Visible-lightdriven C–TiO2 nanocomposites were prepared via a simple calcination and acid etching process. The C–TiO2 nanocomposites were characterized by X-ray photoelectron spectroscopy, Raman spectroscopy, X-ray diffraction, transmission electron microscopy, and high-resolution TEM. The results showed that TiO2 nanoparticles were combined with a porous carbon layer through surface C–O groups, which facilitates the strong interface interaction. The interface combination of nano-TiO2 and carbon material increases the specific surface area of nano-TiO2, widens the range of light response, and improves the efficiency of light-induced electron migration. The visible-light photocatalytic activity of the prepared photocatalyst was evaluated by the decomposition of tetracycline aqueous solution. Compared with that of pure TiO2, the photocatalytic activity of C–TiO2 nanocomposites was significantly improved. Furthermore, a possible photocatalytic mechanism was also tentatively proposed. This work can promote the development of active photocatalysts under solar light for the photodegradation of environmental pollutants.

The resource utilization of waste plastic can not only control environmental pollution but can also ease up the problems of lack of energy resources. In this study, molybdenum carbide (Mo 2 C) nanoparticles have been synthesized by utilizing waste polyvinyl chloride as a carbon source in a stainless-steel autoclave at 600 °C. X-ray diffraction pattern indicates that the product is orthorhombic phase Mo 2 C. Electron microscopy photographs show that the obtained Mo 2 C product consisted of crystalline nanoparticles with an average size of 50 nm. The possible formation mechanisms of Mo 2 C have been also briefly discussed on the basis of the structures of the products synthesized with different reaction times. The effects of reaction temperature on the crystallinity and microstructure of the obtained products have been investigated. The results show that higher reaction temperature promotes the formation of Mo 2 C with high crystallinity.