Giant Internal Electric Field in Ni-Modified Perylenetetracarboxylic Acid Supramolecule via Metal-Coordination...

Developing efficient supramolecular photocatalysts is essential for green H₂ production using solar energy, yet their performance is often limited by inefficient photogenerated charge separation. Herein, this study innovatively employs the coordination-driven self-assembly of Ni²⁺ ions and perylenetetracarboxylic acid (PTA) to construct a Ni-PTA supramolecular photocatalyst, achieving significantly enhanced photocatalytic H₂ evolution performance. Experimental and theoretical results confirm that Ni²⁺ ions are inserted into PTA interlayers via monodentate coordination with carboxyl groups, inducing pronounced charge polarization and substantially augmenting the molecular dipole moment of Ni-PTA. The enhanced dipole establishes a giant internal electric field (IEF) within Ni-PTA, thereby reducing exciton binding energy and increasing charge-separation efficiency by 4.2-fold. Thus, Ni-PTA exhibits excellent and stable photocatalytic H₂ evolution, with a rate of 496.7 µmol h^-1, 3.8 times higher than that of self-assembled PTA supramolecules. Meanwhile, a notable apparent quantum efficiency of 16.5% at 420 nm is achieved, surpassing most reported supramolecular photocatalysts. Furthermore, the Ni-PTA film sample also shows stable operation with a H₂ evolution rate of 17.7 mmol m^-2 h^-1, demonstrating promising practical applicability. In summary, this work highlights that metal-coordination engineering enhances the IEF of supramolecular photocatalysts for promoting charge separation, providing a new design strategy for efficient photocatalysts.