Boosting photocatalytic water oxidation via interfacial electric field-mediated charge separation in S-scheme photocatalyst

Abstract

The major challenge in photocatalytic water splitting lies in water oxidation reactions, which still suffer from poor charge separation. This study overcame inefficient charge separation by establishing a robust interfacial electric field through the electrostatic-driven assembly of Co₃O₄ nanoparticles with a perylene imide supramolecule (PDINH). The well-aligned band structures and intimate interfacial contact in the PDINH/Co₃O₄ heterostructure create an enhanced interfacial electric field that is 4.1- and 53.2-fold stronger than those of individual PDINH and Co₃O₄, thus promoting directional charge separation and transfer. Moreover, S-scheme charge transfer strongly preserves the oxidative holes in PDINH to drive efficient water oxidation reactions. Consequently, PDINH/Co₃O₄ composite achieves a photocatalytic oxygen evolution rate of 29.26 mmol g^–1 h^–1 under visible light irradiation, 8.2-fold improvement over pristine PDINH, with an apparent quantum yield of 6.66% at 420 nm. This study provides fundamental insights into interfacial electric field control for the development of high-performance organic photocatalysts for efficient water oxidation.