Simple Synthesis of Mesoporous SnO2 Microspheres and their Gas Sensing Properties

2014 ◽  
Vol 1044-1045 ◽  
pp. 96-99
Author(s):  
Zhi Peng Sun ◽  
Yi Lu
Keyword(s):  
Electron Microscope ◽  
Gas Sensing ◽  
Resorcinol Formaldehyde ◽  
X Ray ◽  
Sensing Properties ◽  
Transmission Electron ◽  
Gas Sensing Properties ◽  
Sensitivity And Selectivity ◽  
20 Nm ◽  
Tin Tetrachloride

In this work, uniform mesoporous SnO2microspheres have been prepared via a facile and scalable method using tin tetrachloride pentahydrate (SnCl4·5H2O) and resorcinol-formaldehyde gel (RF gel) as starting materials. Furthermore, the structure and morphology of the as-prepared product were characterized by scanning electron microscope (SEM), Transmission electron microscope (TEM) and X-ray diffractometer (XRD). The results revealed that as-synthesized microspheres were around 500 nm in size and composed of large amount of SnO2nanoparticles with diameters of 10-20 nm. Gas sensors based on mesoporous SnO2microspheres were fabricated, and their gas sensing properties were tested for response to methane, butane, H2and CO gas. The sensor exhibited better sensitivity and selectivity to H2vapors at 300 °C than that of the conventional SnO2materials. The enhancement in gas sensing properties was attributed to their unique nanostructures.

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.

Synthesis of Al Doped ZnO with a Novel Rice Microstructure by Hydrothermal Process and Analysis of their Gas Sensing Properties

2014 ◽  
Vol 809-810 ◽  
pp. 724-730
Author(s):  
Zan Li ◽  
Wei Qin ◽  
Xiao Hong Wu
Keyword(s):  
Electron Microscopy ◽  
Gas Sensing ◽  
Hydrothermal Process ◽  
Hexagonal Wurtzite Structure ◽  
X Ray ◽  
Sensing Properties ◽  
Transmission Electron ◽  
Gas Sensing Properties ◽  
Doped Zno ◽  
Hydrothermal Approach

Al-doped ZnO (AZO) powers with a novel rice-like morphology have been successfully synthesized through a simple and efficient hydrothermal approach, the products have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) with an energy-dispersive X-ray analyzer and transmission electron microscopy (TEM). It showed that all the samples presented an hexagonal wurtzite structure of high crystallinity, and the microstructure was composed of numerous dumbbells. Furthermore, the heater gas sensors were fabricated and an investigation of gas sensing properties has been conducted. The sensors showed good selectivity to ethanol comparing with NH3, SO2, CO and HCHO and possible mechanism was discussed. The Sensors based AZO powers exhibited high response values, reproducible response-recovery to ethanol 50-1800 ppm at 332°C.

Preparation and Gas Sensing Properties of Hierarchical Flower-Shaped Bi2WO6

2016 ◽  
Vol 69 (1) ◽  
pp. 107 ◽  
Author(s):  
Jingkun Xiao ◽  
Chengwen Song ◽  
Wei Dong ◽  
Yanyan Yin ◽  
Chen Li
Keyword(s):  
Photoelectron Spectroscopy ◽  
Gas Sensing ◽  
Fast Response ◽  
X Ray Diffraction ◽  
Fast Recovery ◽  
X Ray ◽  
Sensing Properties ◽  
Sensing System ◽  
Gas Sensing Properties ◽  
20 Nm

Hierarchical flower-shaped Bi2WO6 was obtained by a simple hydrothermal method. Morphology and structure of the Bi2WO6 were characterised by single electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and N2 adsorption techniques. Gas sensing properties of the Bi2WO6 sensor were investigated by a static gas-sensing system. The results show the as-synthesised flower-shaped product is pure orthorhombic Bi2WO6, which is composed of nanosheets with ~10–20 nm in thickness and hundreds of nanometres in planar size. At this optimal operating temperature of 300°C, the Bi2WO6 sensor exhibits ultra-fast response (1-2 s) and fast recovery time (6–12 s) towards ethanol detection, and high selectivity to other gases such as methanol, benzene, dichloromethane, and hexane.

The Characterization and Gas Sensing Properties of Polythiophene Coated V2O5 Nanotubes

2010 ◽  
Vol 654-656 ◽  
pp. 1154-1157 ◽  
Author(s):  
Yu Lu ◽  
Wei Jin ◽  
Wen Chen
Keyword(s):  
Electron Microscopy ◽  
Gas Sensing ◽  
In Situ Polymerization ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sensing Properties ◽  
Transmission Electron ◽  
Gas Sensing Properties ◽  
Higher Sensitivity

Polythiophene (PTP) coated V2O5 nanotubes were prepared by an in-situ polymerization of thiophene monomers in the presence of prepared V2O5 nanotubes. The nanotubes were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM), which proved the polymerization of thiophene monomer and the strong interaction between polythiophene and V2O5 nanotubes (VONTs). The gas sensing properties of PTP coated V2O5 nanotubes were studied at room temperature, which was found that PTP coated V2O5 nanotubes could detect ethanol with much higher sensitivity than pure VONTs. The sensing mechanism of PTP coated V2O5 nanotubes to ethanol is presumed to be the synergetic interaction between polythiophene (PTP) and V2O5 nanotubes.

scholarly journals Synthesis by Thermal Oxidation and Gas Sensing Properties of Fe2O3 Nanorods

2021 ◽  
Vol 31.2 (149) ◽  
pp. 84-88
Keyword(s):  
Thermal Oxidation ◽  
Gas Sensing ◽  
High Sensitivity ◽  
Measuring System ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sensing Properties ◽  
Oxide Nanorods ◽  
Gas Sensing Properties ◽  
Sensitivity And Selectivity

Iron oxide nanorods were synthesized by thermal oxidation of iron foil in the air at 300-500 oC. The scanning electron microscopy (SEM) and X-ray diffraction (XRD) were used to investigate the crystal structures and morphologies properties of the Fe2O3 nanorods. The gas sensing properties of the Fe2O3 nanorods were investigated using a static-gas measuring system in a range of 300-500 oC with the target gases of C2H5OH, CH3COCH3, LPG, and NH3. The results show that Fe2O3 nanorods possess high sensitivity and selectivity toward CH3COCH3. The highest response of 19 was recorded with 1000 ppm CH3COCH3 at the operating temperature of 400 oC.

scholarly journals Preparation and NH3 Gas-Sensing Properties of Double-Shelled Hollow ZnTiO3 Microrods

Sensors ◽  
2019 ◽  
Vol 20 (1) ◽  
pp. 46 ◽  
Author(s):  
Pi-Guey Su ◽  
Xiang-Hong Liu
Keyword(s):  
Electron Microscopy ◽  
Room Temperature ◽  
Gas Sensing ◽  
Strong Response ◽  
X Ray ◽  
Sensing Properties ◽  
Diallyldimethylammonium Chloride ◽  
Transmission Electron ◽  
Low Concentrations ◽  
Gas Sensing Properties

A novel double-shelled hollow (DSH) structure of ZnTiO3 microrods was prepared by self-templating route with the assistance of poly(diallyldimethylammonium chloride) (PDDA) in an ethylene glycol (EG) solution, which was followed by calcining. Moreover, the NH3 gas-sensing properties of the DSH ZnTiO3 microrods were studied at room temperature. The morphology and composition of DSH ZnTiO3 microrods films were analyzed using scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffractometry (XRD). The formation process of double-shelled hollow microrods was discussed in detail. The comparative gas-sensing results revealed that the DSH ZnTiO3 microrods had a higher response to NH3 gas at room temperature than those of the TiO2 solid microrods and DSH ZnTiO3 microrods did in the dark. More importantly, the DSH ZnTiO3 microrods exhibited a strong response to low concentrations of NH3 gas at room temperature.

Polyaniline/SnO2 Nanocomposite Sensor for NO2 Gas Sensing at Low Operating Temperature

2015 ◽  
Vol 14 (04) ◽  
pp. 1550011 ◽  
Author(s):  
A. Sharma ◽  
M. Tomar ◽  
V. Gupta ◽  
A. Badola ◽  
N. Goswami
Keyword(s):  
Thin Films ◽  
Gas Sensing ◽  
High Sensitivity ◽  
Morphological Properties ◽  
X Ray Diffraction ◽  
Chemical Route ◽  
Sensing Properties ◽  
Response Recovery ◽  
Transmission Electron ◽  
Gas Sensing Properties

In this paper gas sensing properties of 0.5–3% polyaniline (PAni) doped SnO 2 thin films sensors prepared by chemical route have been studied towards the trace level detection of NO 2 gas. The structural, optical and surface morphological properties of the PAni doped SnO 2 thin films were investigated by performing X-ray diffraction (XRD), Transmission electron microscopy (TEM) and Raman spectroscopy measurements. A good correlation has been identified between the microstructural and gas sensing properties of these prepared sensors. Out of these films, 1% PAni doped SnO 2 sensor showed high sensitivity towards NO 2 gas along with a sensitivity of 3.01 × 102 at 40°C for 10 ppm of gas. On exposure to NO 2 gas, resistance of all sensors increased to a large extent, even greater than three orders of magnitude. These changes in resistance upon removal of NO 2 gas are found to be reversible in nature and the prepared composite film sensors showed good sensitivity with relatively faster response/recovery speeds.

scholarly journals Preparation of Nanostructured SnO2-NiO Composite Semiconductor for Gas Sensor Applications

2021 ◽  
pp. 391-403
Author(s):  
S. Kumar ◽  
P. Gowthaman ◽  
J. Deenathayalan
Keyword(s):  
Gas Sensor ◽  
Composite Nanofibers ◽  
Volume Fraction ◽  
Gas Sensing ◽  
Precipitation Method ◽  
Response Sensitivity ◽  
X Ray ◽  
Sensing Properties ◽  
Working Temperature ◽  
Gas Sensing Properties

Electro spinning technology combined with chemical precipitation method and high-temperature calcination was used to prepare SnO2-NiO composite semiconductor nanofibers with different Sn content. Scanning electron microscope (SEM), X-ray diffractometer (XRD) and energy dispersive X-ray spectrometer (EDS) were used to characterize the morphology, structure and content of various elements of the sample. Using ethanol as the target gas, the gas sensing properties of SnO2-NiO nanofibers and the influence of Sn content on the gas sensing properties of composite nanofibers were explored. The research results show that SnO2-NiO composite nanofibers have a three-dimensional network structure, and the SnO2 composite can significantly enhance the gas sensitivity of NiO nanofibers. With increase of SnO2 content, the response sensitivity of composite fibers to ethanol gas increases, and the response sensitivity of composite nanofibers with the highest response to ethanol gas with a volume fraction of 100×10-6 at the optimal working temperature of 160℃ are13.4;It is 8.38 times the maximum response sensitivity of NiO nanofibers. Compared with the common ethanol gas sensor MQ-3 on the market, SnO2-NiO composite nanofibers have a lower optimal working temperature and higher response sensitivity, which has certain practical application value

A Formaldehyde Gas Sensor Based on Zinc Doped Lanthanum Ferrite

2013 ◽  
Vol 873 ◽  
pp. 304-310 ◽  
Author(s):  
Jin Zhang ◽  
Yu Min Zhang ◽  
Chang Yi Hu ◽  
Zhong Qi Zhu ◽  
Qing Ju Liu
Keyword(s):  
Gas Sensing ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Sensing Properties ◽  
Transmission Electron ◽  
Lanthanum Ferrite ◽  
Gas Sensing Properties ◽  
Recovery Times ◽  
Response And Recovery ◽  
Sensing Characteristics

The gas-sensing properties of zinc doped lanthanum ferrite (Zn-LaFeO3) compounds for formaldehyde were investigated in this paper. Zn-LaFeO3 powders were prepared using sol-gel method combined with microwave chemical synthesis. The powders were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM), respectively. The formaldehyde gas-sensing characteristics for the sample were examined. The experimental results indicate that the sensor based on the sample Zn-LaFeO3 shows excellent gas-sensing properties to formaldehyde gas. At the optimal operating temperature of 250°C, the sensitivity of the sensor based on LaFe0.7Zn0.3O3 to 100ppm formaldehyde is 38, while to other test gases, the sensitivity is all lower than 20. The response and recovery times for the sample to formaldehyde gas are 100s and 100s, respectively.

Synthesis and Gas Sensing Properties of SnO2 Nanostructures by Thermal Evaporation

2012 ◽  
Vol 620 ◽  
pp. 350-355 ◽  
Author(s):  
Wan Normiza Wan Mustapha ◽  
S.A. Rezan Sheikh Abdul Hamid ◽  
Sabar Derita Hutagalung ◽  
Nguyen Van Hieu ◽  
Khairudin Mohamed ◽  
...  
Keyword(s):  
Tin Oxide ◽  
Thermal Evaporation ◽  
Gas Sensing ◽  
Oxide Phase ◽  
Thermal Evaporation Method ◽  
X Ray ◽  
Sensing Properties ◽  
Synthesis Conditions ◽  
Gas Sensing Properties ◽  
Size And Morphology

Tin oxide nanostructures (NS) were grown on silicon substrates by thermal evaporation method with three different parameters. These parameters were temperatures (650 °C, 750 °C and 850 °C), nickel catalyst concentrations (0, 5 and 10 milimoles) and tin powder source to substrate distances (2 cm, 4 cm and 6 cm). The parameters were found to affect the size and morphology of the synthesized nanostructures. Formation of nanospheres (NSs), nanoneedles (NNs) and nanowires (NWs) of tin oxide were observed by Scanning Electron Microscope (SEM) at different synthesis conditions. Synthesis temperature was found to have most pronounced effect on the size and morphology of the nanostructures. Catalyst concentration has affected the porosity and growth of the nanostructures. The distance between source and substrate affected the nanostructures predominately on distribution and particle size. Energy dispersion X-ray (EDX) analysis confirms the presence of tin and oxygen in all nanostructures at all synthesis conditions. X-ray diffraction (XRD) proves the formation of tin oxide phase in all samples. Significant formation of tin oxide nanowires was observed at 850 °C. Gas sensing properties of SnO2 nanowires (NW) toward ethanol (C2H5OH) gas at 450°C with different volume concentration was measured. It was found SnO2 NW had good sensing properties for C2H5OH at 100 ppm compared to measurements made at 25-50 ppm.

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