One step solvothermal synthesis of urchin-like ZnO nanorods/graphene hollow spheres and their NO 2 gas sensing properties

Abstract Hierarchical urchin-like hollow spheres of ZnO nanorods with reduced graphene oxide (Urc-ZGO) have been synthesized via an efficient one step solvothermal method. The ZnO hollow spheres with a size of 0.5–2 µm are anchored homogeneously on the surface of reduced graphene oxide (RGO) layers. When used as a gas sensor for detection of NO 2 , the Urc-ZGO composite shows much higher sensitivity towards NO 2 at room temperature (RT) than the corresponding RGO. It is found that Urc-ZGO hollow spheres prepared with 30 mg weight addition ratio of graphene (Urc-ZGO-30) exhibit the highest response at RT. The obvious enhancement of the gas sensing properties is attributed to the hierarchical hollow spheres in the structure of Urc-ZGO.