| The definition of sensors in national standard of the People’s Republic of China(GB7665-87) is a kind of device or equipment which can detect physical signal and convert into useable electrical signal by a regular pattern. The devices contain sensing element and transition element. Gas sensors are important branch of sensors, and were widely used in the field of air outdoor/indoor environmental monitoring, pollution sources monitoring, industrial/peoplesafety and non-invasive medical care. In order to expand application field and potential application value, the sensentivity properties of gas sensor such as response, selectivity, response tme, recovery time and long term stability should be enhanced. As the core part of gas sensor, sensitive material greatly impacts the performance of gas sensors. So design and develop novel nanomaterials are play important role in enhancing the sensing performance of gas sensors. With the development of electrospinning, the one-dimensional nanomaterials have commanded people’s extensive concern and attention in recent years, which have the advantages of good permeability, high specific surface area and large length to diameter ratio. In this paper, we have comprehensively investigated the sensing properities of gas sensors based on one-dimensional metal oxide nanomaterials. And explore the relationship between composition, morphology and doping, which enhanced the gassensing properties ofsensing materials, such as response, selectivity, response/recovery time and long term stability. The main research contents in this paper are summarized as follows:(1) Uniform WO3 nanofibers were synthesized by electrospinning, the morphology and sensing properities were changed by doping La2O3. The gas sensors based on La2O3-doped WO3 nanofibers, in which the molar ratio of La3+:W6+ is 3:100, exhibit highest response toward 100 ppm acetone, having a response about 12.7, which is almost 2 times higher than that of sensor based on pure WO3 nanofibers. But the recover time and the limit of detection should be improved.(2) On the basis of La2O3-doped WO3 nanofibers, In2O3-doped WO3 nanofibers were synthesized by electrospinning. The SEM results show that the surfaces are rougher with the increment of In2O3 doping. The sensors based on In2O3-WO3 nanofibers, in which the molar ratio of In2O3:WO3 is 1.5:100, exhibits the largest response toward 50 ppm acetone among those nanofibers, having a response about 12.9- 50 ppm acetone, which is almost 2.5 times higher than that of sensor based on pure WO3 nanofibers at the optimum operating temperature.(3) Porous W6+ doped Ni O nanotubes were synthesized by electrospinning, the morphologies and sensing properities were changed by doping W6+. The SEM results show that the diameter of nanotubes is 90 nm, the size of grain is smaller and the specific surface area is increase with the increment of W doping. The gas sensors based on W6+-doped Ni O nanotubes, in which the molar ratio of W6+:Ni2+ is 2:100, exhibit highest response toward 200 ppm xylene, having a response about 8.74, which is almost 3.3 times higher than that of sensor based on pure Ni O nanotubes. But the response time, recover time, response and the limit of detection should be improved.(4) On the basis of W6+-doped Ni O nanotubes, Cr3+-doped Ni O nanotubes were synthesized by electrospinning. The gas sensors based on Cr3+-doped Ni O nanotubes, in which the molar ratio of Cr3+:Ni2+ is 3:100, exhibit highest response toward 50 ppm xylene, having a response about 88, which is almost 63 times higher than that of sensor based on pure Ni O nanotubes. Cr3+ doped Ni O nanotubes have the following advantages: First, high response. The response to 200 ppm xylene is 695, which is much higher than W6+-doped Ni O nanotubes. Second, fast response and recover time. The response and recover time are 144 s and 50 s, respectively. Third, the limit of dection is low. The LOD of gas sensors which based on Cr3+-doped Ni O nanotubes is 5ppm. Forth, the selectivity is good. The distinguishability of gassensors(Rxylene/Rethanol) is 9.
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