One-step synthesis and gas sensing properties of hierarchical Cd-doped SnO2 nanostructures

The hierarchical undoped and Cd-doped SnO2 nanostructures had been synthesized via a low-cost and environmentally friendly hydrothermal route. The morphology and structure of the as-prepared product were characterized by X-ray diffraction (XRD), field-emission electron microscopy (FESEM), and transmission electron microscopy (TEM). The images of field-emission electron microscopy and transmission electron microscopy showed that pure and Cd-doped SnO2 hierarchical architectures were built from one-dimensional nanorods. X-ray diffraction (XRD) of the doped samples revealed that Cd incorporation led to lattice deformation without destroying the original crystal structure. Gas sensors based on undoped and Cd-doped SnO2 nanorods were fabricated, and their gas sensing properties were tested for various gases. The 3.0 wt% Cd-doped SnO2 based sensor showed excellent selectivity toward H2S at the operating temperature 275 °C, giving a response of about 31–10 ppm, which was about 22 times higher than that of sensor based on pure SnO2.