Controllable synthesis of CeO2/g-C3N4 composites and their applications in the environment

Abstract

This research has developed a photocatalytic reactor that includes circulating water, light, and a temperature control system. CeO₂/g-C₃N₄ composites with high photocatalytic activity and stability were synthesized by a simple and facile hydrothermal method. The obtained photocatalysts were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). It was found that in the CeO₂/g-C₃N₄ composites, the CeO₂ nanoparticles were homogeneously cubic in shape (from 3 to 10 nm) and were evenly dispersed on the surface of the g-C₃N₄. At constant temperature (30 °C), 5% CeO₂/g-C₃N₄ photocatalyst showed the best photocatalytic activity for degrading organic dye methylene blue (MB) under visible light irradiation. The photocatalytic reaction for degrading MB followed first-order kinetics and 5% CeO₂/g-C₃N₄ exhibited a higher apparent rate of 1.2686 min⁻¹, 7.8 times higher than that of the pure g-C₃N₄ (0.1621 min⁻¹). In addition, it was found that 5% CeO₂/g-C₃N₄ had a new property that it could be used as a sensor for the determination of trace amounts of Cu²⁺. Such unique design and one-step synthesis, with an exposed high-activity surface, are important for both technical applications and theoretical investigations.