| The properties of materials depend on not only the chemical composition of the materials, but also the size, surface state and structures, etc. Therefore, synthesis of nanomaterials with controlled size has attracted much attention of the material researchers. Ionic liquid has many properties which could be used to synthesize new kinds of nanomaterials that can not be synthesized by traditional methods, thus it can open up a new way of the synthesis of nanomaterials. Compared with conventional gas-sensing materials, nanomaterials have the irreplaceable advantages:First, nanomaterials have large specific surface areas, which could provide large amounts of gas channels to improve the sensitivity; Second, working temperature is reduced greatly that can decrease the energy consumption; Third, the size of the sensor can be reduced substantially. The metal oxide nanomaterials have the characteristics of high sensitivity, fast response and recovery, wide measuring range, especially low cost, etc. So the research of the metal oxide nanomaterials has great significance.In this paper, we synthesize zinc oxide (ZnO), tin oxide (SnO2), and copper oxide (CuO) nanomaterials with the assistance of ionic liquids. The products are analyzed, characterized and tested by X-ray diffractometer, scanning electron microscope (SEM), transmission electron microscope (TEM) and gas-sensing test system, etc. The influence factors of metal oxide nanostructures are discussed, and we illuminate the unique growth mechanism of the products with the assistance of ionic liquid. We use WS-30A gas-sensing test system to examine the gas-sensing performance (sensitivity, response and recovery time, etc.) of the sensors made by the as-prepared metal oxide powders, and explore the working mechanism of the gas sensors. The following are the detail contents:(1) Nanostructured ZnO particles are synthesized from an ionic liquid precursor benzyltrimethylammonium hydroxide (BTMAH). The influence of zinc salt concentration and the water amount on the ZnO final products is investigated, and the growth mechanism of the ZnO products with the assistance of BTMAH is uncovered. According to the results of gas-sensing test, the optimum working temperture to ethanol is240℃. The sensors exhibit good response to ethanol, even at low concentration. Also, they own the advantages of fast response and good stability, which have great significance to the development of gas sensors.(2) The SnO2particles with nanorod subunits are synthesized using conventional1-butyl-3-methylimidazodium chloride ([BMIM]Cl). The effects of reaction time and ionic liquid concentration are studied. Based on the research of growth mechanism, the ionic liquid [BMIM]Cl could change the inherent crystal growth behavior of SnO2and plays an important role in the formation of nanorod-assembled spherical particles. According to the study of gas sensors, the product synthesized in10h shows higher sensitivity. It is found that the as-prepared SnO2particles exhibit good response to different gases, which could be used for multi-type gas detections.(3) The CuO nanoplates are successfully synthesized with the assistance of an ionic liquid precursor benzyltrimethylammonium hydroxide (BTMAH). The effects of copper salt concentration and ionic liquid concentration on the morphologies are investigated. It is found that the viscosity of the mixture of water and ionic liquid has a signficant impact for the formation of the CuO nanoplates. CuO sensors exhibit good sensitivity, rapid response to various gases. Cyclic voltammogram test shows that the CuO nanoplates have excellent electrocatalytic properties to H2O2. |
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