scholarly journals Effect of Pd and Au Sensitization of Bath Deposited Flowerlike TiO2Thin Films on CO Sensing and Photocatalytic Properties

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Ashok K. Singh ◽  
S. B. Patil ◽  
Umesh T. Nakate ◽  
K. V. Gurav
Keyword(s):  
Thin Films ◽  
Gas Sensing ◽  
Anatase Phase ◽  
Xrd Analysis ◽  
Gas Sensitivity ◽  
Recovery Times ◽  
Response And Recovery ◽  
Cbd Method ◽  
Effect Of Pd ◽  
Degradation Properties

TiO2thin films having flower structure with nanopetals are deposited by chemical bath deposition (CBD) method. Deposited TiO2films are formed in pure anatase phase as confirmed by X-ray diffraction (XRD) analysis. Deposited films are used for detection of environmental hazardous carbon monoxide (CO) gas and photocatalytic (PC) degradation of malachite green (MG) dye. Effect of Pd and Au catalysts sensitization on gas sensing as well as PC degradation properties is investigated. The use of catalyst led to enhancement in the gas sensitivity and reduction in the operating temperature as well as response and recovery times. The Au sensitized film showed better CO sensing performance and PC efficiency in comparison to unsensitized and Pd sensitized TiO2thin films. For Au sensitized film, gas sensitivity, response time, and recovery time are found to be 32% (14% for TiO2), 80 s, and 100 s, respectively, and PC efficiency is found to be 26.6% (16.9% for TiO2).

scholarly journals Gas-sensing features of nanostructured tellurium thin films

2020 ◽  
Vol 11 ◽  
pp. 1010-1018
Author(s):  
Dumitru Tsiulyanu
Keyword(s):  
Thin Films ◽  
Gas Sensing ◽  
Operating Temperature ◽  
Active Surface ◽  
Active Surface Area ◽  
Gas Sensitivity ◽  
Nanocrystalline And Amorphous ◽  
Recovery Times ◽  
Order Of Magnitude ◽  
Response And Recovery

Nanocrystalline and amorphous nanostructured tellurium (Te) thin films were grown and their gas-sensing properties were investigated at different operating temperatures with respect to scanning electron microscopy and X-ray diffraction analyses. It was shown that both types of films interacted with nitrogen dioxide, which resulted in a decrease of electrical conductivity. The gas sensitivity, as well as the response and recovery times, differed between these two nanostructured films. It is worth mentioning that these properties also depend on the operating temperature and the applied gas concentration on the films. An increase in the operating temperature decreased not only the response and recovery times but also the gas sensitivity of the nanocrystalline films. This shortcoming could be solved by using the amorphous nanostructured Te films which, even at 22 °C, exhibited higher gas sensitivity and shorter response and recovery times by more than one order of magnitude in comparison to the nanocrystalline Te films. These results were interpreted in terms of an increase in disorder (amorphization), leading to an increase in the surface chemical activity of chalcogenides, as well as an increase in the active surface area due to substrate porosity.

Gas Sensing Properties of Porous ZnO Nano-Platelet Films

2007 ◽  
Vol 1035 ◽  
Author(s):  
Amandeep Saluja ◽  
Jie Pan ◽  
Lei Kerr ◽  
Eunjung Cho ◽  
Seth Hubbard
Keyword(s):  
Gas Flow ◽  
Room Temperature ◽  
Gas Sensing ◽  
Electrode Spacing ◽  
Porous Films ◽  
Gas Sensitivity ◽  
Gas Sensing Properties ◽  
Recovery Times ◽  
Response And Recovery ◽  
Carrier Gas Flow

AbstractIn this work, various ZnO nanostructures were synthesized and a detailed study on the effect of different process parameters such as temperature, carrier gas flow, inter-electrode spacing, gas concentration and material properties on gas sensitivity was conducted. Initial ZnO nanoparticles were prepared by a simple solution chemical process and characterized by Secondary Electron Microscopy (SEM) and Brunauer, Emmet and Teller (BET) Sorptometer to demonstrate the morphology and surface area respectively. Sensitivity of nano-platelets and porous films was measured for different concentrations of the analytes (H2, CO). High response was observed at room temperature for H2 gas with sensitivities in excess 80% for 60ppm and about 55% for 80ppm of H2 gas at room temperature were observed for the nano-platelets and the porous films respectively with short response and recovery times of about 200 seconds. The sensitivity of the nano-platelets to CO gas was also measured and found to be about near 90% for 80 ppm CO at operating temperatures of 200 °C.

Mo-W-O thin films for CO sensing

2000 ◽  
Vol 638 ◽  
Author(s):  
Elisabetta Comini ◽  
Matteo Ferroni ◽  
Vincenzo Guidi ◽  
Giuliano Martinelli ◽  
Michele Sacerdoti ◽  
...  
Keyword(s):  
Thin Films ◽  
Gas Sensing ◽  
Weight Ratio ◽  
X Ray Diffraction ◽  
Composite Target ◽  
X Ray ◽  
Structural Characterisation ◽  
Gas Sensing Properties ◽  
Recovery Times ◽  
Response And Recovery

AbstractThe Mo-W-O thin films were deposited by RF reactive sputtering from composite target of W and Mo (20:80 weight ratio). Structural characterisation was carried out by X-ray diffraction spectroscopy and the composition of the film was obtained by Rutherford backscattering analysis. The layers were investigated by volt-amperometric technique for electrical and gas-sensing properties. The films were capable of sensing CO. No effect of poisoning of the surface was recorded and recovery of the resistance was complete. A concentration of CO as low as 15 ppm produced a relative variation in the conductance of 390% with response and recovery times of about 2 minutes at a working temperature of 200°C.

Au/Pd Bimetallic Nanoparticles Decorated SnSe2 Thin Films for NO2 Detection

2021 ◽  
Vol 21 (9) ◽  
pp. 4916-4920
Author(s):  
Sanju Rani ◽  
Manoj Kumar ◽  
Yogesh Singh ◽  
Vidya Nand Singh
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Ambient Temperature ◽  
Surface Area ◽  
Gas Sensing ◽  
Sensing Properties ◽  
Toxic Gases ◽  
Gas Sensing Properties ◽  
Recovery Times ◽  
Response And Recovery

In order to have a check and balance of the toxic gases in the environment, various kinds of sensors are currently being researched upon. As many of the toxic gases are also inflammable, therefore, there is a constant search for materials which can detect the gases at lower temperatures. Also, it is important that the sensor is selective for a particular gas. To meet such requirements, nanos-tructured materials are extensively being explored for such gas sensing applications, due to their large effective surface area. And, in order to further improve the gas sensing properties, metal catalysts are deposited over such nanomaterials. The smaller sized nanoparticles show better catalytic activity due to its effective larger surface area per unit volume. Depositing bimetallic materials is thus advantageous, since it can reduce the size of nanoparticles produced. In this work, ~7 nm thick Au/Pd thin film was sputter-coated over SnSe2 nanostructured thin films. SnSe2 thin film were deposited by thermally evaporating SnSe2 powder. The materials were characterized for their structural, morphological and gas sensing properties. The ambient temperature response for 5 parts per million (ppm) NO2 gas was measured to be 117%, with the response and recovery times being 10 and 19 seconds, respectively. The performance of the sensor improved with increase in the gas concentration and for 10 ppm gas, the recorded response was 137%, with the corresponding response and recovery times being 9 and 8 seconds, respectively. The limit of detection was 655 parts per billion (ppb). The mechanism of ambient temperature high response and low response/recovery times have been discussed based on physisorption, charge transfer, Au/Pd decoration and SnSe–SnSe2 based p–n junction. In addition, an important aspect of this work worth pointing out is the deposition of a thin film consisting of nanostructured network using an industrially viable thermal evaporation method. Thus, this work opens a new dimension for 2D materials that can be used for selective gas detection at ambient temperature.

scholarly journals Nanostructured CdO Thin Films for LPG and CO2 Gas Sensor Prepared by Spray Pyrolisis Technique

2014 ◽  
Vol 37 ◽  
pp. 31-46 ◽  
Author(s):  
R.H. Bari ◽  
S.B. Patil
Keyword(s):  
Thin Films ◽  
Deposition Time ◽  
Gas Sensing ◽  
Spray Deposition ◽  
Cadmium Acetate ◽  
Xrd Analysis ◽  
Glass Substrates ◽  
Response And Recovery ◽  
Cdo Thin Films ◽  
Gas Response

Nanostructured CdO thin films were deposited by spray pyrolysis techniques at different spray deposition time on glass substrates. Nanostructured CdO thin films was prepared using 0.05 M of cadmium acetate dehydrate (CH3COO) 2Cd·2H2O) was dissolved in the deionised water. These thin films were annealing in air at temperatures 500 °C for 60 min. The thickness of the films, crystallite and grain size were observed to increase with the increase in spray deposition time. As prepared thin films were characterized using XRD, FE-SEM and EDAX. The XRD analysis shows that CdO films were cubic structured. The electrical and gas sensing properties of these films were investigated. Prepared nanostructure CdO thin films show LPG (S = 1600) and CO2 (S = 435) gas response at different operating temperature. Gas response, selectivity, response and recovery time of the sensor were measured and presented.

Novel Preparation and Characterization of Fe2O3/CNT Thin Films for Flammable Gas Sensors

2019 ◽  
Vol 947 ◽  
pp. 47-51
Author(s):  
Buaworn Chaitongrat ◽  
Sutichai Chaisitsak
Keyword(s):  
Thin Films ◽  
Photoelectron Spectroscopy ◽  
Gas Sensing ◽  
Chemical Vapor ◽  
Dry Process ◽  
Vapor Deposition Technique ◽  
Flammable Gas ◽  
Recovery Times ◽  
Response And Recovery

In this work, novel preparation for Fe2O3/CNT thin films was investigated. The Fe/CNT thin films were synthesized through vertical floating-catalyst chemical vapor deposition technique (FC-CVD) and subsequently annealed in air. The various annealing temperature to create Fe2O3 was examined and characterized by field emission scanning electron microscopy (FE-SEM), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), Ultraviolet–visible spectroscopy (UV-Vis) and Raman spectroscopy. In addition, effect of wet/dry process on gas sensing of Fe2O3/CNTs was also investigated. The results suggest that the interfacial oxide layer helps to significantly improve LPG sensing performance with rapid response and recovery times. The proposed method can be considered as a promising approach for producing ultra-Fe2O3/CNT thin films that are appropriate for sensing application.

scholarly journals Ultrathin Leaf-Shaped CuO Nanosheets Based Sensor Device for Enhanced Hydrogen Sulfide Gas Sensing Application

Chemosensors ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 221
Author(s):  
Ahmad Umar ◽  
Hasan Algadi ◽  
Rajesh Kumar ◽  
Mohammad Shaheer Akhtar ◽  
Ahmed A. Ibrahim ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Gas Sensor ◽  
Gas Sensing ◽  
Average Crystallite Size ◽  
Xrd Analysis ◽  
Interplanar Distance ◽  
High Resolution Tem ◽  
Recovery Times ◽  
Response And Recovery ◽  
Cuo Nanosheets

Herein, a simple, economical and low temperature synthesis of leaf-shaped CuO nanosheets is reported. As-synthesized CuO was examined through different techniques including field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), X-ray diffraction (XRD), fourier transform infrared spectroscopic (FTIR) and Raman spectroscopy to ascertain the purity, crystal phase, morphology, vibrational, optical and diffraction features. FESEM and TEM images revealed a thin leaf-like morphology for CuO nanosheets. An interplanar distance of ~0.25 nm corresponding to the (110) diffraction plane of the monoclinic phase of the CuO was revealed from the HRTEM images XRD analysis indicated a monoclinic tenorite crystalline phase of the synthesized CuO nanosheets. The average crystallite size for leaf-shaped CuO nanosheets was found to be 14.28 nm. Furthermore, a chemo-resistive-type gas sensor based on leaf-shaped CuO nanosheets was fabricated to effectively and selectively detect H2S gas. The fabricated sensor showed maximum gas response at an optimized temperature of 300 °C towards 200 ppm H2S gas. The corresponding response and recovery times were 97 s and 100 s, respectively. The leaf-shaped CuO nanosheets-based gas sensor also exhibited excellent selectivity towards H2S gas as compared to other analyte gases including NH3, CH3OH, CH3CH2OH, CO and H2. Finally, we have proposed a gas sensing mechanism based upon the formation of chemo-resistive CuO nanosheets.

Deposition time dependent study of structural and optical properties of PbS thin films grown by CBD method

2020 ◽  
Vol 13 ◽  
Author(s):  
Minakshi Chaudhary ◽  
Yogesh Hase ◽  
Ashwini Punde ◽  
Pratibha Shinde ◽  
Ashish Waghmare ◽  
...  
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Band Gap ◽  
Deposition Time ◽  
Secondary Growth ◽  
Cost Effective ◽  
Xrd Analysis ◽  
Structural Morphology ◽  
Glass Substrates ◽  
Cbd Method

: Thin films of PbS were prepared onto glass substrates by using a simple and cost effective CBD method. Influence of deposition time on structural, morphology and optical properties have been investigated systematically. The XRD analysis revealed that PbS films are polycrystalline with preferred orientation in (200) direction. Enhancement in crystallinity and PbS crystallite size has been observed with increase in deposition time. Formation of single phase PbS thin films has been further confirmed by Raman spectroscopy. The surface morphology analysis revealed the formation of prismatic and pebble-like PbS particles and with increase in deposition time these PbS particles are separated from each other without secondary growth. The data obtained from the EDX spectra shows the formation of high-quality but slightly sulfur rich PbS thin films over the entire range of deposition time studied. All films show increase in absorption with increase in deposition time and a strong absorption in the visible and sub-band gap regime of NIR range of the spectrum with red shift in band edge. The optical band gap shows decreasing trend, as deposition time increases but it is higher than the band gap of bulk PbS.

A facile method for preparation of porous nitrogen-doped Ti Ti3C2Tx MXene for highly responsive acetone detection at high temperature

2021 ◽  
pp. 2151043
Author(s):  
Zijing Wang ◽  
Fen Wang ◽  
Angga Hermawan ◽  
Jianfeng Zhu ◽  
Shu Yin
Keyword(s):  
Gas Sensor ◽  
Recovery Time ◽  
Gas Sensing ◽  
Three Dimensional ◽  
Gas Sensitivity ◽  
Nitrogen Doped ◽  
Dimensional Network ◽  
Potential Applications ◽  
Response And Recovery ◽  
Acetone Detection

Porous nitrogen-doped Ti3C2T[Formula: see text] MXene (N-TCT) with a three-dimensional network structure is synthesized via a simple sacrifice template method and then utilized as an acetone gas sensor. By introducing nitrogen atoms as heteroatoms into Ti3C2T[Formula: see text] nanosheets, some defects generate around the doped nitrogen atoms, which can greatly improve the surface hydrophilicity and adsorption capacity of Ti3C2T[Formula: see text] Mxene nanosheets. It resulted in the enhanced gas sensitivity, achieving a response value of about 36 ([Formula: see text]/[Formula: see text] × 100%) and excellent recovery time (9s) at 150[Formula: see text]C. Compared with the pure Ti3C2T[Formula: see text]-based gas sensor (381/92s), the response and recovery time are both obviously improved, and the response value increased by 3.5 times. The gas-sensing mechanism of the porous N-TCT is also discussed in detail. Based on the excellent gas sensitivity of porous N-TCT for highly responsive acetone detection at high temperatures, the strategy of nitrogen-doped two-dimensional nanomaterials can be extended to other nanomaterials to realize their potential applications.

scholarly journals Chemically synthesized PbS Nano particulate thin films for a rapid NO2 gas sensor

2016 ◽  
Vol 34 (1) ◽  
pp. 204-211 ◽  
Author(s):  
Vishal V. Burungale ◽  
Rupesh S. Devan ◽  
Sachin A. Pawar ◽  
Namdev S. Harale ◽  
Vithoba L. Patil ◽  
...  
Keyword(s):  
Thin Films ◽  
Gas Sensor ◽  
Gas Sensing ◽  
Operating Temperature ◽  
Morphological Properties ◽  
X Ray Diffraction ◽  
Gas Sensitivity ◽  
Silar Method ◽  
Layer Adsorption ◽  
Gas Sensing Properties

AbstractRapid NO2 gas sensor has been developed based on PbS nanoparticulate thin films synthesized by Successive Ionic Layer Adsorption and Reaction (SILAR) method at different precursor concentrations. The structural and morphological properties were investigated by means of X-ray diffraction and field emission scanning electron microscope. NO2 gas sensing properties of PbS thin films deposited at different concentrations were tested. PbS film with 0.25 M precursor concentration showed the highest sensitivity. In order to optimize the operating temperature, the sensitivity of the sensor to 50 ppm NO2 gas was measured at different operating temperatures, from 50 to 200 °C. The gas sensitivity increased with an increase in operating temperature and achieved the maximum value at 150 °C, followed by a decrease in sensitivity with further increase of the operating temperature. The sensitivity was about 35 % for 50 ppm NO2 at 150 °C with rapid response time of 6 s. T90 and T10 recovery time was 97 s at this gas concentration.

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