Visible-light-driven photodegradation of sulfamethoxazole and methylene blue by Cu₂O/rGO photocatalysts

The cuprous oxide-reduced graphene oxide (Cu₂O/rGO-x) composites were prepared via a simple wet-chemical method by using CuSO₄·5H₂O and graphene oxide as precursors and ascorbic acid as a reducing agent, respectively. These Cu₂O/rGO-x were employed as photocatalysts for degrading emerging contaminants and organic dye pollutants (i.e., sulfamethoxazole (SMX) and methylene blue (MB)) under visible light. A variety of different spectroscopic and analytical techniques, such as X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, Raman scattering spectroscopy and UV-Visible spectroscopy were used to characterize the physical properties of photocatalysts. In the photodegrading experiments, it can be found that the Cu₂O/rGO-80 photocatalyst has the superior visible-light response of ca. 50% removal efficiency of SMX within 120 min and 100% removal efficiency of MB within 40 min. These observations may be attributed the well-dispersed and visible-light-responsive Cu₂O nanoparticles are supported on the surface of rGO sheets that can enhance absorption of visible light during photocatalysis.