Novel Fe2O3 hollow spheres with mesopores on the surface were first synthesized on a large scale by a facile and efficient hydrothermal process, without templates in the system. The samples were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and N2 adsorption−desorption. When the amorphous Fe2O3 hollow spheres were used as the photocatalytic material, they performed better than the nanocrystal samples. This synthetic procedure is straightforward and thus facilitates mass production of Fe2O3 hollow spheres.

The field-emission and current-voltage characteristics of individual W 5 O 14 nanowires were studied using a transmission electron microscope and a field-emission microscope. The individual W 5 O 14 nanowires made good ohmic contacts with W and Pt at room temperature and had excellent field-emission properties. The field-emission measurements showed that a current as high as 35 µA can be extracted from a single nanowire. A reduced angular current density of 28.7 nAsr -1 V -1 was obtained from a W 5 O 14 nanowire with a sharp tip. These results suggest that W 5 O 14 nanowires might be a realistic candidate as the source for a low-energy electron beam.