LPG and NH3 sensing characteristics of DC electrochemically deposited Co3O4 films

Present communication reports the LPG and NH 3 sensing properties of Co 3 O 4 films prepared on throughly cleaned stainless steel (SS) and copper ( CU ) substrates by using DC electrochemical deposition method followed by air annealing at 350°C/2 h. The resultant films are characterized by using X-ray diffraction (XRD), Raman spectroscopy and scanning electron microscopy (SEM). The LPG and NH 3 gas sensing properties of these films are measured at room temperature (RT) by using static gas sensing system at different concentrations of test gas ranging from ~ 25 ppm to 350 ppm. The XRD and Raman spectroscopy studies clearly indicated the formation of pure cubic spinel Co 3 O 4 in all films. The LPG and NH 3 gas sensing properties of films showed (i) the increase in sensitivity factor (S.F.) with gas concentrations and (ii) more sensibility to LPG as compared to NH 3 gas. In case of NH 3 gas (conc. ~ 150 ppm) and LPG gas (conc. ~ 60 ppm) sensing, the maximum S.F. = 270 and 258 are found for the films deposited on CU substrates, respectively. For all films, the response time (3–5 min.) is found to be much higher than the recovery time (30–50 sec). For all films, the response and recovery time are found to be higher for LPG as compared to NH 3 gas. Further, repeatability–reproducibility in gas sensing properties is clearly noted by analysis of data for number of cycles recorded for all films from different set of depositions.

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Influence of Al Doping on the Morphological, Structural and Gas Sensing Properties of Electrochemically Deposited ZnO Films on Quartz Resonators

Coatings ◽

10.3390/coatings12010081 ◽

2022 ◽

Vol 12 (1) ◽

pp. 81

Author(s):

Gergana Alexieva ◽

Konstantin Lovchinov ◽

Miroslav Petrov ◽

Rositsa Gergova ◽

Nikolay Tyutyundzhiev

Keyword(s):

Gas Sensing ◽

Zno Films ◽

Active Surface Area ◽

Average Roughness ◽

Sensing Properties ◽

Developed Surface ◽

Gas Sensing Properties ◽

Electrochemically Deposited ◽

Doped Zno ◽

Quartz Resonators

The detection of hazardous gases at different concentration levels at low and room temperature is still an actual and challenging task. In this paper, Al-doped ZnO thin films are synthesized by the electrochemical deposition method on the gold electrodes of AT-cut quartz resonators, vibrating at 10 MHz. The average roughness, surface morphology and gas sensing properties are investigated. The average roughness of Al-doped ZnO layers strongly depends on the amount of the doping agent Al2(SO4)3 added to the solution. The structural dependence of these films with varying Al concentrations is evident from the scanning electron microscopy images. The sensing properties to ethanol and ammonia analytes were tested in the range of 0–12,800 ppm. In the analysis of the sensitivity to ammonia, a dependence on the concentration of the added Al2(SO4)3 in the electrochemically deposited layers is also observed, as the most sensitive layer is at 3 × 10−5 M. The sensitivity and the detection limit in case of ammonia are, respectively, 0.03 Hz/ppm and 100 ppm for the optimal doping concentration. The sensitivity depends on the active surface area of the layers, with those with a more developed surface being more sensitive. Al-doped ZnO layers showed a good long-term stability and reproducibility towards ammonia and ethanol gases. In the case of ethanol, the sensitivity is an order lower than that for ammonia, as those deposited with Al2(SO4)3 do not practically react to ethanol.

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Au-sensitized WO3 nanoparticles synthesized and their enhanced acetone sensing properties

Functional Materials Letters ◽

10.1142/s1793604718500716 ◽

2018 ◽

Vol 11 (04) ◽

pp. 1850071 ◽

Cited By ~ 5

Author(s):

Dongping Xue ◽

Zhanying Zhang

Keyword(s):

Recovery Time ◽

Gas Sensing ◽

Test Results ◽

X Ray Diffraction ◽

X Ray ◽

Sensing Properties ◽

Response Recovery ◽

Two Samples ◽

Gas Sensing Properties ◽

Scanning Electron

Au-sensitized WO3 nanoparticles have been synthesized by a facile two-step hydrothermal method. The structures, morphologies and surface compositions of the materials were characterized by X-ray diffraction (XRD), energy dispersive spectroscopy (EDS) and scanning electron microscopy (SEM). The test results show that we have prepared higher purity Au-sensitized WO3 nanoparticles. The gas-sensing properties of pure and Au-sensitized WO3 nanoparticles on acetone vapor were further investigated. The results obtained show that the response-recovery time of the two samples prepared is relatively short compared to that reported in the current literature. The Au-sensitized WO3 nanoparticles are significantly more sensitive and selective than the pure WO3 nanoparticles. This may be mainly attributed to the synergy between Au and WO3. It is expected that the Au-sensitized WO3 nanoparticles thus prepared can also be used for research in other fields.

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Gas Response for Ethanol of SnO2 Nanorods as Sensing Materials

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.399-401.727 ◽

2011 ◽

Vol 399-401 ◽

pp. 727-730

Author(s):

Yue Huan Li ◽

Yong Jun Liu ◽

Xue Chun Xiao ◽

Hu En Kan ◽

He Yun Zhao

Keyword(s):

Solid State ◽

Response Time ◽

Solid State Reaction ◽

Recovery Time ◽

Gas Sensing ◽

Rutile Structure ◽

Sensing Properties ◽

Gas Sensing Properties ◽

Gas Response ◽

Indirect Heating

SnO2nanorods with rutile structure were successfully synthesized by solid state reaction in the presence of NaCl-KCl. Indirect-heating sensors based on nanorods were fabricated and investigated for the gas sensing properties to ethanol. The results showed that the response of sensor to 1000 ppm ethanol is up to 114.3, the export voltage to 1 ppm ethanol can attain 2.0 V at 275 °C, and the response time and recovery time are no longer than 10 s.

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