Preparation of a leaf-like CdS micro-/nanostructure and its enhanced gas-sensing properties for detecting volatile organic compounds

A novel leaf-like CdS micro-/nanostructure was prepared via a hydrothermal method using dimethyl sulfoxide as the growth template. The as-synthesized hierarchical micro-/nanostructures were characterized by field emission scanning electronic microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectrometry (XPS). The elemental mapping and the line scans were also performed in the high-angle annular dark-field (HAADF) mode on the same TEM. The growth mechanism was demonstrated from the aspects of time-dependent growth processes and different influencing factors including temperatures and templates. In gas-sensing measurements, typical volatile organic compounds at a series of concentrations were employed as the target analytes, including ether, methanol, acetone and isopropanol. We found that the gas sensor based on the special leaf-like CdS micro-/nanostructures exhibited a fascinating performance including high response, short response/recovery times and good recognition ability towards different analytes. The detecting limits towards ether, methanol, acetone and isopropanol could be lower than 25, 50, 50, and 10 ppb, respectively. By comparing with a conventional spherical structure, the leaf-like micro-/nanostructure was revealed to possess an improved ability for diffusion and adsorption/desorption. The structure could be generally significant for developing some other novel materials which possess a morphology inspired from nature for specific applications, such as sensors, energy transfer and storage devices, and catalysts.