Hydrothermal synthesis of g-C3N4/CdWO4 nanocomposite and enhanced photocatalytic activity for tetracycline degradation under visible light

Abstract

Novel visible light responsive g-C₃N₄/CdWO₄ photocatalysts were formed by an in situ growth mechanism and employed in the degradation of a tetracycline (TC) antibiotic. The as-prepared composites were studied by several characterization techniques. Results revealed that the interface interaction between CdWO₄ and g-C₃N₄ was recognized via CdWO₄ nanorod loading on the surface of the layered g-C₃N₄, improving the separation and transfer of the photoexcited hole and electron pairs and restraining the recombination rate of photoinduced charge carriers. As a result, the photocatalytic activity of the g-C₃N₄/CdWO₄ was enhanced in comparison with pure g-C₃N₄ and CdWO₄ for TC degradation under visible light irradiation. Among the as-synthesized samples, the 80 wt% g-C₃N₄/CdWO₄ photocatalyst showed optimal photocatalytic efficiency, which was about 4.0 and 20.0 times higher than that of bare g-C₃N₄ and CdWO₄ under visible light irradiation, respectively. Significantly, the g-C₃N₄/CdWO₄ composites exhibited better stability even after four successive cycles for TC degradation under visible light irradiation. Based on the active radical trapping and electron spin resonance (ESR) experiments, the possible mechanism of enhancing photocatalytic activity under visible light irradiation (λ > 420 nm) was proposed, to lead to further improvement in environmental remediation.