The Preparations Of Fe₂O₃-based Nanomaterials And Their Sensors’ Properties Researches

In the recent years, the pollution of environment problem attracts more and more attentions with the rapid developing of Chinese industry. Monitoring the inflammable,explosive and toxic gases plays a very important role in peoples’ life. Hence, the research and development of gas sensors for monitoring these harmful gases became a hot topic. One of the important part of gas sensors is gas sensing material, and the species and structures of the gas sensing materials have a crucial influence on the performance of gas sensors. At present, low dimension and porous gas sensing nanomaterials became a hot topic with the development of nanomaterials. The studies have indicated that porous one-dimension nanomaterials have a high specific area and electronics conduction properties. And these advantages are benefit to gas sensing properties. Fe₂O₃ is a common, cheap and good physicochemical property semiconductor material. And it has been widely used in the fields of battery, catalyst,photoelectric solution, magnetic, gas sensor and so on. In the recent years, Fe₂O₃ has been used in gas sensors to test many gases. However, pure Fe₂O₃ has a poor gas sensing property, and couldn’t meet people’s requirements. So researchers usually make Fe₂O₃ a low dimension, pore and doping to improve its gas sensing property.In this paper, one-dimension Fe₂O₃ nanomaterials are prepared via electrospinning method. In the mean of adjusting precursor solutions to obtain one-dimension Fe₂O₃ nanomaterials with good gas sensing property, different structure and doping. And the Fe₂O₃ nanomaterials are made for excellent performance of gas sensors. Specific content as follows:1 Pure and Sm-doped Fe₂O₃ nanotubes with a diameter 90 nm are prepared via a typical electrospinning technology. The nanomaterials are made for gas sensors, and the performances of the gas sensors are researched. The research indicate that the gas sensing properties of pure Fe₂O₃ nanotubes are improved bt doping Sm, remarkably.At the optimum operating temperature 240℃, the response of 3wt% Sm-doped Fe₂O₃ nanotubes is 33 to 50 ppm acetone, which is 13 times larger than that of pure Fe₂O₃ nanotubes. The lowest detection limit of acetone is 500 ppb to which the response is2.3. In addition, 3wt% Sm-doped Fe₂O₃ nanotubes exhibit good selectivity and long term stability.2 Pure and Nd-doped porous Fe₂O₃ nanotubes with a diameter 80 nm are prepared via a typical electrospinning technology. The nanomaterials are made for gas sensors, and the performances of the gas sensors are researched. The result shows that the Nd-doped porous Fe₂O₃ nanotubes performance a ultrahigh response to acetone.The response of Nd-doped porous Fe₂O₃ nanotubes is about 44 to 50 ppm acetone at the optimum operating temperature of 240℃, which is 17 times larger than that of pure porous Fe₂O₃ nanotubes. In addition, the Nd-doped porous Fe₂O₃ nanotubes possess good selectivity and long-term stability.3 Pure and Al₂O₃-doped Fe₂O₃ nanotubes are prepared via a typical electrospinning technology. The nanomaterials are made for gas sensors, and the performances of the gas sensors are researched. The research of the samples gas sensing properties demonstrates that the ethanol sensing properties of Fe₂O₃ nanotubes are enhanced by doping Al₂O₃, remarkably. The response value of Al₂O₃-doped Fe₂O₃ nanotubes to 50 ppm ethanol is 41.8 at the optimum operating temperature 240℃. And the lowest detection limit is 300 ppb, to which the response value is about 2. The response of pure Fe₂O₃ nanotubes is 4. In addition, the Al₂O₃-doped Fe₂O₃ nanotubes possess good selectivity and long-term stability.4 Pure and Pr-doped Fe₂O₃ nanotubes are prepared via a typical electrospinning technology. The nanomaterials are made for gas sensors, and the performances of the gas sensors are researched. The researches of the gas sensing properties of the samples show that Pr-doped Fe₂O₃ nanotubes possess a better sensitive to ethanol than that of pure Fe₂O₃ nanotubes, and the response value of Pr-doped Fe₂O₃ nanotubes to10 ppm ethanol is 21.3 at the operating temperature 240℃. And the lowest detection limit is 300 ppb, to which the response value is about 2.1. The response of pure Fe₂O₃ nanotubes is 1.5 to 10 ppm ethanol. Moreover, Pr-doped Fe₂O₃ nanotubes show goodselectivity and long-term stability.