Improved gas sensing properties of silver-functionalized ZnSnO3 hollow nanocubes

Abstract

Hollow ZnSnO₃ nanocubes were successfully synthesized by a simple solvothermal strategy and then silver nanoparticles were decorated on the surface of ZnSnO₃ by an effective deposition method. The morphology, microstructure, crystalline nature and the chemical compositions of the products were characterized by a variety of techniques including X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The prepared Ag-functionalized ZnSnO₃ was found to be a novel porous hollow structure by characterization. This structure has a larger specific surface area and high gas permeability, thus allowing the material to make sufficient in contact with the analyte molecules. In order to further study the gas sensing performance of the samples, Ag-functionalized ZnSnO₃ gas sensors were fabricated. The results show that Ag-functionalized ZnSnO₃ nanocubes could enhance the gas sensing properties of ZnSnO₃ to acetone. In particular, the Ag-functionalized ZnSnO₃ with an atomic ratio of 0.6% realized a high gas response, ultrafast response/recovery speed, a low detection limit (1 ppm) and strong selectivity to acetone. The response of the Ag-functionalized ZnSnO₃ sensor was 31.62–100 ppm, which was 3.18-times higher than that of the pristine ZnSnO₃ hollow nanocubes. In addition, the formation mechanism of the hollow structure and the mechanism of Ag modification to improve the sensing performance of ZnSnO₃ sensor were discussed.