Preparation And Properties Of Anatase TiO₂ Nanocube And NS TiO₂/SiC Ultrafine Fibers

TiO₂ has drawn much attentions as functional materials due to its chemical stability,low cost and friendly environment.Recently,some papers have reported that different crystal face of TiO₂ has a great impact on the gas sensor property.Herine,I prepared different ratio of（001）crystal face for TiO₂ through adjusting the hydrothermal reaction parameters and explored the gas sensor properties.The final results confirmed that（001）crystal face of TiO₂ play a vital role on the sensor property.Addtionally,we also fabricated the hierarchical NS-TiO₂/SiC ultrafine fibers through the hydrothermal method.The gas sensor properties were also investigated.Different morphology and crystal face of TiO₂ can be controlly synthesized by adjusting the reactant concentration and reaction time.The results prove that the gas sensitivity for ethanol,acetone and toluene will enhance with the incease of the exposue ratio of（001）facet.Furthermore,the sensor property decreased after destroying the（001）face of TiO₂,further confirming that（001）face in TiO₂ plays the main role on the gas sensor property.The size of TiO₂ nanosheets on the SiC ultrafine fibers is about 500×500×40 nm.The phase of TiO₂ nanosheets is rutile.The exposure ratio of（001）face is 86.2%.The formation mechanism for different morphology of TiO₂ is related to the existence of Cl^-and F^-,which will determine the growth direction of TiO₂.According to the experimental results,NS-TiO₂/SiC shows the biggest sensitivity of 38.2 for acetone,which is 1.37 times higher than pure NS-TiO₂（27.8）.The obvious enhancement of sensitivity originates from the synergistic effect of high exposure of（001）facet,nano heteojunction and hierarchical structure.This work will provide a new insight for the design and preparation of high temperature sensors for the harsh environments.