Enhanced photocatalytic degradation of methylene blue by reduced graphene-oxide/titanium dioxide/zinc oxide ternary nanocomposites

In this report, an attempt has been made to prepare reduced graphene-oxide/Titanium dioxide/Zinc oxide (rGO/TiO₂/ZnO) ternary photocatalyst system via a facile two step solvothermal method and their results were compared with rGO/TiO₂ and TiO₂. The structural, morphological and optical properties were explored using X-Ray diffraction (XRD), Scanning electron microscope (SEM), Energy Dispersive Spectra (EDS), Raman and Photoluminescence (PL). SEM images noticeably present the 2D sheet morphology of GO, irregular spherical morphology of TiO₂ and nanorods morphology of ZnO. XRD pattern depicted the formation of TiO₂ anatase and wurtzite hexagonal structure of ZnO, which is highly desirable for photocatalysis application. Further, the results of Raman spectra are in good agreement with the XRD data. The PL spectra evidently revealed the quenching effect of electron-hole recombination process. The photocatalytic degradation of the system was investigated using a model dye methylene blue (MB). The efficiency of the ternary system was evaluated and compared using rGO/TiO₂ and TiO₂. The degradation efficiency of rGO/TiO₂/ZnO, rGO/TiO₂ and TiO₂ was found to be 92%, 68% and 47% within 120 min respectively. Our results will pave the way for the development of futuristic rGO based ternary nanocomposites for photocatalytic applications.