Structure and CO Gas Sensing Properties of PPy/LaFeO3 Nanocomposites

2011 ◽  
Vol 675-677 ◽  
pp. 375-378
Author(s):  
Peng Song ◽  
Qi Wang

In this paper, perovskite LaFeO3 nanoparticles were synthesised by a sol-gel method. Then, polypyrrole (PPy)/LaFeO3 nanocomposites were prepared by a simple in situ chemical polymerization method. By means of X-ray diffraction (XRD), Fourier transform infrared (FTIR) and scanning electron microscopy (SEM), the microstructure of PPy/LaFeO3 nanocomposites was characterized. The XRD patterns indicated that LaFeO3 nanoparticles have a perovskite phase with orthorhombic structure, and incorporation of PPy did not change the crystalline structure of LaFeO3. The PPy was evenly dispersed on the surface of LaFeO3 particles, which was endorsed by FTIR spectral analyses. And SEM images indicate that the PPy was evenly dispersed on the surface of LaFeO3 particles without apparent agglomeration. And we found that the nanocomposites exhibited a higher response to CO gas.

2017 ◽  
Vol 727 ◽  
pp. 327-334
Author(s):  
Yan Wang ◽  
Jun Wang ◽  
Xiao Fei Zhang ◽  
Ya Qing Liu

La-Nd co-doped barium hexaferrites, Ba0.7(LamNdn)0.3Fe12O19 (D-BaM), were successfully prepared by sol-gel method. PANI / D-BaM composites were synthesized by in-situ polymerization in solution. The structure, morphology and properties of samples have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), vibrating sample magnetometer (VSM), four-probe conductivity tester and vector network analyzer. The XRD patterns showed that the crystal structure of all the samples exist as M-type phases. The SEM images revealed that the particles presented a hexagonal platelet-like morphology. The magnetic properties could be improved by substitutions of La and Nd ions. The saturation magnetization (Ms) and coercive force (Hc) increased with the change of La / Nd ratio to the maximum at La / Nd = 3:1. The doped particles have also been embedded in conductive PANI to prepare electromagnetic materials, and the conductivity kept on the order of 10-2. The microwave absorbing properties of composites at 30 MHz-6 GHz improved obviously, the peak value of reflection loss could reach-7.5 dB.


2021 ◽  
Vol 12 (4) ◽  
pp. 2523-2529
Author(s):  
Daniel Sam N ◽  
Anish C I ◽  
Sabeena G ◽  
Rajaduraipandian S ◽  
Manobala ◽  
...  

Sol gel methods were used for the study of the antimicrobial activity of Cd-TiO2 against gram-negative and positive bacteria. These Cd-TiO2 have been characterized by various optical and techniques. They have been exhibited by X-ray diffraction, scanning electron microscopy, ultraviolet spectroscopy, and infrared spectroscopy. The structures of the various XRD patterns indicate that the product has a structure. The particle size of Cd-TiO2 is 35nm. The SEM images confirm the spherical appearance of the sample. The energy X-ray spectra have been confirmed as well and then C, O, Ti, Cd, Pt element are present in Cd-TiO2. The weight percentage of Cadmium is 5.8%, Ti is 51.03%, C is 5.13% and O is 31.75% in Cd-TiO2. BET image shows that the major pore size distribution of Cd-TiO2 is ranged from 2.24 nm. The Cd-TiO2 that the antibacterial activity when tested against the pathogens only gram-negative bacteria such as Pseudomonas. The zone of minimum inhibition concentration was measured in a range of 20mm in 25μl and 30mm in 100μl.


2016 ◽  
Vol 697 ◽  
pp. 293-296
Author(s):  
Xiao Yang Zhang ◽  
Xi Wei Qi ◽  
Zhi Yuan Yang ◽  
Li Bao ◽  
Min Zhang

Hydrothermal method and sol-gel process were used to synthesize multiferroic BiFeO3 ceramics. X-ray diffraction, scanning electron microscopy, vickers diamond indenter and three-point bending method were used to investigate the effects of methods on the phase structure, microstructures and mechanical properties. Cold isostatic pressing on the ceramics with two different loads (10 MPa, 200 MPa) was used to illustrate the influence of pressure in mechanical properties. The results show that all samples are crystallized in the perovskite phase. A few small traces of impurity are observed at a 2θ of ~28 o, which are found to be those of Bi2Fe4O9. The SEM images depict that samples prepared by sol-gel process are more uniform and the grain size is slightly larger than that of hydrothermal processed samples. The investigations on the hardness and flexural strength demonstrate the ceramics prepared by hydrothermal method have better mechanical properties than that of sol-gel process, and the mechanical properties can be obviously enhanced by increasing pressure.


Author(s):  
Hemalatha Parangusan ◽  
Jolly Bhadra ◽  
Zubair Ahmad ◽  
Shoaib Mallick ◽  
Farid Touati ◽  
...  

In this letter, we report the structural, morphological and CO2 gas sensing properties of the polyaniline (PANI) coated Cu-ZnS microspheres. PANI coated Cu-ZnS microspheres were prepared by hydrothermal and in-situ polymerization method. X-ray diffraction, Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and transmission electron microscope (TEM) were used to investigate the structural and morphological properties. The fabricated sensor based on PANI coated Cu-ZnS microspheres exhibits good CO2 sensing performance with rapid response (31 s) and recovery (23 s) times.


2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Beyene Tesfaw Ayalew ◽  
P. Vijay Bhaskar Rao

Ce0.5Sr0.5 (Co0.8Fe0.2)1−x ZrxO3−δ (CSCFZ) powders were synthesized by the sol-gel method and characterized to study structural and electrochemical properties. X-ray diffractometer (XRD) patterns of all samples give nanosized particles of a high-degree crystalline cathode having a cubic-type perovskite structure of space group Pm-3m with the existence of oxygen vacancies in the lattices. The results have the perovskite phase with average crystallite sizes of 26.57 nm, 18.14 nm, 18.13 nm, and 18.12 nm with porosities of 9.93%, 9.87%, 9.50%, and 9.08% for x = 0, 0.1, 0.15, and 0.2, respectively. Scanning electron microscope (SEM) micrographs showed the presence of pores on the microstructure. Average grain sizes of prepared samples found from SEM images were in the range of 105.30–183.02 nm. The partial substitution of zirconium at the B-site shows more stable materials than the host without decreasing the porosity that much. The results of electronic conductivity analyzed by the four-probe dc technique show that the conductivity of synthesized materials increases with the increment of both dopant concentration and temperature by the decrement of area specific resistances. The electrical conductivity of CSCFZ steadily increased with the increment of temperature which reached 42.76 Scm−1 at around 450°C.


2018 ◽  
Vol 5 (10) ◽  
pp. 171691 ◽  
Author(s):  
Rui Lu ◽  
Xiaoling Zhong ◽  
Shiguang Shang ◽  
Shan Wang ◽  
Manling Tang

Pure WO 3 and Ag-WO 3 (mixed solid solutions Ag with WO 3 ) have been successfully synthesized by sol-gel method and the influences of calcination temperature on the particle size, morphology of the WO 3 and Ag-WO 3 nanoparticles were investigated. Powder X-ray diffraction results show that the hexagonal to monoclinic phase transition occurs at calcination temperature varying from 300°C to 500°C. SEM images show that calcination temperature plays an important role in controlling the particle size and morphology of the as-prepared WO 3 and Ag-WO 3 nanoparticles. The NO 2 gas sensing properties of the sensors based on WO 3 and Ag-WO 3 nanoparticles calcined at different temperatures were investigated and the experimental results exhibit that the gas sensing properties of the Ag-WO 3 sensors were superior to those of the pure WO 3 . Especially, the sensor based on Ag-WO 3 calcined at 500°C possessed larger response, better selectivity, faster response/recovery and better longer-term stability to NO 2 than the others at relatively low operating temperature (150°C).


2013 ◽  
Vol 575-576 ◽  
pp. 20-23 ◽  
Author(s):  
Yu Zhen Ma ◽  
Peng Song ◽  
Qi Wang

Biomorphic porous LaFeO3 samples were prepared using aspen leaves as biotemplates. The structural and microscopy characterization has been carried out with X-ray diffraction, scanning electron microscopy and transmission electron microscopy. XRD patterns confirm thatLaFeO3 shows perovskite phase with orthorhombic structure. The results of SEM and TEM revealed that the the obtained LaFeO3 with hollow and porous structure. And the porous LaFeO3 is composed of spherical particles with the size of 50-80 nm The gas sensing performance of as-prepared LaFeO3 nanocrystlas was investigated. It is found that porous LaFeO3 calcined at 700°C exhibit good sensitivity to acetone with rapid response.


2015 ◽  
Vol 5 (1) ◽  
pp. 46
Author(s):  
Novesar Jamarun ◽  
Lia Anggresani ◽  
Syukri Arief

 ABSTRACT Preparation of Dip-Coating Calcium Phosphate via sol-gel method using natural limestone Bukit Tui as calcium precursors and diammonium hydrogen phosphate as phosphorus precursors with sol-gel process has been investigated. Ethanol was used as solvent and DEA (diethanolamine) was used stabilizing agent. The powder were prepared by calcinated the sol at 950 oC. The products were characterized by Fourier Transform Infra Red, X-Ray Diffraction and Scanning Electron Microscopy. FTIR results showed that the vibration form was PO43-, P2O74-, O-H and CO2. XRD patterns of powder with various Ca/P mol ratio showed that the product of calcium phosphate was Ca2P2O7 and also found the hydroxyapatite Ca10(PO4)6(OH)2 in Ca/P mol ratio 1,7. SEM images of powder calcium phosphate revealed that their morphology were spheric and homogen. The coating process was done at glass substrate with coating speed 20 cm/min by calcinations at 400 oC. XRD patterns of thin layer showed that the product was Ca2P2O7 and SEM images of thin layer revealed that their morphology were bulk. Keywords: Natural limestone, calcium phosphate, hydroxyapatite, sol-gel, dip-coating


2004 ◽  
Vol 79 (4-6) ◽  
pp. 1303-1305 ◽  
Author(s):  
L. Zbroniec ◽  
A. Martucci ◽  
T. Sasaki ◽  
N. Koshizaki

2015 ◽  
Vol 29 (01) ◽  
pp. 1450254 ◽  
Author(s):  
M. Shayani Rad ◽  
A. Kompany ◽  
A. Khorsand Zak ◽  
M. E. Abrishami

Pure and silver added zinc oxide nanoparticles ( ZnO -NPs and ZnO : Ag -NPs) were synthesized through a modified sol–gel method. The prepared samples were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM) and photoluminescence (PL) spectroscopy. In the XRD patterns, silver diffracted peaks were also observed for the samples synthesized at different calcination temperatures of 500°C, 700°C, 900°C except 1100°C, in addition to ZnO . TEM images indicated that the average size of ZnO : Ag -NPs increases with the amount of Ag concentration. The PL spectra of the samples revealed that the increase of Ag concentration results in the increase of the visible emission intensity, whereas by increasing the calcination temperature the intensity of visible emission of the samples decreases.


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