scholarly journals The Role of Different Lanthanoid and Transition Metals in Perovskite Gas Sensors

Sensors ◽  
2021 ◽  
Vol 21 (24) ◽  
pp. 8462
Author(s):  
Abdulaziz Alharbi ◽  
Benjamin Junker ◽  
Mohammad Alduraibi ◽  
Ahmad Algarni ◽  
Udo Weimar ◽  
...  
Keyword(s):  
Gas Sensors ◽  
Gas Sensing ◽  
Sol Gel ◽  
Surface Reactivity ◽  
Structured Materials ◽  
Gel Technique ◽  
Size And Morphology ◽  
Diffuse Reflectance Infrared ◽  
A Site

Beginning with LaFeO3, a prominent perovskite-structured material used in the field of gas sensing, various perovskite-structured materials were prepared using sol–gel technique. The composition was systematically modified by replacing La with Sm and Gd, or Fe with Cr, Mn, Co, and Ni. The materials synthesized are comparable in grain size and morphology. DC resistance measurements performed on gas sensors reveal Fe-based compounds solely demonstrated effective sensing performance of acetylene and ethylene. Operando diffuse reflectance infrared Fourier transform spectroscopy shows the sensing mechanism is dependent on semiconductor properties of such materials, and that surface reactivity plays a key role in the sensing response. The replacement of A-site with various lanthanoid elements conserves surface reactivity of AFeO3, while changes at the B-site of LaBO3 lead to alterations in sensor surface chemistry.

Insights into the role of strontium in toluene catalytic combustion over La1-xSrxCoO3 perovskites catalysts

2022 ◽  
Author(s):  
Mo Liu ◽  
Xiaoli Yang ◽  
ZiMeng Tian ◽  
Huimin Wang ◽  
Liangtao Yin ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Catalytic Combustion ◽  
Sol Gel ◽  
Gel Method ◽  
Sol Gel Method ◽  
A Site

A series of LaCoO3 pervoskite catalysts substituted by Sr in A site (La1-xSrxCoO3) were prepared via a facile sol-gel method. The catalytic activity of these pervoskite catalysts for the deep...

Modeling, Design, and Applications of the Gas Sensors Based on Graphene and Carbon Nanotubes

2017 ◽  
pp. 920-946
Author(s):  
Rafael Vargas-Bernal
Keyword(s):  
Carbon Nanotubes ◽  
Gas Sensors ◽  
Carbon Nanomaterials ◽  
Gas Sensing ◽  
Prospective Analysis ◽  
The Third ◽  
Potential Applications ◽  
Technical Advances ◽  
The Impact

Gas sensing continues attracting research communities due to its potential applications in the sectors military, industrial and commercial. A special emphasis is placed on the use of carbon nanomaterials such as carbon nanotubes and graphene, as sensing materials. The chapter will be divided as follows: In the first part, a description of the main topologies and materials (carbon nanomaterials plus polymers, metals, ceramics or combinations between these groups) used to fabricate gas sensors based on graphene and carbon nanotubes that are operated by conductance or resistance electrical, is realized. Next, different mathematical models that can be used to simulate gas sensors based on these materials are presented. In the third part, the impact of the graphene and carbon nanotubes on gas sensors is exemplified with technical advances achieved until now. Finally, it is provided a prospective analysis on the role of the gas sensors based on carbon nanomaterials in the next decades.

scholarly journals Discriminable Sensing Response Behavior to Homogeneous Gases Based on n-ZnO/p-NiO Composites

Nanomaterials ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 785 ◽  
Author(s):  
Wen-Dong Zhou ◽  
Davoud Dastan ◽  
Jing Li ◽  
Xi-Tao Yin ◽  
Qi Wang
Keyword(s):  
Gas Sensors ◽  
Gas Sensing ◽  
Sol Gel ◽  
High Sensitivity ◽  
Oxide Semiconductor ◽  
Sensing Properties ◽  
Gas Sensing Properties ◽  
P Type ◽  
Type Response ◽  
Properties Of Composites

Metal oxide semiconductor (MOS) gas sensors have the advantages of high sensitivity, short response-recovery time and long-term stability. However, the shortcoming of poor discriminability of homogeneous gases limits their applications in gas sensors. It is well-known that the MOS materials have similar gas sensing responses to homogeneous gases such as CO and H2, so it is difficult for these gas sensors to distinguish the two gases. In this paper, simple sol–gel method was employed to obtain the ZnO–xNiO composites. Gas sensing performance results illustrated that the gas sensing properties of composites with x > 0.425 showed a p-type response to both CO and H2, while the gas sensing properties of composites with x < 0.425 showed an n-type response to both CO and H2. However, it was interesting that ZnO–0.425NiO showed a p-type response to CO but an discriminable response (n-type) to H2, which indicated that modulating the p-type or n-type semiconductor concentration in p-n composites could be an effective method with which to improve the discriminability of this type of gas sensor regarding CO and H2. The phenomenon of the special gas sensing behavior of ZnO–0.425NiO was explained based on the experimental observations and a range of characterization techniques, including XRD, HRTEM and XPS, in detail.

Role of Catalyst on Refractive Index Tunability of Porous Silica Antireflective Coatings by Sol−Gel Technique

2007 ◽  
Vol 111 (23) ◽  
pp. 8291-8298 ◽  
Author(s):  
Abhilash Vincent ◽  
Suresh Babu ◽  
Erik Brinley ◽  
Ajay Karakoti ◽  
Sameer Deshpande ◽  
...  
Keyword(s):  
Refractive Index ◽  
Sol Gel ◽  
Porous Silica ◽  
Antireflective Coatings ◽  
Gel Technique

On the Role of Oxygen Vacancies in the Determination of the Gas-Sensing Properties of Tin-Oxide Nanowires

2006 ◽  
Vol 915 ◽  
Author(s):  
Roberto Mosca ◽  
Mingzheng Zha ◽  
Davide Calestani ◽  
Laura Lazzarini ◽  
Giancarlo Salviati ◽  
...  
Keyword(s):  
Gas Sensors ◽  
Oxygen Vacancies ◽  
Gas Sensing ◽  
Oxide Nanowires ◽  
Sensing Properties ◽  
Sno2 Nanowires ◽  
Gas Sensing Properties ◽  
First Results ◽  
Depth Study

AbstractSnO2 nanowires have been recently employed in the “gas-sensors” field and excellent results of conductometric and optical tests on SnO2 nanowires-based gas sensors have been reported.However, the mechanism that controls the gas-sensing effect in metal oxides nanowires is not fully understood yet. Here the authors present the first results of an in-depth study about the influence of post growth treatments on the physical and gas sensing properties of SnO2 nanowires.In particular, SnO2 nanowires grown by a vapour transport technique were annealed in a oxygen-rich atmosphere and then characterized by different techniques to assess the influence of the treatment on the nanowires properties.The annealing in oxygen atmosphere is shown to strongly affect the PL and CL spectra, the electrical resistivity as well as the gas sensing properties of the nanowires. The obtained results are consistent with a reduction of the oxygen vacancies concentration induced by the O2 treatment and seem to confirm the role of these defects in affecting the gas response of SnO2 nanowires-based sensors.

scholarly journals Role of Nanostructuring of Sensing Materials in Performance of Electrical Gas Sensors by Combining with Extra Strategies

Nano Express ◽  
2021 ◽  
Author(s):  
Bala Ismail Adamu ◽  
Peipei Chen ◽  
Weiguo Chu
Keyword(s):  
Gas Sensors ◽  
Performance Enhancement ◽  
Population Expansion ◽  
Light Sources ◽  
Three Dimension ◽  
Practical Applications ◽  
Fundamental Research ◽  
Rapid Industrialization ◽  
Size And Morphology

Abstract Nanostructuring, including tailoring dimensionality, size and morphology, and nanopatterning, is well recognized to play an increasingly important role in sensing units/chips of electrical gas sensors. As two predominant and fundamental configurations, chemiresistor- and field emission transistor (FET)-based electrical gas sensors are receiving increasing attention for fundamental research and practical applications. Herein, state-of-the-art overviews of electrical gas sensors are presented with emphasis on the role of nanostructuring in sensing units for both chemiresistors and FETs types, the strategies for their performance enhancement, and some key sensing mechanisms involved. Nanostructuring of sensing units and their dependence of the performance of chemiresistor- and FET-based gas sensors are discussed according to zero- (0D), one-(1D), two- (2D), and three-dimension (3D), respectively. Other types of gas sensors are also mentioned briefly. Some particular strategies such as loading external heat and light sources, electrical field, and mechanical forces for providing extra freedom to improve and optimize the performance are introduced in detail. Finally, a summary and future perspectives about gas sensors are given with some novel strategies, ideas, and solutions that could make it possible to meet the requirements of rapid industrialization, informatization, intelligentization, and population expansion.

Effect of A-site cationic radius on ceramic La0.67−xDyxSr0.33MnO3 prepared by sol–gel technique

2020 ◽  
Vol 31 (10) ◽  
pp. 7623-7629
Author(s):  
Fuxin Ling ◽  
Di Li ◽  
Ling Li ◽  
Hui Zhang ◽  
Ping Yu ◽  
...  
Keyword(s):  
Sol Gel ◽  
Gel Technique ◽  
Cationic Radius ◽  
A Site

scholarly journals Insight into Structural and Optical Properties of Pristine and Sr2+ Doped La2NiMnO6

2021 ◽  
Vol 58 (2) ◽  
pp. 59-71
Author(s):  
Javed Ahmad ◽  
Shoaib Hassan ◽  
Jamshaid Alam Khan ◽  
Umair Nissar ◽  
Hammad Abbas
Keyword(s):  
Sol Gel ◽  
Average Crystallite Size ◽  
Tangent Loss ◽  
Double Perovskites ◽  
Phonon Modes ◽  
Lorentz Oscillator ◽  
Reflectivity Spectra ◽  
Gel Technique ◽  
A Site ◽  
Insight Into

Double perovskites oxide (DPO) multiferroics La2-xSrxNiMnO6(x=0.0, 0.1, 0.2, 0.4, 0.6) are synthesized by sol-gel technique. The structural, optical and electrical (both DC and AC) properties of La2-xSrxNiMnO6 have been investigated by XRD and FTIR spectroscopy and two-probe resistivity and dielectric measurements as a function of temperature, respectively. The effect of doping of Strontium at A-site in double perovskites is discussed. XRD has revealed the formation of monoclinic structure of La2-xSrxNiMnO6 with space group P21 / n for x=0.0 and P21 for x=0.1, 0.2, 0.4, 0.6. The average crystallite size has been calculated to be in the range 31 to 46 nm as determined by Debye Scherrer equation. Infrared active optical phonons observed from reflectivity spectra have been analysed fitting the theoretical oscillators using Lorentz oscillator model. We have observed several well-resolved phonon modes in La2-xSrxNiMnO6 with increasing dopant concentration. Activation energy calculated using Arrhenius Plot is in the range of 0.31 to 0.18 eV, confirming the semiconducting nature of all samples. The dielectric constant and tangent loss as a function of temperature and frequency are also discussed for these multiferroics.

Photocatalytic degradation of indigo carmine by using tungsten doped bismuth vanadate

2021 ◽  
Vol 25 (7) ◽  
pp. 86-92
Author(s):  
Yasmin Ahmad ◽  
Suresh Ameta ◽  
Seema Kothari
Keyword(s):  
Photocatalytic Activity ◽  
Light Intensity ◽  
Photocatalytic Degradation ◽  
Sol Gel ◽  
Indigo Carmine ◽  
Bismuth Vanadate ◽  
Photogenerated Electrons ◽  
Gel Technique ◽  
Indigo Carmine Dye

The photocatalytic degradation of indigo carmine dye was studied using tungsten doped BiVO4. Bismuth vanadate powder has been synthesized by sol-gel technique. The incorporation of W ions into BiVO4 was confirmed by EDX. The photocatalytic activity was studied using different samples of BiVO4 by variation of pH, concentration of dye, dose of semiconductor and light intensity. It has been found that degradation of dye is more effective in presence of W doped BiVO4, It shows the role of tungsten ions for enhancing degradation of indigo carmine by reducing the recombination of photogenerated electrons and holes.

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