Hydrothermal Synthesis and Gas Sensing Properties of α-Fe2O3 Hollow Microspheres and Nanorods

2011 ◽  
Vol 343-344 ◽  
pp. 177-180
Author(s):  
Xia Lei Ye ◽  
Guo Han Liu ◽  
Yu Zhe Song ◽  
Gen Liang Han ◽  
Qi Hai Lu ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Hydrothermal Synthesis ◽  
Gas Sensing ◽  
Ethylenediaminetetraacetic Acid ◽  
Hollow Microspheres ◽  
X Ray Diffraction ◽  
X Ray ◽  
Gas Sensing Properties ◽  
Gas Response ◽  
Scanning Electron

α-Fe2O3 hollow microspheres and nanorods were synthesized via a hydrothermal method using glucose and ethylenediaminetetraacetic acid (EDTA) as morphology controlled agents, followed by calcination at 500 °C for 4 h in air. The crystal structures of products were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). The results show that the hollow microspheres with diameters of 1-2 μm are consist of nanoparticles (80-100 nm), and the nanorods have a structure in the diameter of 80-100 nm and length about 1 μm. Furthermore, the α-Fe2O3 hollow microspheres show higher gas response to ethanol than that of nanorods and nanoparticles.

A Novel Tungsten Trioxide Based Gas Sensor for Indoor Formaldehyde Detection

2021 ◽  
Vol 16 (3) ◽  
pp. 363-367
Author(s):  
Gaoqi Zhang ◽  
Fan Zhang ◽  
Kaifang Wang ◽  
Tao Tian ◽  
Shanyu Liu ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Gas Sensor ◽  
Indoor Air ◽  
Gas Sensing ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sensing Material ◽  
Transmission Electron ◽  
Gas Sensing Properties ◽  
Gas Response

Accurate and real-time detection of formaldehyde (HCHO) in indoor air is urgently needed for human health. In this work, a ceramic material (WO3·H2O) with unique structure was successfully prepared using an efficient hydrothermal method. The crystallinity, morphology and microstructure of the as-prepared sensing material were analyzed by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM) as well as transmission electron microscope (TEM). The characterization results suggest that the as-prepared sample is composed of square-like nanoplates with uneven surface. Formaldehyde vapor is utilized as the target gas to investigate gas sensing properties of the synthesized novel nanoplates. The testing results indicate that the as-fabricated gas sensor exhibit high gas response and excellent repeatability to HCHO gas. The response value (Ra/Rg) is 24.5 towards 70 ppm HCHO gas at 350 °C. Besides, the gas sensing mechanism was described.

Hydrothermal Preparation of B-Doped TiO2 and Photodegradation of Salicylic Acid under Visible Light

2012 ◽  
Vol 557-559 ◽  
pp. 1592-1595 ◽  
Author(s):  
Xiao Lin Liu ◽  
Wen Lu Guo ◽  
Jing Jing Ma
Keyword(s):  
Salicylic Acid ◽  
Electron Microscope ◽  
Hydrothermal Synthesis ◽  
Visible Light ◽  
Degradation Rate ◽  
Diffuse Reflectance ◽  
X Ray Diffraction ◽  
Hydrothermal Preparation ◽  
X Ray ◽  
Scanning Electron

B-doped TiO2 nanoparticles have been successfully prepared using hydrothermal synthesis with tetrabuttyl titanate and boric acid as precursor. The prepared samples were characterized by X-ray diffraction (XRD), UV-vis diffuse reflectance spectra (UV-vis DRS), scanning electron microscope (SEM). The B-doped TiO2 nanoparticles were red-shifted than P25. And the degradation rate of B-TiO2 is 72.62% in 120 min by degradation of salicylic acid under visible light irradiation.

scholarly journals Sputtered SnO2/ZnO Heterostructures for Improved NO2 Gas Sensing Properties

Chemosensors ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 67 ◽  
Author(s):  
Bharat Sharma ◽  
Ashutosh Sharma ◽  
Monika Joshi ◽  
Jae-ha Myung
Keyword(s):  
Photoelectron Spectroscopy ◽  
Gas Sensing ◽  
Operating Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Response Recovery ◽  
No2 Gas Sensor ◽  
Highly Sensitive ◽  
Gas Sensing Properties ◽  
Gas Response

A highly sensitive and selective NO2 gas sensor dependent on SnO2/ZnO heterostructures was fabricated using a sputtering process. The SnO2/ZnO heterostructure thin film samples were characterized by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), Energy-dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS). Sensors fabricated with heterostructures attained higher gas response (S = 66.9) and quicker response-recovery (20 s, 45 s) characteristics at 100 °C operating temperature towards 100 ppm NO2 gas efficiently in comparison to sensors based on their mono-counterparts. The selectivity and stability of SnO2/ZnO heterostructures were studied. The more desirable sensing mechanism of SnO2/ZnO heterostructures towards NO2 was described in detail.

Method for synthesizing ZnO of different nanostructures by electrospinning and study of their gas sensing properties

2019 ◽  
Vol 33 (25) ◽  
pp. 1950297
Author(s):  
Xiang-Bing Li ◽  
Shu-Yi Ma ◽  
Fu-Rong Li ◽  
Yu-Xiang Zhao ◽  
Xiao-Bin Liu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Gas Sensing ◽  
Component Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Electrospinning Method ◽  
Gas Sensing Properties ◽  
Zno Nanofibers ◽  
Scanning Electron

The properties of nanomaterials usually depend on their microstructures, the same material of different microstructures could be used for various applications. However, most devices could only synthesize a single microstructure, so it is meaningful that the different microstructures were synthesized by one method. In our study, electrospinning was applied to fabricate ZnO nanofibers and nanoparticles. In this approach, Zn(Ac)/PVP composite fibers of different component ratio were synthesized by electrospinning method which was subsequently calcined and formed ZnO nanofibers and nanoparticles. The microstructure, chemical composition and gas sensing were investigated with scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and WS-60A gas sensing measurement system. The synthesis mechanisms of ZnO nanofibers and nanoparticles were discussed in detail.

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.

Au-sensitized WO3 nanoparticles synthesized and their enhanced acetone sensing properties

2018 ◽  
Vol 11 (04) ◽  
pp. 1850071 ◽  
Author(s):  
Dongping Xue ◽  
Zhanying Zhang
Keyword(s):  
Recovery Time ◽  
Gas Sensing ◽  
Test Results ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sensing Properties ◽  
Response Recovery ◽  
Two Samples ◽  
Gas Sensing Properties ◽  
Scanning Electron

Au-sensitized WO3 nanoparticles have been synthesized by a facile two-step hydrothermal method. The structures, morphologies and surface compositions of the materials were characterized by X-ray diffraction (XRD), energy dispersive spectroscopy (EDS) and scanning electron microscopy (SEM). The test results show that we have prepared higher purity Au-sensitized WO3 nanoparticles. The gas-sensing properties of pure and Au-sensitized WO3 nanoparticles on acetone vapor were further investigated. The results obtained show that the response-recovery time of the two samples prepared is relatively short compared to that reported in the current literature. The Au-sensitized WO3 nanoparticles are significantly more sensitive and selective than the pure WO3 nanoparticles. This may be mainly attributed to the synergy between Au and WO3. It is expected that the Au-sensitized WO3 nanoparticles thus prepared can also be used for research in other fields.

A Novel Soft Paper Prepared by Hydrothermal Synthesis of Ultralong TiO2 Nanofibers

2014 ◽  
Vol 977 ◽  
pp. 86-89
Author(s):  
Yu Mei Gong ◽  
Yi Wen Li ◽  
Na Zhao ◽  
Mei Yan Chen ◽  
Hong Zhang ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Hydrothermal Synthesis ◽  
Scanning Electron Microscope ◽  
X Ray Diffraction ◽  
X Ray ◽  
Polarizing Microscope ◽  
Scanning Electron

In this paper, a kind of fibrous TiO2 has been prepared through hydrothermal synthesis and a paper fabricated from the fibrous TiO2 has been obtained. The composition, morphology, and size of the fibrous TiO2 were characterized by using X-ray diffraction (XRD) and scanning electron microscope (SEM) respectively. And the morphology of the paper was characterized by polarizing microscope. The thickness, softness, and writing properties of the paper were detected by a vernier caliper and a pen. The results indicate that the diameter of the fibrous TiO2 is ~ 200 nm, the thickness of the fabricated paper is ~ 0.35 mm, and the paper can be tolerated writing by a UM-100 ball pen. The excellent properties of the prepared paper may change the applications of fibrous TiO2 in papermaking industry.

scholarly journals Studies on Spray Pyrolised Nanostructured SnO2 Thin Films for H2 Gas Sensing Application

2014 ◽  
Vol 36 ◽  
pp. 125-141 ◽  
Author(s):  
R.H. Bari ◽  
S.B. Patil
Keyword(s):  
Thin Films ◽  
Gas Sensing ◽  
Spray Pyrolysis Technique ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sensing System ◽  
Gas Sensing Properties ◽  
Structural Surface ◽  
Diffraction Peaks ◽  
Gas Response

The objective of this work is to study the influence of pyrolysis temperature on structural, surface morphology and gas sensing properties of the nanostructured SnO2 thin films prepared by spray pyrolysis technique. These films were characterized for the structural, morphological and elemental composition carried by means of X-ray diffraction (XRD), scanning electron mi­croscopy (SEM) and energy dispersive spectrophotometer (EDAX). The information of crystallite size, dislocation density and microstrain is obtained from the full width-at half- maximum (FWHM) of the diffraction peaks. Effect of sprayed deposition temperature on H2 gas sensing performance and electrical properties were studied using static gas sensing system. The sensor (Tpyr. = 350°C) showed high gas response (S = 1200 at 350 °C) on exposure of 500 ppm of H2 and high selectivity against other gases The results are discussed and interpreted.

Synthesis of H-In2O3 and C-In2O3 by Different Methods and Gas Sensing Properties

2011 ◽  
Vol 284-286 ◽  
pp. 1006-1009
Author(s):  
Bin Wang ◽  
Fu Bo Gu ◽  
Dong Mei Han ◽  
Guang Sheng Guo
Keyword(s):  
Gas Sensing ◽  
Diffraction Field ◽  
Solvothermal Process ◽  
X Ray Diffraction ◽  
Reaction Conditions ◽  
X Ray ◽  
Sensing Properties ◽  
Gas Sensing Properties ◽  
One Step ◽  
Scanning Electron

In(OH)3 and InOOH were prepared through a simple hydrothermal method at different volume ratios of En and H2O. C-In2O3 and H-In2O3 were obtained by annealing these two precursors at 400°C in air, respectively. One-step In2O3 was also synthesized via solvothermal process using DEG as solvents. The effects of reaction conditions on phase structures and morphologies were studied. The gas sensing properties of the obtained materials toward ethanol were measured and X-ray diffraction, field-emission scanning electron microscope and PL were used to characterize the as-obtained products.

PENGGUNAAN TiO2 PARTIKEL NANO HASIL SINTESIS BERBASIS AIR MENGGUNAKAN METODA SOL-GEL PADA BAHAN KAPAS SEBAGAI APLIKASI UNTUK TEKSTIL ANTI UV

Arena Tekstil ◽  
2013 ◽  
Vol 28 (1) ◽  
Author(s):  
Maya Komalasari ◽  
Bambang Sunendar
Keyword(s):  
Fourier Transform ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Sol Gel ◽  
Crosslinking Agent ◽  
X Ray Diffraction ◽  
Nano Tio2 ◽  
X Ray ◽  
Infra Red ◽  
Scanning Electron

Partikel nano TiO2 berbasis air dengan pH basa telah berhasil disintesis dengan menggunakan metode sol-gel dan diimobilisasi pada kain kapas dengan menggunakan kitosan sebagai zat pengikat silang. Sintesis dilakukan  dengan prekursor TiCl4 pada konsentrasi 0,3 M, 0,5 M dan 1 M, dan menggunakan templat kanji dengan proses kalsinasi pada suhu 500˚C selama 2 jam. Partikel nano TiO2 diaplikasikan ke kain kapas dengan metoda pad-dry-cure dan menggunakan kitosan sebagai crosslinking agent. Berdasarkan hasil Scanning Electron Microscope (SEM),diketahui bahwa morfologi partikel TiO2 berbentuk spherical dengan ukuran nano (kurang dari 100 nm). Karakterisasi X-Ray Diffraction (XRD) menunjukkan adanya tiga tipe struktur kristal utama, yaitu (100), (101) dan (102) dengan fasa kristal yang terbentuk adalah anatase dan rutile. Pada karakterisasi menggunakan SEM terhadap serbuk dari TiO2 yang telah diaplikasikan ke permukaan kain kapas, terlihat adanya imobilisasi partikel nano TiO2 melalui ikatan hidrogen silang dengan kitosan pada kain kapas. Hasil analisa tersebut kemudian dikonfirmasi dengan FTIR (Fourier Transform Infra Red) yang hasilnya memperlihatkan puncak serapan pada bilangan gelombang 3495 cm-1, 2546 cm-1, dan 511 cm-1,  yang masing-masing diasumsikan sebagai adanya vibrasi gugus fungsi O-H, N-H dan Ti-O-Ti. Hasil SEM menunjukkan pula bahwa kristal nano yang terbentuk diantaranya adalah fasa rutile , yang berdasarkan literatur terbukti dapatberfungsi sebagai anti UV.

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