Porous LaFeO3 with High Response to Acetone Synthesized from Biotemplates

2013 ◽  
Vol 575-576 ◽  
pp. 20-23 ◽  
Author(s):  
Yu Zhen Ma ◽  
Peng Song ◽  
Qi Wang
Keyword(s):  
Electron Microscopy ◽  
Gas Sensing ◽  
Perovskite Phase ◽  
Spherical Particles ◽  
Orthorhombic Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Xrd Patterns ◽  
Microscopy Characterization

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.

scholarly journals Effect of Growth Temperature and Time on Morphology and Gas Sensitivity of Cu2O/Cu Microstructures

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Ling Wu ◽  
Lun Zhang ◽  
Zhipeng Xun ◽  
Guili Yu ◽  
Liwei Shi
Keyword(s):  
Electron Microscopy ◽  
Gas Sensors ◽  
Gas Sensing ◽  
Spherical Particles ◽  
X Ray Diffraction ◽  
Gas Sensitivity ◽  
X Ray ◽  
Transmission Electron ◽  
Wide Range ◽  
Gas Response

A facile hydrothermal synthesis with CuSO4as the copper source was used to prepare micro/nano-Cu2O. The obtained samples have been characterized by X-ray diffraction, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). With increasing the reaction temperature and time, the final products were successively Cu2O octahedron microcrystals, Cu2O/Cu composite particles, and a wide range of Cu spherical particles. The gas sensitivity of products towards ethanol and acetone gases was studied. The results showed that sensors prepared with Cu2O/Cu composites synthesized at 65°C for 15 min exhibited optimal gas sensitivity. The gas sensing mechanism and the effect of Cu in the enhanced gas response were also elaborated. The excellent gas sensitivity indicates that Cu2O/Cu composites have potential application as gas sensors.

Clay minerals in the Namacotche Pegmatite Group from Zambezia Province, Mozambique: main constituents of late-stage secondary paragenesis

Clay Minerals ◽  
2008 ◽  
Vol 43 (4) ◽  
pp. 597-613 ◽  
Author(s):  
M. A. Sequeira Braga ◽  
C. Leal Gomes ◽  
J. Duplay ◽  
H. Paquet
Keyword(s):  
Electron Microscopy ◽  
Clay Minerals ◽  
Late Stage ◽  
Polarized Light ◽  
Chemical Analyses ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Close Relationship ◽  
Xrd Patterns

AbstractNamacotche gem-bearing pegmatites of Alto Ligonha pegmatite district are heterogeneous, strongly fractionated, and have large Li and Ta and extremely large Cs contents. Clay samples were collected in fracture infillings and dilation cavities with gemstones and were studied using X-ray diffraction (XRD), polarized light microscope, scanning electron microscopy-energy dispersive spectroscopy, high-resolution transmission electron microscopy and chemical analyses. The <2 μm fraction contains cookeite, illite, illite-smectite and suggested irregular mixed-layer cookeite-smectite, beidellite, montmorillonite, kaolinite and goethite.The XRD patterns of chlorite and their d values suggest the presence of ‘di-trioctahedral chlorite’ similar to cookeite-Ia polytype. Cookeite chemical analyses show that Li contents range from 0.82 to 1.08 atoms per half unit cell.A close relationship has been established between occurrences of gemstones and clay minerals. Some important textures and crystal chemistry are discussed.The main gemstones related to the Namacotche Pegmatite are: morganite (pink cesian beryl), kunzite (spodumene) and elbaite tourmaline. As the mechanisms responsible for the gemstone formation take place at low temperature, the clay minerals paragenesis cookeite ± cookeite-smectite interstratification ± beidellite + montmorillonite ± illite-smectite interstratification, represents a late-stage secondary paragenesis, generated by hydrothermal alteration.

scholarly journals Highly sensitive and selective sensing of H2S gas using precipitation and impregnation-made CuO/SnO2 thick films

2021 ◽  
Author(s):  
Pimpan Leangtanom ◽  
Anurat Wisitsoraat ◽  
Kata Jaruwongrangsee ◽  
Narong Chanlek ◽  
Adisorn Tuantranont ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Gas Sensing ◽  
Fast Response ◽  
Potential Candidate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cu Content ◽  
Transmission Electron ◽  
Highly Sensitive

Abstract In this work, CuO-loaded tetragonal SnO2 nanoparticles (CuO/SnO2 NPs) were synthesized using precipitation/impregnation methods with varying Cu contents of 0–25 wt% and characterized for H2S detection. The material phase, morphology, chemical composition and specific surface area of NPs were evaluated using X-ray diffraction, transmission electron microscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy and Brunauer-Emmett-Teller analysis. From gas-sensing data, the H2S responses of SnO2 NPs were greatly enhanced by CuO loading particularly at the optimal Cu content of 20 wt%. The 20 wt%CuO/SnO2 sensor showed an excellent response of 1.36⋅105 towards 10 ppm H2S and high H2S selectivity against H2, SO2, CH4 and C2H2 at a low optimum working temperature of 200°C. In addition, the sensor provided fast response and a low detection limit of less than 0.15 ppm. The CuO-SnO2 sensor could therefore be a potential candidate for H2S detection in environmental applications.

Nanostructured CaWO4, CaWO4:Eu3+ and CaWO4:Tb3+ Particles: Sonochemical Synthesis and Luminescent Properties

2008 ◽  
Vol 8 (3) ◽  
pp. 1183-1190 ◽  
Author(s):  
Chunxia Li ◽  
Cuikun Lin ◽  
Xiaoming Liu ◽  
Jun Lin
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Field Emission ◽  
Spherical Particles ◽  
X Ray Diffraction ◽  
Blue Emission Band ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

Nanostructured CaWO4, CaWO4:Eu3+, and CaWO4:Tb3+ phosphor particles were synthesized via a facile sonochemical route. X-ray diffraction, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, photoluminescence, low voltage cathodoluminescence spectra, and photoluminescence lifetimes were used to characterize the as-obtained samples. The X-ray diffraction results indicate that the samples are well crystallized with the scheelite structure of CaWO4. The transmission electron microscopy and field emission scanning electron microscopy images illustrate that the powders consist of spherical particles with sizes from 120 to 160 nm, which are the aggregates of even smaller nanoparticles ranging from 10 to 20 nm. Under UV light or electron beam excitation, the CaWO4 powder exhibited a blue emission band with a maximum at 430 nm originating from the WO2−4 groups, while the CaWO4:Eu3+ powder showed red emission dominated by 613 nm ascribed to the 5D0 → 7F2 of Eu3+, and the CaWO4:Tb3+ powders showed emission at 544 nm, ascribed to the 5D4 → 7F5 transition of Tb3+. The PL excitation and emission spectra suggest that the energy is transferred from WO2−4 to Eu3+CaWO4:Eu3+ and to Tb3+ in CaWO4:Tb3+. Moreover, the energy transfer from WO2−4 to Tb3+ in CaWO4:Tb3+ is more efficient than that from WO2−4 to Eu3+ in CaWO4:Eu3+. This novel and efficient pathway could open new opportunities for further investigating the novel properties of tungstate materials.

scholarly journals Synthesis of Flower-Like Cu2ZnSnS4Nanoflakes via a Microwave-Assisted Solvothermal Route

2014 ◽  
Vol 2014 ◽  
pp. 1-4 ◽  
Author(s):  
Fei Long ◽  
Shuyi Mo ◽  
Yan Zeng ◽  
Shangsen Chi ◽  
Zhengguang Zou
Keyword(s):  
Electron Microscopy ◽  
Raman Scattering ◽  
Zinc Acetate Dihydrate ◽  
X Ray Diffraction ◽  
One Pot ◽  
X Ray ◽  
Transmission Electron ◽  
Direct Band ◽  
Xrd Patterns ◽  
Average Size

Flower-like Cu2ZnSnS4(CZTS) nanoflakes were synthesized by a facile and fast one-pot solution reaction using copper(II) acetate monohydrate, zinc acetate dihydrate, tin(IV) chloride pentahydrate, and thiourea as starting materials. The as-synthesized samples were characterized by X-ray diffraction (XRD), Raman scattering analysis, field emission scanning electron microscopy (FESEM) equipped with an energy dispersion X-ray spectrometer (EDS), transmission electron microscopy (TEM), and UV-Vis absorption spectra. The XRD patterns shown that the as-synthesized particles were kesterite CZTS and Raman scattering analysis and EDS confirmed that kesterite CZTS was the only phase of product. The results of FESEM and TEM show that the as-synthesized particles were flower-like morphology with the average size of 1~2 μm which are composed of 50 nm thick nanoflakes. UV-Vis absorption spectrum revealed CZTS nanoflakes with a direct band gap of 1.52 eV.

scholarly journals Flame-Made Pt-Loaded TiO2Thin Films and Their Application as H2Gas Sensors

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Weerasak Chomkitichai ◽  
Hathaithip Ninsonthi ◽  
Chaikarn Liewhiran ◽  
Anurat Wisitsoraat ◽  
Saengrawee Sriwichai ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Gas Sensing ◽  
Pt Nanoparticles ◽  
Hydrogen Gas ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Hydrogen Gas Sensors ◽  
Operating Temperatures ◽  
Xrd Patterns ◽  
Deposited Film

The hydrogen gas sensors were developed successfully using flame-made platinum-loaded titanium dioxide (Pt-loaded TiO2) nanoparticles as the sensing materials. Pt-loaded TiO2thin films were prepared by spin-coating technique onto Al2O3substrates interdigitated with Au electrodes. Structural and gas-sensing characteristics were examined by using scanning electron microscopy (SEM) and showed surface morphology of the deposited film. X-ray diffraction (XRD) patterns can be confirmed to be the anatase and rutile phases of TiO2. High-resolution transmission electron microscopy (HRTEM) showed that Pt nanoparticles deposited on larger TiO2nanoparticles. TiO2films loaded with Pt nanoparticles were used as conductometric sensors for the detection of H2. The gas sensing of H2was studied at the operating temperatures of 300, 350, and 400°C in dry air. It was found that 2.00 mol% Pt-loaded TiO2sensing films showed higher response towards H2gas than the unloaded film. In addition, the responses of Pt-loaded TiO2films at all operating temperatures were higher than that of unloaded TiO2film. The response increased and the response time decreased with increasing of H2concentrations.

Initial formation mechanisms of (Ga1−xMnx)N nanorods grown on Al2O3 (0001) substrates

2008 ◽  
Vol 23 (12) ◽  
pp. 3275-3280 ◽  
Author(s):  
K.H. Lee ◽  
J.Y. Lee ◽  
H.C. Jeon ◽  
T.W. Kang ◽  
H.Y. Kwon ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Molecular Beam ◽  
Formation Mechanisms ◽  
X Ray Diffraction ◽  
Initial Formation ◽  
X Ray ◽  
Transmission Electron ◽  
High Resolution Tem ◽  
Xrd Patterns ◽  
Scanning Electron

The (Ga1−xMnx)N nanorods were grown on Al2O3 (0001) substrates by using rf-associated molecular beam epitaxy. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and selected-area diffraction pattern (SADP) results showed that the (Ga1−xMnx)N nanorods had (0001) preferential orientations. XRD patterns showed that the (Ga1−xMnx)N nanorods contained a small number of grains with different preferred orientations. High-resolution TEM (HRTEM) images showed that the (Ga1−xMnx)N nanorods consisted of different preferentially oriented grains. The initial formation mechanisms for the (Ga1−xMnx)N nanorods grown on Al2O3 (0001) substrates are described on the basis of the XRD, the TEM, the SADP, and the HRTEM results.

A Metastable Ion (III) Oxide Phase (ε-Fe2O3): Preparation and Gas Sensing Properties

2016 ◽  
Vol 697 ◽  
pp. 737-740 ◽  
Author(s):  
Ming Jing Wang ◽  
Hui Ming Ji ◽  
Ya Lu Chen ◽  
Qian Qian Jia
Keyword(s):  
Electron Microscopy ◽  
Gas Sensing ◽  
Sol Gel ◽  
Oxide Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Gas Sensing Properties ◽  
Addition Amount ◽  
Scanning Electron

ε-Fe2O3 is a rare and metastable iron (III) oxide phase. ε-Fe2O3/SiO2 composites were prepared by combining the reverse-micelle and sol-gel methods. An appropriate amount of Ba2+ was needed in this system to promote the formation of ε-Fe2O3 nanorods in SiO2. The size of nanorods varied with different Ba2+ addition amount and sintering procedure. Then pure ε-Fe2O3 nanorods were obtained after stripping SiO2 by etching due to NaOH aqueous solution. The as-synthesized ε-Fe2O3 nanorods were discussed using X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscopy (TEM). Interestingly, metastable ε-Fe2O3 nanorods showed a promising performance for the response for ethanol, compared with the stable phases of α-Fe2O3 and γ-Fe2O3. It indicates that nanostructure ε-Fe2O3 (including ε-Fe2O3 nanorods) could be a valuable material for the fabrication of advanced sensing devices.

Synthesis and Characterization of a New Amino-Functionalized PMO Material

2013 ◽  
Vol 712-715 ◽  
pp. 271-279
Author(s):  
Fei Ding ◽  
Shuang Xi Liu
Keyword(s):  
Electron Microscopy ◽  
Solid State Nmr ◽  
Alkyl Chain ◽  
Reaction System ◽  
Synthesis And Characterization ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Xrd Patterns

A new organic silicane which is bridged by a long amino-functionalized alkyl chain was prepared and used as the precursor in the synthesis of a series of PMO materials. The organic silicane was added into the reaction system in CH2Cl2and the PMO materials were prepared by a simple stirring method under acidic condition, with a nonionic surfactantBrij 76 as template. To find the proper synthesis condition, the time of stirring and the proportion of organic silicane and TEOS were varied. Liquid and solid state NMR, X-ray diffraction (XRD) patterns, thermogravimetric analysis (TGA), transmission electron microscopy (TEM) and N2-physisorption properties were used to characterize the structures.

scholarly journals Synthesis and application of pigments based on lanthanide orthoferrites

2020 ◽  
Vol 14 (2) ◽  
pp. 161-167
Author(s):  
Patrícia Pimentel ◽  
Jairo Dutra ◽  
Maria Câmara ◽  
Gerbeson Dantas ◽  
Osmar Bagnato ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Perovskite Phase ◽  
Visible Region ◽  
Ceramic Pigments ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Uv Visible ◽  
Cie Lab

In this work, we synthesized oxides with perovskite LnFeO3 type structure (where Ln = La, Pr and Nd), aiming their use as ceramic pigments. The as-synthesized powders, prepared by gelatin method, were thermally treated at 600 and 800 ?C to obtain the perovskite phase. The characterization was performed using X-ray diffraction technique, followed by Rietveld refinement, scanning and transmission electron microscopy, spectroscopy in the UV-Visible region and CIE Lab colorimetry. The calcined powders were also used for fabrication of ceramic pieces to evaluate the colour when 2 wt.% of the powders was added into a transparent glaze. The pigments presented shades ranging from pale brown for the powdered samples to yellowish when applied in the glazes.

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