Hierarchical 2D/2D Bi2MoO6/Nb2CTx Schottky heterojunction for enhanced photocatalytic removal of antibiotics

초록

Constructing heterojunction photocatalysts is a promising approach for degrading harmful antibiotics. Here, we present a novel composite photocatalyst, the Bi2MoO6/Nb2CTx (BMNC) Schottky heterojunction, which synergistically integrates the layered structure of Bi2MoO6 with the unique morphology and superior conductivity of Nb2CTx. The composite was synthesized via the in situ growth of Bi2MoO6 nanosheets on Nb2CTx nanosheets through a one-step hydrothermal route. In the BMNC composite, Bi2MoO6 was strongly anchored to Nb2CTx, forming a hierarchical sheet-on-sheet (2D/2D) structure. This architecture offered a large surface area, more exposed active sites for photocatalytic reactions, and extended light absorption in the visible region. Moreover, the Schottky barrier formed at the interface provided a one-way channel for electron transfer, thereby effectually suppressing electron-hole recombination and prolonging carrier lifetime. As a result, the BMNC-50 composite (containing 50 mg of Nb2CTx) achieved removal efficiencies of 96.98 % for ciprofloxacin and 94.77 % for tetracycline within 120 min. The photocatalyst also exhibited good structural and chemical stability after several cycles. The photocatalytic mechanism was elucidated through band structure analysis. The radical trapping tests and EPR results confirmed that center dot O2-, center dot OH, and h+ were the radical species involved in the degradation process. The developed Bi2MoO6/Nb2CTx Schottky heterojunction can provide a valuable contribution toward advancing the effective photocatalytic removal of antibiotic pollutants.

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