Photooxidation of benzyl alcohols and photodegradation of cationic dyes by Fe3O4@sulfur/reduced graphene oxide as catalyst

Abstract

Wide sheets of graphene oxide (GO) were prepared by the Hummers' method. Raman spectroscopy and AFM images were used to characterize the prepared GO. A one-step green chemistry method was used to prepare sulfur/reduced graphene oxide (S/RGO). Magnetic nanoparticles were added to S/RGO to prepare Fe₃O₄@S/RGO composite. The prepared composites were investigated by X-ray diffraction (XRD), Fourier-transform infrared (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray (EDX) mapping, transmission electron microscopy (TEM), and scanning electron microscopy (SEM) imaging. The magnetism of the composite was measured using a vibrating sample magnetometer (VSM). Diffuse reflectance spectroscopy (DRS) was used to find band gaps of samples. Experimental tests distinguished kinetic photocatalyst degradation of methylene blue (MB) and crystal violet (CV) in presence of the prepared catalysts under visible light irradiation. The results demonstrated that Fe₃O₄@S/RGO has excellent degradation activity in comparison to GO, pure sulfur, and S/RGO. Furthermore, photodegradation of MB is more efficient than CV. Fe₃O₄@S/RGO also was used for photooxidation of substituted benzyl alcohols to their corresponding benzaldehydes. Selectivity and conversion of the oxidation reaction was demonstrated by TLC and GC.