Visible light-driven photocatalytic degradation of rhodamine 6G using reduced graphene oxide/zinc oxide/iron oxide from zinc dross

In this study, zinc dross was exploited as a source of zinc oxide (ZnO) and iron (III) oxide (Fe2O3) to fabricate reduced graphene oxide (rGO), ZnO, and Fe2O3 nanocomposites (namely rGO/ZD sample) for visible light-driven photocatalytic degradation of rhodamine 6G. A combination of X-ray diffraction, energy dispersive X-ray spectroscopy, and Raman spectroscopy confirmed the presence of rGO, ZnO, and Fe2O3 in the rGO/ZD sample. Field emission scanning electron observations confirmed the addition of rGO could prevent the agglomeration of ZD particles. Diffuse reflectance spectroscopy examination revealed that the bandgap of the ZnO/Fe2O3 (namely ZD) sample is 2.66 eV, suggesting the presence of Fe2O3 could reduce the ZnO's bandgap energy. Compared to other single component samples, the rGO/ZD sample achieved the highest degradation rate of 37.0 +/- 2.9% and can remove 3.86 x 10-5 mmol of dye/mg of catalyst under visible light irradiation. Energy transfer rate of rGO/ZD sample (4.62 x 107 s-1) is almost three times higher than ZD sample (1.56 x 107 s-1) and energy transfer efficiency of rGO/ZD sample (23.08%) is 2.5 times higher than ZD sample (9.23%), implying the presence of rGO plays an important role to boost photocatalytic performance of ZD sample. By using zinc dross as a source of zinc and iron to form the rGO/ZnO/Fe2O3 photocatalyst in the rGO/ZD sample, this research underscores the potential of recycling waste as a promising photocatalyst for the photocatalytic degradation of dyes in water, which is beneficial for our environment through sustainable industrial practices.