Photocatalytic Degradation of Tetracycline Antibiotics over CdS/Nitrogen-Doped–Carbon Composites Derived from in Situ Carbonization of Metal–Organic Frameworks

In view of the increasing concerns for environmental problems caused by the widespread use of antibiotics, there is an urgent demand to develop effective technologies for antibiotics removal from pharmaceutical wastewater. For this purpose, photocatalysis has been developed as an important advanced oxidation technology possessing remarkable prospective, and thus, the semiconductor photocatalysts are currently attracting unprecedented research attention. Herein, we report the fabrication of composite materials based on nitrogen-doped carbons and cadmium sulfide semiconductors (CdS/NC–T) derived solely from cadmium metal–organic frameworks (Cd–MOF) through a facile in situ carbonization method, as well as their application as viable photocatalysts toward tetracycline degradation under visible irradiation. It was revealed that cadmium and sulfur species in Cd–MOF precursors assembled to form CdS nanoparticles (NPs), which were deposited simultaneously on nitrogen-doped carbon scaffolds to afford CdS/NC–T composites during carbonization processes. PXRD and TEM studies on as-prepared CdS/NC–T materials indicated the formation of crystalline hexagonal (Wurtzite) CdS NPs on carbonaceous supports. These CdS/NC–T composites were further studied for photocatalytic tetracycline degradation in aqueous solutions under visible irradiation, among which CdS/NC–500 exhibited the highest TC degradation efficiency of ca. 83% within 1 h. It was found that the photocatalytic performance of CdS/NC–T depended largely on carbonization temperature, which suggested great potentials of the proposed synthetic pathway in engineering of new visible-light-driven photocatalysts.