Zinc oxide (ZnO) nanoplates and tungsten trioxide (WO3) nanorods were synthesized by hydrothermal treatment from zinc nitrate/potassium hydroxide and sodium tungstate/hydrochloric acid, respectively. The structure, morphology and compositions of the as-prepared WO3/ZnO nano-composites were characterized by x-ray diffraction, field emission scanning electron microscopy and energy dispersive spectroscopy. The obtained ZnO nanoplates have regular shape, single-crystal wurtzite structure with the thickness of 40 nm and 200 versus 400 nm in lateral dimensions. The WO3 nanorods possess the average diameter of 20 nm and the length of approximately 120 nm which were distributed on the surfaces of ZnO nanoplates. The WO3/ZnO nano-composites were prepared by grinding WO3 nanorods powder with ZnO nanoplates powder in various weight ratios (1:2, 1:1 and 2:1). The NH3 gas sensing properties of WO3/ZnO nano-composites were examined through the electrical resistance measurement. The gas sensing performance of the WO3/ZnO composite with weight ratio of 1:1 was better compared with that of other samples. For this sample, the maximum response to 300 ppm NH3 was 24 at the operating temperature of 250 °C. In addition, the gas sensing mechanism of the WO3/ZnO composites was discussed.

SnO 2 nanorods were successfully prepared by a hydrothermal method using tin chloride, liquid ammonia, sodium hydroxide and cetyltrimethyl ammonium bromide (CTAB) as starting materials. Structural properties and surface morphologies of the SnO 2 nanorods were characterized by x-ray diffraction (XRD) and scanning electron microscopy (SEM). Experimental results showed that the diameter of the nanorods is in the range of 100–300 nm with a length of several micrometers. The hydrothermal treatment temperature was found to play an important role in determining the morphology and diameter of the SnO 2 nanorods. Possible growth mechanisms of SnO 2 nanorods were proposed.

CuO, Al 2 O 3, Ag 2 O and La 2 O 3 doped on SnO 2 nanoparticles were successfully fabricated by a hydrothermal route at 200 °C for 3 h. The morphology and composition were characterized by field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and energy dispersive x-ray analysis (EDX). The results showed that the particle size is 6–8 nm without other impurities. The influence of CuO with a concentration of 0.5–3wt%, which was doped on sol SnO 2 5wt% by hydrothermal and vibration technique, was discussed. In addition, the gas sensitivity experiment of samples to 1% LPG in the temperature range of 230–430 °C indicated the improvement in sensitivity and response time. In particular, the SnO 2 sol suspension 5wt% doped with CuO 2wt% showed the best sensitivity at 330 °C.

One-dimensional nanostructures such as nanowires have been extensively investigated as a promising type of material for applications of nanoscale technology. The fabrication of single-nanowire devices are consequently important and interesting. This study introduced a feasible method for growing CuO nanowires on Cu foils. The nanowires had diameters of 10~150 nm and lengths of more than 7 μm and were grown by means of thermal oxidation in a vacuum. They were entirely and uniformly grown over the Cu foil surfaces and could be extracted and dispersed in an ethanol solution for further purposes. In addition, a simple fabrication method for realizing device functionality from a single CuO nanowire was reported.Fabricated devices were carefully checked by field-emission scanning electron microscopy (SEM). The probability of the realization of a single-CuO-nanowire device relative to that of all other types was estimated to be around 25%. Finally, the I-V characteristics of the devices were analyzed.