“…Since Law et al reported that the photochemical sensor of individual SnO 2 nanoribbons showed fast and sensitive response for detecting ppm-level NO 2 at room temperature for the first time [15], the exploration of gas sensors focused on various 1D SnO 2 nanostructures, such as nanowires [16], nanorods [17], nanobelts [18], nanotubes [19], and so on, have been attracting a great deal of interest for the detection of volatile organic compound vapors (VOCs). However, these products are usually difficult to effectively play its advantages for their random orientation.…”
Layered Eu-doped SnO2 ordered nanoarrays constructed by nanorods with 10 nm diameters and several hundred nanometers length were synthesized by a substrate-free hydrothermal route using alcohol and water mixed solvent of sodium stannate and sodium hydroxide at 200 °C. The Eu dopant acted as a crystal growth inhibitor to prevent the SnO2 nanorods growth up, resulting in tenuous SnO2 nanorods ordered arrays. The X-ray diffraction (XRD) revealed the tetragonal rutile-type structure with a systematic average size reduction and unit cell volume tumescence, while enhancing the residual strain as the Eu-doped content increases. The surface defects that were caused by the incorporation of Eu ions within the surface oxide matrix were observed by high-resolution transmission electron microscope (HRTEM). The results of the response properties of sensors based on the different levels of Eu-doped SnO2 layered nanoarrays demonstrated that the 0.5 at % Eu-doped SnO2 layered nanorods arrays exhibited an excellent sensing response to methanal at 278 °C. The reasons of the enhanced sensing performance were discussed from the complicated defect surface structure, the large specific surface area, and the excellent catalytic properties of Eu dopant.
“…Since Law et al reported that the photochemical sensor of individual SnO 2 nanoribbons showed fast and sensitive response for detecting ppm-level NO 2 at room temperature for the first time [15], the exploration of gas sensors focused on various 1D SnO 2 nanostructures, such as nanowires [16], nanorods [17], nanobelts [18], nanotubes [19], and so on, have been attracting a great deal of interest for the detection of volatile organic compound vapors (VOCs). However, these products are usually difficult to effectively play its advantages for their random orientation.…”
Layered Eu-doped SnO2 ordered nanoarrays constructed by nanorods with 10 nm diameters and several hundred nanometers length were synthesized by a substrate-free hydrothermal route using alcohol and water mixed solvent of sodium stannate and sodium hydroxide at 200 °C. The Eu dopant acted as a crystal growth inhibitor to prevent the SnO2 nanorods growth up, resulting in tenuous SnO2 nanorods ordered arrays. The X-ray diffraction (XRD) revealed the tetragonal rutile-type structure with a systematic average size reduction and unit cell volume tumescence, while enhancing the residual strain as the Eu-doped content increases. The surface defects that were caused by the incorporation of Eu ions within the surface oxide matrix were observed by high-resolution transmission electron microscope (HRTEM). The results of the response properties of sensors based on the different levels of Eu-doped SnO2 layered nanoarrays demonstrated that the 0.5 at % Eu-doped SnO2 layered nanorods arrays exhibited an excellent sensing response to methanal at 278 °C. The reasons of the enhanced sensing performance were discussed from the complicated defect surface structure, the large specific surface area, and the excellent catalytic properties of Eu dopant.
“…When the temperature increases above 325 C, the sensitivity gradually decreases due to progressive desorption of all oxygen ionic species previously adsorbed. 7 The maximum sensitivities are 456, 50, 436, 950, and 650 for samples 1, 2, 3, 4, and 5 to 300 ppm ethanol, respectively (see Table I). Among these samples, hollow microspheres and nanosheets calcined at 600 C (sample 5) show the highest sensitivity to ethanol with value of 950.45.…”
Section: Sensing Propertiesmentioning
confidence: 97%
“…5 So, the controlled synthesis of the SnO 2 nanostructures is very important for their fundamental and technological applications. To date, various structural and morphological forms of SnO 2 nanomaterials have been fabricated, including nanoparticles, nanorods, nanoribbons, nanowires, nanotubes, nanodisk, nanoboxes, hollow micro/nanospheres [6][7][8][9][10][11][12][13][14] and so on.…”
In this study, we synthesized tetragonal-phase SnO2 with a variety of well-crystallized morphologies as solid microspheres, hollow microspheres and mixture of hollow microspheres and nanosheets via the hydrothermal method. The synthesized samples were characterized with XRD, SEM, and BET. SnO2 hollow microsphere structures have been hydrothermally synthesized by using urea and SnCl2 as raw materials. With the addition of cetyltrimethylammonium bromide (CTAB), nanostructures with morphologies of hollow microspheres and nanosheets were obtained. Also, when CTAB was added in the reaction solution without urea, SnO2 microsphere with a solid interior composed of nanoparticles were obtained. A possible formation mechanism of these samples was briefly discussed. The gas sensing properties of sensors based on these samples were investigated. The result revealed that sample with morphology of hollow microsphere and nanosheet calcined at 600 degrees C showed the highest sensitivity to ethanol due to the special morphology and absence of SnO phase.
“…These reaction-produced electrons may decrease the resistance, which results in the rise of output voltage when sensor is exposed in the gas. [8][9][10] On the other hand, the electron-hole pairs, which are generated by the UV light, can increase the conductivity of both bulk and grain interior, which consequently modifies the surface potential. In addition, the free electrons generated by the oxygen adsorption give rise to the broadening of inversion region, which correspondingly increases sample resistance.…”
TiO 2 -doped SnO 2 nanopowder is synthesized via a sol-gel method and characterized by atomic force microscopy and X-ray diffraction. Using this nanopowder, we have fabricated a novel semiconductor gas sensor that is sensitive to UV light illumination. We find that gas-sensing properties of TiO 2 -doped SnO 2 sensor can be enhanced significantly under the exposure of UV light. The sensor exhibits a high sensitivity of 25 and rapid response-recovery times of 8 s and 24 s, respectively, under an ethanol gas of up to 100 ppm at room temperature (323 K). This suggests the possibility of development of a gas sensor for detecting ethanol at room temperature.
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