A flower-like hierarchical graphene oxide/ZnO (GO/ZnO) macrospheres were fabricated via a low-temperature hydrothemal method, and their photocatalytic performance was tested under natural sunlight and darkness. The resultant GO/ZnO sample displays unique hierarchical macrosphere with diameters in the range of 2–3 μm. The photocatalytic activity of the GO/ZnO microspheres depended on GO, and GO/ZnO macrosphere containing 0.37% GO exhibited very high photocatalytic activity under natural sunlight irradiation and without stirring. Furthermore, G...