Co₃O₄-rGO-Synthesis, Characterization, and Evaluation of Photocatalytic Activities

Water contamination with synthetic dyes is an escalating problem worldwide. Herein, Co3O4-decorated reduced graphene oxide (Co3O4-rGO) is reported as an effective heterogeneous photocatalyst for the decomposition of organic dyes. The synthesis of Co3O4-rGO was confirmed via spectroscopic techniques including XRD, XPS, TEM, and FTIR. After characterization, the prepared Co3O4-rGO composite was tested as a photocatalyst for the degradation of methylene blue and methyl orange. The photocatalytic efficiency of Co3O4-rGO was >95% after 60 min, corresponding to 200 mg/L as the initial concentration of each dye. The photodegradation of MB and MO was confirmed by BOD and COD measurements. Experimental parameters like the re-usability of Co3O4-rGO, the effect of catalyst dosage, and the effect of dye concentration on photocatalytic activity were also investigated. The photocatalytic activity of Co3O4-rGO for the degradation of MB was 2.13 and 3.43 times higher than that of Co3O4 and rGO, respectively. Similarly, the photocatalytic activity of Co3O4-rGO for the degradation of MO was 2.36 and 3.56 times higher than that of Co3O4 and rGO, respectively. Hence, Co3O4-rGO was found to be an efficient and reusable photocatalyst for the decomposition of selected dyes in the aqueous medium.