Polydopamine-Mediated Interfacial Engineering of Perylene Diimide Organic Semiconductors for Photocatalytic Hydrogen Evolution.

Efficient and durable hydrogen evolution with PDI-based organic supramolecular photocatalysts remains limited by insufficient surface-active sites, structural instability and inefficient charge utilization. Here, we design a bioinspired polydopamine (PDA)-mediated interface to construct a PDA-coated PDI-COOH (PDI-COOH@PDA) photocatalyst. The optimized Pt/PDI-COOH@PDA achieves a hydrogen evolution rate of 18.8 mmol g-1 h-1 and an apparent quantum yield (AQY) of 2.1% at 420 nm, representing a 3.5-fold enhancement over Pt/PDI-COOH. Rather than acting as a passive coating, PDA functions as an active interfacial regulator by creating a favorable interfacial reaction microenvironment, anchoring the Pt cocatalyst, and stabilizing the supramolecular framework. The hydrophilic PDA surface promotes water enrichment, while PDA-induced interfacial polarization regulates photogenerated charge dynamics, favoring charge separation and utilization. Meanwhile, the catechol and amino groups of PDA facilitate Pt anchoring, and hydrogen bonding and π-π stacking interactions between PDA and PDI-COOH reinforce the supramolecular framework. These coupled effects enable efficient and durable hydrogen evolution, highlighting PDA-mediated interfacial engineering as an effective strategy for advancing PDI-based supramolecular photocatalysts.