| Other Abstract | Hollow or porous materials have recently attracted considerable attention due to their specific structure with low density, high specific surface in chemical sensor, drug delivery and photocatalysis. As a very important n-type wide-band gap (3.6 eV) semiconductor, In2O3 has been widely used in solar cells, flat panel displays, gas detectors, etc, owing to its high electric conductance, high transparency to visible light, and the strong interaction between certain poisonous gas molecules and In2O3 surfaces. Because of the size and shape-dependent properties, controllable growth and mechanism studies of hollow or porous In2O3 with different morphologies are important. In this work, different morphologies of porous indium-oxide (In2O3) nanomaterials, including hollow spheres and hollow nanorods, have been successfully prepared by hydrothermal process. The main works can be summarized as follows:
First In2O3 hollow microspheres were successfully synthesized by hydrothermal process in the system of saccharides and In(NO3)3 mixtures in combination with heat-treatment. The effects of saccharides amount, temperatures and reaction times have been explored. It is found that the wall-thick of the hollow spheres increases at first, then decrease with the reaction temperatures increased from 150 ℃, 180 ℃ to 210 ℃, and the maximum wall-thick was 150 nm when the temperatures was 180 ℃. Similarly, the gas sensing properties also present the same change trend with the amounts of saccharide changed from 2 g, 4 g to 8 g. The highest gas sending response to ethanol and formaldehyde was 90 and 72, respectively, when the products obtained from the system of 3 mmol (In2O3) and 4g saccharides.
Next this work focuses on the design and synthesis of mesoporous In2O3 nanotubes with hollow structures. So, a method for the preparation of mesoporous In2O3 nanotubes(the three-step method)was developed. Firstly, ZnO nanorods were prepared which acting as hard templates to hollow In2O3 structures; Then, In(OH)3 nanoparticles grown on the surface of ZnO nanorods, and followed by the formation of mesoporous In2O3 shell on ZnO nanorods by heat-treatment at 600 ℃; Finally, acidic etching was adaped to remove the ZnO nanorods to form hollow structured In2O3 nanotubes. The influence factors on the morphologies, gas sensing properties, and aspect ratios of In2O3 hollow nanotubes, such as deposition times, concentration of acidic, were investigated. The results show that the optimum fa... |
