A facile approach of fabricating graphene-encapsulated ZnO microspheres and their synergic effect on photocatalytic performance

A facile approach of fabricating homogeneous graphene (GE)-encapsulated ZnO microspheres (ZnO microspheres@GE) by bubbling, sonicating, freeze drying, and reduction is developed. The transmission electron microscopy results reveal an intimate interface between GE and ZnO. The as-synthesized ZnO microspheres@GE composites exhibit much higher adsorption capability and excellent photocatalytic activity for methylene blue compared with bare ZnO microspheres, which should be attributed to improved carrier transport efficiency and large surface area arising from the graphene encapsulating. Besides of that, due to the characters of non-functionalized and easy reproducibility, it should be extended to synthesis of GE-encapsulated other semiconductors as well.