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

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. The S-scheme heterojunction supramolecular array, comprising H12SubPcB-Br (SubPc-Br)/UiO-66, is successfully constructed through the synergistic interaction of van der Waals force and the B-O-Zr bonds at the interface. Importantly, the apparent rate constant for the degradation of MC by SubPc-Br/UiO-66 is found to be 2.20 times higher compared to the pristine UiO-66.These findings provide new ideas for the field of photocatalysis.image