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In this study, ternary catalyst g-C3N4/Ag2CO3/graphene oxide was synthesized through a simple chemical precipitation method at room temperature. The CN/AC/GO composite was employed to degrade antibiotics under visible light irradiation. And the results indicated that the composite possessed excellent photocatalytic performance, which could remove 81.6% tetracycline (TC) after 60 min of irradiation. The PL, EIS, PC and UV–vis DRS tests demonstrated that enhanced photocatalytic efficiency could be attributed to rapid charge transfer, low recombination rate of photo-induced electron-hole pairs, as well as superior light absorption capability. Moreover, three-dimensional excitation-emission matrix fluorescence spectra (3D EEMs) were employed to further grasp the behaviors of TC molecules in the process of degradation reaction. In addition, the liquid chromatography-mass spectrometry (LC-MS) was carried out to explore the intermediates during the photocatalytic reaction. Meanwhile, the influences of initial TC concentration, light source, supporting electrolytes and water sources were explored from the perspective of practical application. Furthermore, the appearance of a small amount of Ag nanoparticles (NPs) not only accelerated the charge transfer, but also improved the stability of catalyst. The composite also possessed high stability and reusability, which were essential in practical application.

A novel stereo porous and highly stable photocatalyst CdS/TiO2-400 (composite CdS/TiO2 calcined at 400 °C) was synthesized by hydrolysis-hydrothermal-calcined method without the assistance of template. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), ultraviolet–visible diffuse reflectance spectra (UV–vis DRS), transient photocurrents, photoluminescence emission spectra (PL) and Brunauer-Emmett-Teller (BET) to study their crystallinity, morphologies, structure, optical properties and specific surface area. The experimental results validated that as-prepared CdS/TiO2-400 could effectively improve the separation efficiency of photogenerated electron-hole pairs and displayed superior photocatalytic activity in the degradation process of methyl orange (MO), oxytetracycline (OTC) and tetracycline (TC). The promoted photocatalytic activity was attributed to the calcination procedure and high specific surface area. A possible photocatalytic mechanism of CdS/TiO2-400 was proposed on the basis of trapping experiments.

A kind of Ag/AgCl hollow spheres were synthesized with the assist of Cu 2 O nanospheres via simple chemical methods The Cu 2 O nanospheres were used for template as well as raw material. The FeCl 3 aqueous solution, as the Cl − and weak acid environment provider, was played an important role in the removal of Cu 2 O template and the formation of Ag/AgCl hollow spheres. The X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), Brunauer-Emmett-Teller (BET), photoluminescence emission spectra (PL), ultraviolet-visible diffuse reflectance spectra (UV-vis DRS) and transient photocurrents were employed to investigated the crystal structures, morphologies, specific surface area and optical property of the samples. The experiment results confirmed that the harvest of visible light and separation efficiency of electron-hole pairs were enhanced significantly owing to the large specific surface area and porous structure of hollow spheres. In comparison with common Ag/AgCl, the as-prepared Ag/AgCl hollow spheres exhibited excellent photocatalytic activity on the degradation for rhodamineB (RhB), methyl orange (MO), methylene blue (MB) oxytetracycline (OTC) and tetracycline (TC) under visible light irradiation (λ > 420 nm). The possible photocatalytic mechanism was also proposed on the basis of trapping experiment.