Switchable p-n gas response for 3D-hierarchical NiFe2O4 porous microspheres for highly selective and sensitive toluene gas sensors

2021 ◽  
pp. 161281
Author(s):  
K. Karuppasamy ◽  
Bharat Sharma ◽  
Dhanasekaran Vikraman ◽  
Eun-Bee Jo ◽  
P. Sivakumar ◽  
...  
Keyword(s):  
Gas Sensors ◽  
Porous Microspheres ◽  
Gas Response

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.

Gas response times of nano-scale SnO2 gas sensors as determined by the moving gas outlet technique

2007 ◽  
Vol 126 (1) ◽  
pp. 174-180 ◽  
Author(s):  
A HELWIG ◽  
G MULLER ◽  
G SBERVEGLIERI ◽  
G FAGLIA
Keyword(s):  
Gas Sensors ◽  
Response Times ◽  
Nano Scale ◽  
Gas Response

scholarly journals Semiconducting ZnO Nanofibers as Gas Sensors and Gas Response Improvement by SnO<sub>2</sub> Coating

ETRI Journal ◽  
2009 ◽  
Vol 31 (6) ◽  
pp. 636-641 ◽  
Author(s):  
Jaehyun Moon ◽  
Jin-Ah Park ◽  
Su-Jae Lee ◽  
Taehyoung Zyung
Keyword(s):  
Gas Sensors ◽  
Zno Nanofibers ◽  
Gas Response

Effect of Au Doped WO3 Gas Sensors for NO2 Detection

2011 ◽  
Vol 492 ◽  
pp. 308-311 ◽  
Author(s):  
Wu Bin Gao ◽  
Cheng Dong ◽  
Xu Liu ◽  
Yun Han Ling ◽  
Jia Lin Sun
Keyword(s):  
Gas Sensors ◽  
Gas Sensing ◽  
Point Contact ◽  
X Ray ◽  
Sensing Properties ◽  
Gas Sensing Properties ◽  
Tungsten Filaments ◽  
Gas Response ◽  
Contact Sensors

Gas sensor based on point contact tungsten trioxide (WO3) was prepared by in-situ induction-heating thermal oxidation of tungsten filaments. X-ray diffractometry (XRD) and field emission scanning electron microscopy (FESEM) were employed to analyze the phase and the morphology of the fabricated thin films. The results showed that the WO3films exhibited a monoclinic phase and were composed of hierarchical micro and nano crystals. The NO2(1-8 ppm) sensing properties of the point contact sensors based on Pure and Au-sputtering doped (2.5 at%) WO3films were investigated. The results showed that the gas sensing properties of the Au (2.5 at%) doped WO3sensors were superior to those of the undoped. The obtained point contact WO3sensor exhibited the maximum NO2gas response at 100°C.

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.

Using of SILD technology for surface modification of SnO2 films for gas sensor applications

2002 ◽  
Vol 750 ◽  
Author(s):  
G. Korotcenkov ◽  
V. Macsanov ◽  
Y. Boris ◽  
V. Brinzari ◽  
V. Tolstoy ◽  
...  
Keyword(s):  
Surface Modification ◽  
Gas Sensor ◽  
Gas Sensors ◽  
Sensor Applications ◽  
Layer Deposition ◽  
Ag Clusters ◽  
Ag Deposition ◽  
Gas Response ◽  
Ionic Layer ◽  
Deposition Technology

ABSTRACTThe possibilities of SILD (successive ionic layer deposition) technology for modification of surface properties of nano-scaled SnO2 films for gas sensor applications were studied and are discussed in this article. Samples of SnO2 with thickness ranging from 30–40 nm were deposited by spray pyrolysis from SnCl4-water solutions. Nano-clusters of Pd and Ag, deposited by the SILD method were applied for surface modification. PdCl2 and AgNO3 were used as precursors for Pd and Ag deposition on the SnO2 surface.It was found that the method of surface modification by SILD can be used for improving both the sensitivity and the rate of gas response of SnO2-based gas sensors to CO and H2. At the same time, the presence of Pd and Ag clusters on the surface of SnO2 depresses the gas response to ozone.

scholarly journals ppb-Level Selective Hydrogen Gas Detection of Pd-Functionalized In2O3-Loaded ZnO Nanofiber Gas Sensors

Sensors ◽  
2019 ◽  
Vol 19 (19) ◽  
pp. 4276 ◽  
Author(s):  
Jae-Hyoung Lee ◽  
Jae-Hun Kim ◽  
Jin-Young Kim ◽  
Ali Mirzaei ◽  
Hyoun Woo Kim ◽  
...  
Keyword(s):  
Gas Sensors ◽  
Gas Sensing ◽  
Hydrogen Gas ◽  
Strong Response ◽  
Pd Nanoparticle ◽  
Highly Sensitive ◽  
Hydrogen Gas Sensors ◽  
Zno Nanofibers ◽  
Gas Response ◽  
Hydrogen Gas Detection

Pd nanoparticle-functionalized, xIn2O3 (x = 0.05, 0.1, and 0.15)-loaded ZnO nanofibers were synthesized by an electrospinning and ultraviolet (UV) irradiation method and assessed for their hydrogen gas sensing properties. Morphological and chemical analyses revealed the desired morphology and chemical composition of the synthesized nanofibers. The optimal gas sensor namely Pd-functionalized, 0.1In2O3-loaded ZnO nanofibers showed a very strong response to 172–50 ppb hydrogen gas at 350 °C, which is regarded as the optimal sensing temperature. Furthermore, the gas sensors showed excellent selectivity to hydrogen gas due to the much lower response to CO and NO2 gases. The enhanced gas response was attributed to the excellent catalytic activity of Pd to hydrogen gas, and the formation of Pd/ZnO and In2O3/ZnO heterojunctions, ZnO–ZnO homojunction, as well as the formation of PdHx. Overall, highly sensitive and selective hydrogen gas sensors can be produced based on a simple methodology using a synergistic effect from Pd functionalization and In2O3 loading in ZnO nanofibers.

Gas Response Properties of Noble Metal Modified TiO2 Gas Sensor

2013 ◽  
Vol 706-708 ◽  
pp. 126-129
Author(s):  
Mao Lin Zhang ◽  
Tao Ning ◽  
Yu Hong Yang
Keyword(s):  
Activation Energy ◽  
Noble Metal ◽  
Gas Sensors ◽  
Response Mechanism ◽  
X Ray Diffraction ◽  
Response Properties ◽  
X Ray ◽  
Response Characteristics ◽  
Gas Response ◽  
Scanning Electron

The response characteristics of noble metal (platinum and palladium) modified TiO2 gas sensors were investigated, respectively. X-ray diffraction (XRD) and scanning electron microscope (SEM) were used to characterize the sensing films. In addition, the resistance of sensors response to oxygen partial pressure was discussed by Kroger–Vink model. The response properties indicated that Pt modified TiO2 was providing excellent response properties when the sensor exposed to hydrogen and oxygen. The response mechanism was suggested to arise from the activation energy (E) of the modified sensing films.

scholarly journals On the Low-Temperature Response of Semiconductor Gas Sensors

2009 ◽  
Vol 2009 ◽  
pp. 1-17 ◽  
Author(s):  
A. Helwig ◽  
G. Müller ◽  
G. Sberveglieri ◽  
M. Eickhoff
Keyword(s):  
Low Temperature ◽  
Amorphous Silicon ◽  
Gas Sensors ◽  
Hydrogenated Amorphous Silicon ◽  
Lone Pair ◽  
Temperature Response ◽  
Adsorbed Water ◽  
Semiconductor Materials ◽  
Gas Response ◽  
Hydrogenated Amorphous

The present paper compares three different kinds of semiconductor gas sensing materials: metal oxides (MOX), hydrogen-terminated diamond (HD), and hydrogenated amorphous silicon (a-Si:H). Whereas in MOX materials oxygen is the chemically reactive surface species, HD and a-Si:H are covalently bonded semiconductors with hydrogenterminated surfaces. We demonstrate that these dissimilar semiconductor materials exhibit the same kind of low-temperature gas response. This low-temperature response-mechanism is mediated by a thin layer of adsorbed water with the semiconductor materials themselves acting as pH sensors. In this adsorbate-limited state the gas sensitivity is limited to molecular species that can easily dissolve in and subsequently undergo electrolytic dissociation. At higher temperatures, where a closed layer of adsorbed water can no longer exist, the gas response is limited by direct molecule-semiconductor interactions. In this latter mode of operation, MOX gas sensors respond to adsorbed gases according to their different oxidising or reducing properties. Hydrogenated amorphous silicon (a-Si:H), on the other hand, exhibits a significantly different cross sensitivity profile, revealing that gas-surface interactions may largely be restricted to analyte molecules with lone-pair and electron-deficient three-centre orbitals.

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