Abstract: For the efficient harnessing of solar energy and mitigation of environmental pollution, the development and application of semiconductor photocatalysis technology is paramount. Herein, a novel SubPc-Br/CdS supramolecular array with an S-scheme heterojunction was synthesized through the intermolecular π-stacked self-assembly of subphthalocyanine (SubPc-Br) and nanometer cadmium sulfide (CdS). This self-assembly system features a highly structured architecture and excellent stability. Experiments and ground-state differential charge calculations demonstrate that SubPc-Br and CdS form a built-in electric field during the self-assembly process, a critical factor in promoting the dissociation of electrons and holes. Additionally, this study utilized time-dependent density functional theory (TDDFT) to simulate the dynamic adsorption behavior of excited oxygen molecules on the SubPc-Br/CdS interface for the first time. The analysis of molecular charge differential density under different excited states proved that the addition of SubPc-Br molecules not only improves the photocorrosion resistance of CdS in an O₂ adsorption environment but also enhances the production of advanced reactive oxygen species under the synergistic action of h⁺ and .O₂^-. When subjected to visible light, the degradation efficiency of minocycline (MC) achieved 96.8 % within 60 min and maintained 80.3 % after 5 cycles. In summary, this study highlights the feasibility of creating advanced S-scheme heterojunction photocatalysts through the strategic incorporation of organic supramolecules with semiconductor catalysts.

Key words: Photocatalytic oxidation, TDDFT, SubPc-Br/CdS, S-scheme heterojunction