Confinement-Deconfinement Engineering Induces Ultrastrong Dipole Moments in Metastable Assemblies: Driving Leap in Photocatalytic Hydrogen Evolution Efficiency

The high exciton binding energy ( E b ) in symmetric organic photocatalysts has long hindered solar-to-hydrogen efficiency. Here, a confinement-deconfinement engineering strategy is presented that transforms molecular symmetry from an intrinsic limitation into a tunable design parameter. By confining symmetric molecules within layered double hydroxide interlayers, a highly oriented stacking configuration is enforced, compelling molecules to deviate from their thermodynamically stable modes. Subsequent deconfinement preserves this metastable structure. This confinement-deconfinement synergy induces giant dipole moments (22.50 Debye) and internal electric fields, collectively reducing E b to 44.42 meV (comparable to inorganic semiconductors). Interfacial water molecules activated by deconfinement act as structural co-architects, further dynamically stabilizing the metastable supramolecular assemblies (SA) via hydrogen-bonding networks. The optimized SA achieves a hydrogen evolution rate of 100.48 mmol · g −1 · h −1 , representing the current state-of-the-art. These results establish confinement-deconfinement engineering as a universal paradigm for enhancing photocatalytic performance, as it enables controlled symmetry-to-function conversion across diverse symmetric molecular systems.