scholarly journals MoO3 Structures Transition from Nanoflowers to Nanorods and Their Sensing Performances

2021 ◽  
Author(s):  
Li-Bin Hu ◽  
Xin-Yu Huang ◽  
Shan Zhang ◽  
Xue Chen ◽  
Xian-Hui Dong ◽  
...  
Keyword(s):  
Material Science ◽  
Annealing Temperature ◽  
Physicochemical Characteristics ◽  
Growth Strategies ◽  
Oxide Semiconductors ◽  
Sensing Material ◽  
Volatile Organic ◽  
Gas Response ◽  
Calcined Temperature ◽  
Morphology Changes

Abstract Morphology transformation and crystal growth strategies of metal oxide semiconductors are extensive studied in material science recently, because the morphology and crystallinity of the nanomaterial have significant effect on the physicochemical characteristics. However, understanding the morphology changes of α-MoO3 induced by annealing temperature is still a challenge. Herein, the nanostructure transition of MoO3 induced by calcined temperature has been investigated through XRD and SEM method. It can be found that crystallization is highly dependent on the annealing temperature. In addition, the MoO3 nanoflowers can change into nanosheets at 500 ºC. Afterwards, the nanosheets turn into microrods, especially at 900 ºC due to the growth of MoO3 crystal. On the other hand, MoO3 is a traditional sensing material, which is sensitive to many volatile organic compounds. Thus, the sensing performances of various MoO3 nanostructures were measured. Compared with MoO3 nanoflowers and microrods. The MoO3 nanosheets based sensor has excellent sensing performance towards ethanol, and the maximum gas response value is 8.06.

scholarly journals Selectivity of Tungsten Oxide Synthesized by Sol-Gel Method Towards Some Volatile Organic Compounds and Gaseous Materials in a Broad Range of Temperatures

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 523 ◽  
Author(s):  
Simonas Ramanavičius ◽  
Milda Petrulevičienė ◽  
Jurga Juodkazytė ◽  
Asta Grigucevičienė ◽  
Arūnas Ramanavičius
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Sol Gel ◽  
Temperature Dependent ◽  
Sensing Systems ◽  
Sensing Material ◽  
Operational Temperature ◽  
Volatile Organic ◽  
Different Gases

In this research, the investigation of sensing properties of non-stoichiometric WO3 (WO3−x) film towards some volatile organic compounds (VOC) (namely: Methanol, ethanol, isopropanol, acetone) and ammonia gas are reported. Sensors were tested at several temperatures within the interval ranging from a relatively low temperature of 60 up to 270 °C. Significant variation of selectivity, which depended on the operational temperature of sensor, was observed. Here, the reported WO3/WO3–x-based sensing material opens an avenue for the design of sensors with temperature-dependent sensitivity, which can be applied in the design of new gas- and/or VOC-sensing systems that are dedicated for the determination of particular gas- and/or VOC-based analyte concentration in the mixture of different gases and/or VOCs, using multivariate analysis of variance (MANOVA).

A Novel Tungsten Trioxide Based Gas Sensor for Indoor Formaldehyde Detection

2021 ◽  
Vol 16 (3) ◽  
pp. 363-367
Author(s):  
Gaoqi Zhang ◽  
Fan Zhang ◽  
Kaifang Wang ◽  
Tao Tian ◽  
Shanyu Liu ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Gas Sensor ◽  
Indoor Air ◽  
Gas Sensing ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sensing Material ◽  
Transmission Electron ◽  
Gas Sensing Properties ◽  
Gas Response

Accurate and real-time detection of formaldehyde (HCHO) in indoor air is urgently needed for human health. In this work, a ceramic material (WO3·H2O) with unique structure was successfully prepared using an efficient hydrothermal method. The crystallinity, morphology and microstructure of the as-prepared sensing material were analyzed by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM) as well as transmission electron microscope (TEM). The characterization results suggest that the as-prepared sample is composed of square-like nanoplates with uneven surface. Formaldehyde vapor is utilized as the target gas to investigate gas sensing properties of the synthesized novel nanoplates. The testing results indicate that the as-fabricated gas sensor exhibit high gas response and excellent repeatability to HCHO gas. The response value (Ra/Rg) is 24.5 towards 70 ppm HCHO gas at 350 °C. Besides, the gas sensing mechanism was described.

A Strategy to Improve O2 Gas Response of La-SnO2 Nanofibers Based Sensor through Temperature Modulation

2019 ◽  
Vol 944 ◽  
pp. 657-665
Author(s):  
Ya Xiong ◽  
Hui Li ◽  
Tian Chao Guo ◽  
Qing Zhong Xue
Keyword(s):  
Gas Sensors ◽  
Gas Sensing ◽  
Operation Mode ◽  
Temperature Modulation ◽  
Oxide Semiconductors ◽  
Oxygen Ions ◽  
Isothermal Test ◽  
Sensor Temperature ◽  
Heating Energy Consumption ◽  
Gas Response

Generally sensing mechanisms of gas sensors based on metal-oxide semiconductors greatly depend on temperature, suggesting temperature modulation can be applied as a vital method to effectively enhance the sensor response. In this paper, we reported a strategy of quick-cooling operating temperature mode in the course of gas sensing process to elevate the O2 gas response while maintaining low heating energy consumption. La-SnO2 nanofibers synthesized by electrospinning were chosen as gas sensing materials. The O2 gas responses by employing quick-cooling operation mode are significantly improved compared with those obtained by traditional isothermal test. The improved O2 response is contributed to a higher coverage of negatively charged oxygen ions as a result of quick cooling. Our research offers a facile route to detect gas at low temperature with high response. More importantly, the strategy demonstrated here could also be extended to other gas sensor as long as its gas response is related to the sensor temperature.

Al-doped GeS nanosheet as a promising sensing material for O-contained volatile organic compounds detection

2020 ◽  
Vol 527 ◽  
pp. 146797 ◽  
Author(s):  
Kaiwen Pu ◽  
Xianying Dai ◽  
Yuyu Bu ◽  
Runqiu Guo ◽  
Wenluo Tao ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Sensing Material ◽  
Volatile Organic

NiO nanosheets assembled into hollow microspheres for highly sensitive and fast-responding VOC sensors

RSC Advances ◽  
2015 ◽  
Vol 5 (98) ◽  
pp. 80786-80792 ◽  
Author(s):  
Qing Li ◽  
Nan Chen ◽  
Xinxin Xing ◽  
Xuechun Xiao ◽  
Yude Wang ◽  
...  
Keyword(s):  
Organic Compound ◽  
Volatile Organic Compound ◽  
Hollow Microspheres ◽  
Highly Sensitive ◽  
Volatile Organic ◽  
Gas Response ◽  
Nio Nanosheets

NiO hollow microspheres synthesized through a SiO2 spheres template-assisted approach show a very good gas response towards volatile organic compound vapors.

Enhanced Gas Sensing of Tin Dioxide Based Sensor for Indoor Formaldehyde Application

2021 ◽  
Vol 16 (2) ◽  
pp. 337-342
Author(s):  
Gaoqi Zhang ◽  
Fan Zhang ◽  
Kaifang Wang ◽  
Shanyu Liu ◽  
Ying Wang ◽  
...  
Keyword(s):  
Gas Sensors ◽  
Tin Dioxide ◽  
Gas Sensing ◽  
Fast Response ◽  
Sensing Material ◽  
Gas Sensing Properties ◽  
Recovery Times ◽  
Response And Recovery ◽  
Formaldehyde Sensing ◽  
Gas Response

Indoor formaldehyde detection is of great important at present. Using efficient solvothermal method, nanosheet-constructed and nanorod-constructed hierarchical tin dioxide (SnO2) microspheres were successfully synthesized in this work and used for the gas sensing material for indoor formaldehyde application. The as-prepared two kinds of SnO2 gas sensing materials were applied to fabricate the gas sensors and formaldehyde gas sensing experiments were carried out. The HCHO gas sensing tests indicate that the gas response of the nanosheet-constructed SnO2 microspheres is about 1.7 times higher than that of the nanorod-constructed SnO2 microspheres. In addition, both of the two SnO2 based gas sensors show almost fast response and recovery time to HCHO gas. For the nanosheet-constructed microspheres, the response value is estimated to be 32.0 at 350 °C to 60 ppm formaldehyde gas, while the response and recovery times are 7 and 5 s, respectively. The simple and efficient preparation method and improved gas sensing properties show that the as-synthesized hierarchical SnO2 microsphere that is constructed by a large amount of nanosheets exhibits significant potential application for the indoor formaldehyde sensing.

scholarly journals Effect of Working Atmospheres on the Detection of Diacetyl by Resistive SnO2 Sensor

2021 ◽  
Vol 12 (1) ◽  
pp. 367
Author(s):  
Andrea Gnisci ◽  
Antonio Fotia ◽  
Lucio Bonaccorsi ◽  
Andrea Donato
Keyword(s):  
Alcoholic Fermentation ◽  
Low Cost ◽  
Oxide Semiconductors ◽  
Response Recovery ◽  
Volatile Organic ◽  
Recovery Times ◽  
Quality Of Products ◽  
And Storage ◽  
Anaerobic Environment

Nanostructured metal oxide semiconductors (MOS) are considered proper candidates to develop low cost and real-time resistive sensors able to detect volatile organic compounds (VOCs), e.g., diacetyl. Small quantities of diacetyl are generally produced during the fermentation and storage of many foods and beverages, conferring a typically butter-like aroma. Since high diacetyl concentrations are undesired, its monitoring is fundamental to identify and characterize the quality of products. In this work, a tin oxide sensor (SnO2) is used to detect gaseous diacetyl. The effect of different working atmospheres (air, N2 and CO2), as well as the contemporary presence of ethanol vapors, used to reproduce the typical alcoholic fermentation environment, are evaluated. SnO2 sensor is able to detect diacetyl in all the analyzed conditions, even when an anaerobic environment is considered, showing a detection limit lower than 0.01 mg/L and response/recovery times constantly less than 50 s.

scholarly journals Hydrothermally growth of TiO2 Nanorods, characterization and annealing temperature effect

2021 ◽  
Vol 48 (3) ◽  
Author(s):  
Nada Falih M ◽  
◽  
Saleem Azara Hussain ◽  
Shawki Khalaf Muhammad ◽  
Adel H. Omran Alkhayatt ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Optical Properties ◽  
Surface Topography ◽  
Hydrothermal Method ◽  
Annealing Temperature ◽  
Tio2 Nanorods ◽  
Energy Band Gap ◽  
Conductive Glass ◽  
Photocatalytic Applications ◽  
Morphology Changes

Titanium dioxide TiO2 nanorods were successfully grown on conductive glass FTO substrate using the hydrothermal method at a temperature of 160 oC. Surface topography, structure, and optical characteristics were studied according to the influence of annealing temperature (450, 550, and 650) oC. The surface topography results reveal that the TiO2 had nanorods structure with a tetragonal shape, and the rod diameter increases from 84.2 nm to 116.6 nm with increasing the annealing temperature. The crystal structure of the grown TiO2 NRs exhibits a high crystallinity of polycrystalline nature with anatase and rutile phases. The preferential orientation was along (204) plane for anatase tetragonal structure. AFM image shows an intense edge, uniform surface morphology, and increased grain diameter with annealing temperature. The optical properties of TiO2 NRs were investigated, and the absorption edge shows a blue shifting as the annealing temperature increases when considering the crystallinity and morphology changes. The energy band gap was found to be lower than 3 eV, which can be attributed to the presence of anatase and rutile phases with an increment range from 2.72 to 2.86 nm alongside the increase in the annealing temperature. The results indicate that the adopted hydrothermal method and the synthesized TiO2 NRs were suitable for photovoltaic and photocatalytic applications.

scholarly journals Graphene-enhanced metal oxide gas sensors at room temperature: a review

2018 ◽  
Vol 9 ◽  
pp. 2832-2844 ◽  
Author(s):  
Dongjin Sun ◽  
Yifan Luo ◽  
Marc Debliquy ◽  
Chao Zhang
Keyword(s):  
Metal Oxide ◽  
Gas Sensors ◽  
Room Temperature ◽  
Gas Sensing ◽  
Metal Oxide Semiconductors ◽  
Oxide Semiconductors ◽  
Sensing Material ◽  
Metal Oxide Gas Sensors ◽  
Low Sensitivity ◽  
Sensing Performance

Owing to the excellent sensitivity to gases, metal-oxide semiconductors (MOS) are widely used as materials for gas sensing. Usually, MOS gas sensors have some common shortages, such as relatively poor selectivity and high operating temperature. Graphene has drawn much attention as a gas sensing material in recent years because it can even work at room temperature, which reduces power consumption. However, the low sensitivity and long recovery time of the graphene-based sensors limit its further development. The combination of metal-oxide semiconductors and graphene may significantly improve the sensing performance, especially the selectivity and response/recovery rate at room temperature. In this review, we have summarized the latest progress of graphene/metal-oxide gas sensors for the detection of NO2, NH3, CO and some volatile organic compounds (VOCs) at room temperature. Meanwhile, the sensing performance and sensing mechanism of the sensors are discussed. The improved experimental schemes are raised and the critical research directions of graphene/metal-oxide sensors in the future are proposed.

Sign in / Sign up

Export Citation Format

Share Document