scholarly journals Effect of Zn Doping in CuO Octahedral Crystals towards Structural, Optical, and Gas Sensing Properties

Crystals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 188 ◽  
Author(s):  
Chandra Prakash Goyal ◽  
Deepak Goyal ◽  
Sinjumol K. Rajan ◽  
Niranjan S. Ramgir ◽  
Yosuke Shimura ◽  
...  
Keyword(s):  
Work Function ◽  
Surface Defects ◽  
Gas Sensing ◽  
Oxygen Adsorption ◽  
Precipitation Method ◽  
Zn Doping ◽  
Sensor Resistance ◽  
Sensing Applications ◽  
Zinc Doping ◽  
Co Precipitation

Monodispersed CuO octahedral crystals were successfully synthesized using a low-temperature co-precipitation method. Zinc doping in CuO created surface defects that enhanced oxygen adsorption on the surface crucial for gas sensing applications. Pure and Zn-doped CuO sensor films were realized using the doctor blade method. The sensor films showed selective response towards a low concentration of NO2 at a lower operating temperature of 150 °C. Doping with Zn causes the resistance of the sensor film to decrease due to the enhancement of charge carriers with an analogous improvement in the sensor response. The observed decrease in sensor resistance agreed well with the findings of the work function studies. Zinc doping resulted in an increase in work function by 180 meV which, after NO2 exposure, was found to increase by a further 130 meV, attributed to the oxidizing behavior of the test gas.

Synthesis and characterization of ZnS-based quantum dots to trace low concentration of ammonia

2021 ◽  
Vol 42 (12) ◽  
pp. 122901
Author(s):  
Uma Devi Godavarti ◽  
P. Nagaraju ◽  
Vijayakumar Yelsani ◽  
Yamuna Pushukuri ◽  
P. S. Reddy ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Gas Sensing ◽  
High Sensitivity ◽  
Average Crystallite Size ◽  
Xrd Analysis ◽  
Precipitation Method ◽  
Zinc Blend ◽  
Ammonia Sensing ◽  
Sensing Applications ◽  
Co Precipitation

Abstract In the present work, a solution-based co-precipitation method has been adopted to synthesize pure and cobalt-doped ZnS quantum dots and characterized by XRD, SEM, TEM with EDX, FTIR and gas sensing properties. XRD analysis has shown a single phase of ZnS quantum dots having a zinc blend structure. TEM and XRD line broadening indicated that the average crystallite size in the sample is in the range of 2 to 5 nm. SEM micrographs show spherical-shaped quantum dots. FTIR studies show that cobalt has been successfully doped into the ZnS cubic lattice. EDX spectra have analyzed the elemental presence in the samples and it is evident that the spectra confirmed the presence of cobalt (Co), zinc (Zn), oxygen (O), and sulphur (S) elements only and no other impurities are observed. The ZnS-based quantum dot sensors reveal high sensitivity towards 50 ppm of ammonia vapors at an operating temperature of 70 °C. Hence, ZnS-based quantum dots can be a promising and quick traceable sensor towards ammonia sensing applications with good response and recovery time.

An Electrochemical Impedance Spectroscopy (EIS) Study of Zn-Doped Li (Ni1/3Co1/3Mn1/3) O2 Cathode Materials in the First Delithiation Process

2013 ◽  
Vol 833 ◽  
pp. 50-55 ◽  
Author(s):  
Lu Zheng ◽  
Liang Bin Liu ◽  
Xiao Jing Zhou ◽  
Yu Zhong Guo
Keyword(s):  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Cathode Materials ◽  
Electrochemical Impedance ◽  
Crystalline Lattice ◽  
Zn Doping ◽  
Voltage Range ◽  
Sei Film ◽  
Zinc Doping ◽  
Co Precipitation

Li (Ni1/3Co1/3Mn1/3) O2 cathode materials doped by Zn were synthesized by a co-precipitation routine, the first delithiation process of the samples with 0-4wt% of Zn doping were studied by electrochemical impedance spectroscopy (EIS) under the polarized voltage of 2.8-4.6V. The fitting results based on EIS data indicate that delithiation reactions happen within the voltage range of 3.7-4.4V ; The resistances of SEI film and charge transfer are both decreased significantly, whereas Li+ diffusion ability through layered crystalline lattice is improved largely with the increase of zinc doping from 0 to 4wt%.

scholarly journals Synthesis, characterization and DFT studies of zinc-doped copper oxide nanocrystals for gas sensing applications

2016 ◽  
Vol 4 (17) ◽  
pp. 6527-6539 ◽  
Author(s):  
V. Cretu ◽  
V. Postica ◽  
A. K. Mishra ◽  
M. Hoppe ◽  
I. Tiginyanu ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Dft Calculations ◽  
Copper Oxide ◽  
Fermi Level ◽  
Gas Sensing ◽  
Cost Effective ◽  
Dft Studies ◽  
Zn Doping ◽  
Sensing Applications ◽  
Effective Synthesis

A cost-effective synthesis was used to grow ZnxCu1−xOy nanostructures. DFT calculations show that charge transfer along with changes in Fermi level facilitate H2 gas sensing, which is further enhanced by Zn doping.

Gas sensing properties of magnesium ferrite prepared by co-precipitation method

2009 ◽  
Vol 488 (1) ◽  
pp. 270-272 ◽  
Author(s):  
P.P. Hankare ◽  
S.D. Jadhav ◽  
U.B. Sankpal ◽  
R.P. Patil ◽  
R. Sasikala ◽  
...  
Keyword(s):  
Gas Sensing ◽  
Precipitation Method ◽  
Magnesium Ferrite ◽  
Sensing Properties ◽  
Gas Sensing Properties ◽  
Co Precipitation

scholarly journals Evaluation of Indium Tin Oxide for Gas Sensing Applications: Adsorption/Desorption and Electrical Conductivity Studies on Powders and Thick Films

Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 497
Author(s):  
Stefan Dietrich ◽  
Mihails Kusnezoff ◽  
Uwe Petasch ◽  
Alexander Michaelis
Keyword(s):  
Electrical Conductivity ◽  
Carbon Monoxide ◽  
Tin Oxide ◽  
Indium Tin Oxide ◽  
Detrimental Effect ◽  
Gas Sensing ◽  
Oxygen Adsorption ◽  
Sensing Applications ◽  
Oxygen Coverage ◽  
Adsorption Desorption

By combining results of adsorption/desorption measurements on powders and electrical conductivity studies on thick and thin films, the interaction of indium tin oxide with various ambient gas species and carbon monoxide as potential target gas was studied between room temperature and 700 °C. The results show that the indium tin oxide surfaces exhibit a significant coverage of water-related and carbonaceous adsorbates even at temperatures as high as 600 °C. Specifically carbonaceous species, which are also produced under carbon monoxide exposure, show a detrimental effect on oxygen adsorption and may impair the film’s sensitivity to a variety of target gases if the material is used in gas sensing applications. Consequently, the operating temperature of an ITO based chemoresistive carbon monoxide sensor should be selected within a range where the decomposition and desorption of these species proceeds rapidly, while the surface oxygen coverage is still high enough to provide ample species for target gas interaction.

Influence of Doping on Structure and H2 Sensitivity of Nano-SnO2

2010 ◽  
Vol 96 ◽  
pp. 105-110 ◽  
Author(s):  
Hai Feng Liu ◽  
Tong Jiang Peng ◽  
Hong Juan Sun ◽  
Liang Fan ◽  
Boa Gang Guo
Keyword(s):  
Gas Sensing ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Gas Sensitivity ◽  
X Ray ◽  
Sensing Material ◽  
Crystal Properties ◽  
Co Precipitation ◽  
Special Environment ◽  
Semiconductor Properties

In order to improve the gas sensitivity of SnO2, Ni-doped and Co-doped nano-powders were prepared by the homogenous co-precipitation method using analytical pure SnCl4•5H2O and NH3•H2O as main materials under different doped ratios n (M2+)/n (Sn4+). The gas sensors were made by the thick film technique on mica substrates. The structure and crystal properties of the samples were investigated by X-ray diffraction (XRD). The results indicated that Sn4+ in the crystal lattice of SnO2 was partly replaced by M2+, which resulted in the change of the M-O bond lengths and the lattice parameters. The sensitivities of the sensors in H2 atmosphere with different concentrations at 75°C were tested. As a result, doped M2+ especially Ni2+ improves its H2 sensitivity, the sensitivities increases linearly with the increasing H2 concentration, and the best doping n(M2+)/n(Sn4+) of preparing gas-sensing material were obtained. The results show that doping which leads to the asymmetry of electrovalent balance of M-O octahedrons improves the activities and semiconductor properties of the powders. These studies play an important part in detecting reductive gases in special environment.

Nd 3+ Substituted Nanocrystalline Zinc Ferrite Sensors for Ethanol, LPG and Chlorine

2013 ◽  
Vol 310 ◽  
pp. 150-153 ◽  
Author(s):  
Pramod N. Vasambekar ◽  
Tukaram J. Shinde ◽  
Ashok B. Gadkari
Keyword(s):  
Zinc Ferrite ◽  
Gas Sensing ◽  
Operating Temperature ◽  
Maximum Sensitivity ◽  
Precipitation Method ◽  
Chemical Formula ◽  
Response Recovery ◽  
Gas Sensing Properties ◽  
Recovery Times ◽  
Co Precipitation

Nd 3+ substituted zinc ferrites with chemical formula ZnNdxFe 2-x O4 (x = 0, 0.01, 0.02, and 0.03) were prepared by oxalate co-precipitation method and characterized by XRD, IR and SEM techniques. The gas sensing properties were studied for ethanol, LPG and chlorine. It was observed that nanocrystalline ZnFe2O4 shows maximum sensitivity to ethanol (~41%) followed by LPG (~22%) and less sensitivity to Cl2 (~10%) at an operating temperature of 327oC. The sensitivity of zinc ferrites increases with increase in Nd 3+ content. Response-recovery times of zinc ferrite decreases with increase in Nd3+ content.

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