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A novel MOF-based S-scheme heterostructure of MIL101-(Fe)/Bi 2 WO 6 was designed and synthesized for efficient photocatalytic elimination of Cr(VI) and antbiotic tetracycline hydrochloride by virtue of the abundant reactive sites and OV-mediated S-scheme photo-carrier separation mechanism. [Display omitted] • A dual dual-functional photosystem of defective MIL-101(Fe)/Bi 2 WO 6 S-scheme heterojunction was designed. • MIL-101(Fe)/Bi 2 WO 6 showed excellent activity for removal of Cr(VI) and tetracycline under visible light. • The high specific surface area and OV-mediated S-scheme structure contribute to the excellent photocatalytic performance. • The degradation process of tetracycline and eco-toxicity of the intermediates were investigated. Solar-driven elimination of refractory contaminants is an ideal route to tackle the environmental issues. Nevertheless, the photocatalytic performance of photocatalysts is heavily restrained due to the insufficient accessible reactive sites and fast electrons/holes reunion. Herein, a novel metal–organic framework-based S-scheme heterostructure of MIL-101(Fe)/Bi 2 WO 6 was synthesized by a simple solvothermal approach. The optimized MIL-101(Fe)/Bi 2 WO 6 (MIL/BWO-2) affords the highest photo-activities under visible light, which are 13.7, 6.7 folds greater for Cr(VI) reduction, and 0.8, 10.5 folds higher for tetracycline hydrochloride oxidation compared with individual Bi 2 WO 6 and MIL-101(Fe), respectively. The preeminent catalytic capability lies in two aspects: 1) the introduction of MIL-101(Fe) substantially enlarges the surface area of the composites, offering ample reaction sites and fostering pollutant adsorption and mass transportation; 2) the novel S-scheme photo-carrier transport mechanism assisted by oxygen vacancies favors spatial segregation and transport of photoinduced electrons/holes with superior redox capacity. Reactive species identification experiments verify that O 2 – and e– dominantly contribute to Cr(VI) reduction, while O 2 –, h+ and OH account for tetracycline hydrochloride destruction. Furthermore, the tetracycline photo-decomposition pathway, eco-toxicity evaluation, and photocatalytic mechanism were investigated comprehensively. This research paves the way for building high-performance MOFs-based S-scheme heterojunctions toward photocatalytic water purification. [ABSTRACT FROM AUTHOR]

[Display omitted] • 0D/3D Bi 2 Sn 2 O 7 /Bi 2 MoO 6 S-scheme heterojunction was constructed. • The heterojunction exhibited excellent photocatalytic performance for antibiotics. • A plausible degradation pathway for TC was proposed. • S-scheme heterojunction largely boosted charge separation and ROS production. The fabrication of step-scheme (S-scheme) heterojunction with superior redox capability has been emerging as a prospective strategy for environmental remediation. Herein, novel Bi 2 Sn 2 O 7 /Bi 2 MoO 6 S-scheme heterojunctions have been fabricated via in-situ anchoring Bi 2 Sn 2 O 7 nanoparticles on Bi 2 MoO 6 microspheres. The optimized Bi 2 Sn 2 O 7 /Bi 2 MoO 6 (BSO/BMO-6%) attains the highest reaction rate constant (k) in the degradation of tetracycline hydrochloride (TC, k = 0.0397 min−1), which is 3.62 folds higher than that of pristine Bi 2 MoO 6. Such an improvement is originated from more exposed active sites, higher photo-excited charge separation efficiency, superior redox ability, and efficient production of reactive h+, •OH and •O2–. Besides, Bi 2 Sn 2 O 7 /Bi 2 MoO 6 could efficiently degrade the TC antibiotic in actual water matrix. Significantly, the toxicity evaluation verifies the nontoxicity of Bi 2 Sn 2 O 7 /Bi 2 MoO 6. Moreover, the degradation pathways of TC are determined and the toxicity of degradation intermediates is appraised by using HPLC-MS spectra and QSAR prediction. A possible photocatalytic mechanism over S-scheme Bi 2 Sn 2 O 7 /Bi 2 MoO 6 has been elucidated based on experimental studies combined with density functional theory (DFT) calculations. This work offers new insights for the design of high-performance S-scheme heterojunctions for environmental remediation. [ABSTRACT FROM AUTHOR]

A new 3D Ag/Ag 2 S/Bi 2 MoO 6 plasmonic p-n heterojunction photocatalyst has been designed and applied for efficiently visible-light photocatalytic degradation of pharmaceutical antibiotics. [Display omitted] • Ag/Ag 2 S/Bi 2 MoO 6 (AAS/BMO) plasmonic p-n heterojunction was constructed. • AAS/BMO displayed superior catalytic activity and great stability for antibiotics removal. • Effects of various factors on levofloxacin removal were studied systematically. • A plausible degradation pathway for levofloxacin was proposed. • Plasmonic p-n heterojunction greatly promotes charge separation and ROS production. A novel Ag/Ag 2 S/Bi 2 MoO 6 plasmonic p-n heterojunction has been constructed via the in-situ growth of p-type Ag 2 S nanoparticles on n-type Bi 2 MoO 6 microspheres, followed by the photo-reduction treatment. Simultaneously, the Ag0 loading percentage in the heterojunction could be finely controlled by tuning the photo-reduction time. The optimized Ag/Ag 2 S/Bi 2 MoO 6 (AAS/BMO-4) manifests the highest photocatalytic performance towards degrading levofloxacin (LEV) and tetracycline hydrochloride (TC), which degradation efficiencies are 87.3% and 92.8%, respectively. Such improvement mechanism could be due to the improved light absorption in the visible-light region induced by localized surface plasmon resonance (LSPR) and the efficient interfacial separation and transport of charge carriers in Ag/Ag 2 S/Bi 2 MoO 6. The impacts of some key parameters (e.g., various inorganic anions, representative organic substances and various water resources) are systematically investigated. Ag/Ag 2 S/Bi 2 MoO 6 also exhibits excellent mineralization capability and recycling performance in degrading LEV. Moreover, photo-generated h+, OH, and O 2 – are identified as the dominant reactive species accounting for the degradation of antibiotics. The photodegradation pathway of LEV has also been elucidated based on the intermediate identification. Therefore, this study not only reports an innovative plasmonic p-n heterojunction but also the new design of photocatalysts capable of efficiently degrading pharmaceutical antibiotics under visible-light irradiation. [ABSTRACT FROM AUTHOR]