Effect Of Stiring Rate During Sol-Gel Method On Microstructure And Phase Change Of TiO2

Abstract

Chemical sensor is an effective way to detect pollutant, toxic and combustible gases. Therefore, a lot of effort has been focused on this field. The conventional metal oxide gas sensors are activated by heat, generally working at a temperature between 200 and 400o C, which limits their applications to flammable gases and some special conditions such as being as biosensors. Recently, many efforts aimed to improve gas sensor performance. The research on nanostructures, giving rise to an increased specific surface area, has brought to significant improvement in sensitivity. Additionally, theoretical models have been developed to justify the size-dependent behaviour of the gas response of nanocrystalline oxides. Moreover, addition of catalysts and/or dopants has been used to obtain a better selectivity; however, stable chemoresistive gas sensors can be obtained only by preparing materials and sensing layers with well controlled morphological, structural and electrical properties.Based on X-Ray diffraction (XRD) analysis on solgel resulted

of stirring rate 600 rpm, 700 rpm and 800 rpm, it shown that there are phase changed anatase phase (raw material) into unstable phase orthorombic titanium oxide sulfate (TiOSO ). After sintering at 700 ͦ C, there are phase transformation from titanium oxide sulfat (TiOSO 4 into anatase titanium dioxide (TiO ) again. However, the combination of stiring rate 700 rpm and 800 rpm followed by sintering at 700 ͦ C hopefully can reduce titanium cation or vacancy cation. Based on scanning electron microscope (SEM) analysis, as-received powder titanium dioxide had circularshape

particle. After sol-gel method in titanium dioxide ceramic material which dissolved with 98 % sulfat acid (H 2 SO ) produce titanium dioxide microstructure capsul shape, look like rice particle. Stiring rate on 700 rpm and 800 rpm can reduce the size up to 120 nm. Stiring rate on 600 rpm followed sintering at 700 4 o C resulted large porosity up to 20 μm, stiring rate 700 rpm had resulted porosity size up to 5 μm and 800 rpm had resulted homogeneity. It can conclude that best product is stirring rate 800 rpm followed by sintering.