Synthesis of Pearl-like NiO Nanoparticles-Functionalized In2O3 Nanonicicles with High Humidity Gas Sensing Property for Room Temperature Gas Sensor Application

• Main Authors: Ou-Hsiang Lee, 李翺翔
• Other Authors: Wen-Jea Tseng
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/25569591660908453809

碩士 === 國立中興大學 === 材料科學與工程學系所 === 103 === Conquering humidity influence on the gas sensing property at room temperature has been a major challenge in applied gas sensor device. Herein, we report a multi-functional hybrid system consisting of pearl-like NiO nanoparticles funtionalized on In2O3 nanoicicles by thermal vapor transport and chemical wet approach with tailored sensing properties. In this report, we demonstrate a novel structure of In2O3 nanoicicles with intrigued and sophisticated morphology. The growth mechanism of the In2O3 nanoicicles was investigated and discussed by observing structural evolution during the synthesis processes. The growth mechanism of the In2O3 nanoicicles can be ascribed to Au-catalytic VLS mechanism along [123] direction for the axial growth and VS mechanism for the lateral growth. As the axial growth rate was much faster than the lateral growth, resulted in the evolution of tapered nanoicicles. Pearl-like NiO, on the other side, was controlled and synthesized successfully with a radius 5 nm well distributed on the In2O3 backbone via chemical wet approach. The NiO-functionalized In2O3 nanoicicles (NiO/In2O3) with p-n junction on the contact bridge enhanced surface area and exhibited a remarkable sensing property as well as a selective detection toward NO2 gases owing to the transport behavior of the electron conduction channel. When exposed to NO2 gases with concentration of 30, 15, and 3 ppm, NiO/In2O3 exhibited a remarkable sensing performance with response of 46.6, 8.5, and 3.35 at 100˚C, and a room temperature sensing performance with response of 4.34, 2.1 and 1.76 respectively. In2O3 nanoicicles on the other hand, changed the resistance followed the same trend but with the response of 6.7, 3.56 and 3.01 at 100˚C, and a room temperature sensing performance with response of 2.51, 2.01 and 1.4 respectively. Furthermore, humidity dependence of the gas sensing property was reduced since the presense of NiO can minimize the humidity influence and eventually provided a promising gas sensing property for the application of room temperature gas sensor device.