Enhanced Charge Transfer via S-Scheme Heterojunction Interface Engineering of Supramolecular SubPc–Br/UiO-66 Arrays for Efficient Photocatalytic Oxidation

Abstract

Constructing heterojunction of supramolecular arrays self-assembled on metal–organic frameworks (MOFs) with elaborate charge transfer mechanisms is a promising strategy for the photocatalytic oxidation of organic pollutants. Herein, H12SubPcB–Br (SubPc–Br) and UiO-66 are used to obtain the step-scheme (S-scheme) heterojunction SubPc–Br/UiO-66 for the first time, which is then applied in the photocatalytic oxidation of minocycline. Atomic-level B–O–Zr charge-transfer channels and van der Waals force connections synergistically accelerated the charge transfer at the interface of the SubPc–Br/UiO-66 heterojunction, while the establishment of the B–O–Zr bonds also led to the directional transfer of charge from SubPc–Br to UiO-66. The synergy is the key to improving the photocatalytic activity and stability of SubPc–Br/UiO-66, which is also verified by various characterization methods and theoretical calculations. The minocycline degradation efficiency of supramolecular SubPc–Br/UiO-66 arrays reach 90.9% within 30 min under visible light irradiation. The molecular dynamics simulations indicate that B–O–Zr bonds and van der Waals force contribute significantly to the stability of the SubPc–Br/UiO-66 heterojunction. This work reveals an approach for the rational design of semiconducting MOF-based heterojunctions with improved properties.