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

ABSTRACT 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.