Low-temperature chemical solution route for ZnO based sulfide coaxial nanocables: general synthesis and gas sensor application

A novel chemical solution approach has been developed to synthesize ZnO based sulfide coaxial nanocables such as ZnO/ZnS and ZnO/CdS by chemical reaction in tetrahydrofuran (THF; C4H8O), in which sulfur, NaBH4 and ZnCl2 or CdCl2 were used as reactants and ZnO nanorods were used as the template at room temperature. The morphology and structure of ZnO/ZnS and ZnO/ CdS coaxial nanocables have been characterized by transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), x-ray powder diffraction (XRD), x-ray photoelectron spectroscopy (XPS) and Brunauer-Emmett-Teller (BET) analysis. Furthermore, the as-prepared ZnO/ CdS coaxial nanocables have been applied as NH3 gas sensors at room temperature with superior sensitivity, good reproducibility and a short response/recovery time. Finally, a first explanation for the improved performance of the ZnO/CdS coaxial nanocable based gas sensors has been presented.