Synthesis of type II heterojunction 2D/3D Bi2S3/MIL-88(A) with enhanced photocatalytic activity under visible-light irradiation

The aim of this article is to provide an effective catalyst for using photocatalytic technology to solve the antibiotic pollution. For this purpose, Bi2S3 was loaded on the surface of MIL-88 (A) to prepare rod-shaped composite photocatalyst via a combination of low-temperature hydrothermal and low-temperature water bath methods. The prepared composite photocatalysts were characterized by using SEM, EDS, XRD, FT-IR, UV–vis and XPS. Tetracycline hydrochloride (TC) degradation under visible light was used to gauge the photocatalytic activity of the composite as it was created. The results show that the degradation efficiency of the optimum sample Bi2S3/MIL-88 (A)-0.2 to TC within 120 min in a 10 mg/L TC solution is as high as 93%, which is 5.74 and 4.39 times as high as that of pure MIL-88 (A) and Bi2S3, respectively. The increased photocatalytic activity is ascribed to the type II heterojunctions that develop between Bi2S3 and MIL-88 (A), which contribute to increase the composite's specific surface area and separation efficiency of photogenerated carriers. Additionally, the possible photocatalytic mechanism of the composite photocatalyst is explored in detail by active species capture experiments, transient photovoltage electrochemical impedance spectroscopy and photoluminescence measurements. This research provides a new way to prepare MIL-88 (A)-based type II heterojunction photocatalysts.