Supramolecularly engineered S-scheme photocatalysts: Dual hydrogen bonds lock H12SubPcB-OCONaPhOH/Ag3PO4 interface for directed electron transfer

A supramolecular breakthrough in photocatalytic heterojunction design is achieved through hydrogen-bond-driven assembly of an organic–inorganic S-scheme system. Axial hydroxyl-functionalized subphthalocyanine (SubPc-5) spontaneously self-assembles into a hydrogen-bonded organic framework (HOF) via intermolecular O–H⋯O/N interactions while simultaneously anchoring onto Ag 3 PO 4 surfaces through interfacial carboxyl-oxygen hydrogen bonds, forming a structurally coherent heterojunction. Advanced characterizations combining density functional theory (DFT), synchrotron irradiation XPS (SI-XPS), and Kelvin probe force microscopy (KPFM) demonstrate this dual-level hydrogen bonding strategy creates a built-in electric field that drives directional charge separation while suppressing recombination. The resulting SubPc-5/Ag 3 PO 4 system exhibits extended visible-light absorption, prolonged carrier lifetimes and exceptional stability. These synergistic effects enable ultrahigh photocatalytic degradation efficiencies of 99.0 % for chlortetracycline and 98.5 % for ciprofloxacin within 30 min, with kinetics 4-fold faster than pristine Ag 3 PO 4 . Molecular dynamics simulations further reveal strong π-π interactions between SubPc-5 and pollutant molecules, facilitating adsorption and degradation. This work not only achieves record-performance antibiotic degradation but also establishes hydrogen-bonding as a universal strategy for constructing organic-inorganic heterostructures with precisely controlled charge-flow pathways, opening new avenues for supramolecular photocatalyst design.