Inorganic semiconductors prepared from MOFs as sacrificial precursors are promising photocatalytic materials. In this work, the direct Z -scheme MoS 2 /NH 2 -MIL-68(In)-derived In 2 S 3 (MoS 2 /In 2 S 3 ) heterojunction composites have been synthesized by sulfidation treatment of MoS 2 /NH 2 -MIL-68(In) (MoS 2 /NM68) composites. Morphological and crystal structural results confirmed that MoS 2 was uniformly dispersed in In 2 S 3 . According to the reduction for Cr(VI) experimental results, the photocatalytic performance of MoS 2 /In 2 S 3 heterojunction composite under visible light irradiation is significantly better than that of pristine MoS 2 and In 2 S 3 , respectively. In addition, the photocatalytic activities of the MoS 2 /In 2 S 3 (II) at different pH and high concentrations of Cr(VI) were also investigated. This paper presents a novel approach to the construction of heterojunction photocatalytic materials using MOFs as sacrificial precursors.
Tubular carbon-covered cobalt-doped bi-crystalline phase In 2 O 3 (denoted as CoInO-x) was synthesized by one-step calcination of the metal-organic framework cobalt-doped MIL-68(In)-NH 2 precursor. The photocatalytic activity of CoInO-x was investigated using tetracycline hydrochloride (TCH) degradation. The removal of TCH by CoInO-500 obtained by calcination at 500 °C under visible light irradiation was 90.1% after 70 min, which was significantly higher than that of In 2 O 3 . The reaction rate constant of CoInO-500 was 11.02 times higher than that of In 2 O 3 and could maintain a better photocatalytic performance after four cycles. The effects of photocatalyst dosing, pH, and inorganic anions on photocatalytic degradation were studied. The mechanism of photocatalytic degradation was analyzed in detail by reactive radical trapping experiments, Mott-Schottky measurements, and electron paramagnetic resonance (EPR) signal characterization. Enhanced photocatalytic performance is mostly attributed to the cobalt doping creating impurity energy levels and narrowing the forbidden bandwidth of In 2 O 3 , enhancing the visible light utilization and the photogenerated charge separation efficiency. Carbon covering can serve as a bridge for charge transport, accelerating the rapid transport of photogenerated charges.
Exploring effective approach to promote more comprehensive charge transfer and efficient spatial charge separation is considered to be a prospective strategy to reinforce photocatalytic degradation activity. Herein, the oxygen vacancy modified Bi 2 WO 6 /NH 2 -MIL-68(In) Z-scheme heterojunction photocatalyst was successfully fabricated via a facile solvothermal method. The chemical structure, morphology, and optical properties of the photocatalyst were characterized in detail. The optimized Bi 2 WO 6 /NH 2 -MIL-68(In) Z-scheme heterojunction displayed the maximum photocatalytic efficiency (84.3 %) for the degradation of levofloxacin (LEV), which was significantly higher than that of pure Bi 2 WO 6 (45.1 %), oxygen vacancy modified Bi 2 WO 6 (69.4 %), and NH 2 -MIL-68(In) (49.3 %). Importantly, the high-resolution mass spectrometry (HRMS), three-dimensional excitation-emission matrix (3D EEMs) fluorescence spectra, the photo-electrochemical and photo-luminescence measurement, radical trapping test, and electron spin resonance (ESR) technique were carried out to illuminate the probable degradation pathway and mechanism of the LEV. The improved photocatalytic efficiency can be ascribed to the synergetic effect between oxygen vacancy and the Z-scheme heterojunction, which can serve as trapping centers to enhance the generation of photoexcited electrons and accelerate the charge transfer. Meanwhile, the effects of pH, photocatalyst dose, LEV concentration and different kinds of harmful organic pollutants were systematically explored from the practical application. This study offers a novel perspective for the integration of defect engineering and Z-scheme heterojunction in efficient organic pollutants degradation.
危险品化学品经营许可证（带存储）