charge separation and transfer. Herein, we report a novel strategy to enhance photocatalytic efficiency by integrating both bulk and surface electric fields within self-assembled supramolecular photocatalyst. We synthesized perylene 3,4-dicarboxylic acid (PDA) with a large dipole moment and polar carboxyl groups, which self-assembles into ultrathin 2D nanosheets in water. The accumulation of dipole moments induces a bulk electric field, enabling ultrafast exciton dissociation into free charges. Concurrently, the exposed carboxyl groups generate a surface electric field, facilitating efficient charge extraction and transfer on the surface for proton reduction. The synergistic interplay between bulk and surface electric fields results in an impressive photocatalytic hydrogen production rate of 3.2 mmol g⁻¹ h⁻¹ , significantly surpassing that of the other perylene-based nanosheets relying solely on either bulk or surface electric fields. This study offers valuable insights into the distinct roles of bulk and surface electric fields in photocatalytic processes, and introduces a new design paradigm for photocatalysts to enhance solar-to-hydrogen conversion efficiency.