Physical properties and enhanced photocatalytic activity of ZnO-rGO nanocomposites

Both zinc oxide (ZnO) and reduced graphene oxide (rGO) are known for its attractive optical properties in their nano form. Here, ZnO-rGO nanocomposites and rGO were prepared via simple and reproducible hydrothermal as well as modified Hummer’s method. Microstructural identification of phase formation and dispersion of ZnO on rGO was confirmed by X-ray diffraction and transmission electron microscopy (TEM) measurements. The reduction of graphene oxide was confirmed by the appearance of D and G band peaks in Raman spectra. Optical bandgap of samples was estimated by UV–Visible diffused reflectance spectroscopy up to IR region. A systematic study of photocatalytic behavior towards the degradation of organic dyes such as methyl orange and rhodamine B under the influence of UV light source is demonstrated. Better than 85% of degradation was measured for both the dyes in the presence of ZnO-rGO composite during 2 h of UV illuminations. The enhanced photocatalytic activity of the composites is attributed to electron–hole charge transfer, which also promises its use in photovoltaics.