This work reports on synthesis of zinc oxide/reduced graphene oxide (ZnO/rGO) nanocomposites in the presence of diethylenetriamine (DETA) via a facile microwave method. The X-ray diffraction (XRD) patterns of the nanocomposites correspond to the ZnO hexagonal phase wurtzite structure. The high-resolution transmission electron microscopy (HRTEM) images revealed that the ZnO nanorods, with an average length？:？diameter ratio of 10, were successfully deposited on the rGO sheets. Under the irradiation of sunlight, the nanocomposites showed enhanced adsorption-photocatalysis by more than twofold and photocurrent response by sixfold compared to the ZnO. The excellent photoactivity performance of the nanocomposites is contributed by smaller ZnO nanorod and the presence of rGO that acts as a photosensitizer by transferring electrons to the conduction band of ZnO within the nanocomposite during sunlight illumination. 1. Introduction Direct discharge of pigments and dyes by textile industries into waters endangers the aquatic lives. The colours block the sunlight from passing through the water, causing disturbance to the natural growth cycles of the living organisms in the waters. The heavy metals and organic and inorganic complexes used in the making of pigments and dyes are highly toxic and will accumulate in the fat deposits of large fishes which will be consumed by organisms in the higher order on land. Conventional biological treatments are only effective to adsorb the dye, causing secondary pollution [1, 2]. Photocatalysis is a method used to eliminate organic compounds in wastewater by mineralizing them into the simplest compounds like water and carbon monoxide. Semiconductor photocatalysts have been studied extensively because of favorable combination of electronic structure, light absorption properties, and charge transport characteristics. ZnO has been known as a suitable alternative to TiO2 because of its strong oxidizing power, nontoxicity, and being relatively inexpensive. Its wide band gap (3.37？eV) and higher electron mobility hamper its use as a photocatalyst [3–6]. In an effort to improve the photocatalytic efficiency of ZnO, it has been doped, loaded, and combined with metals, nonmetals, and semiconductors [7–10]. Recently, researchers are astounded with graphene because of its unique electronic properties and large theoretical specific surface area. These properties make graphene a good candidate for combination with the ZnO because graphene’s pristine mechanical performance stabilizes catalysis and offers a two-dimensional plane to deposit
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