Effect of Milling Time on the Sensing Properties of Fly Ash Zeolite Composite Thin Films

Thin films, consisting of a sol–gel Nb2O5 matrix doped with zeolite Na-X synthesized from fly ash through ultrasonic-assisted double-stage fusion-hydrothermal alkaline activation, were deposited by the spin-coating method. In order to improve the optical quality and sensing properties of the thin films, zeolites were wet milled for 60, 120 and 540 s prior to incorporation in the film. The liquid adsorption ability of thin films was tested by measuring the reflectance spectra prior to and after exposure to liquid acetone and the change in the reflection coefficient ∆R of the films was calculated. The influence of milling time of zeolites on the sensing and optical properties of the films was studied.

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Effect of sapphire substrate orientations on the microstructural, optical and NO2 gas sensing properties of Zn(1−x)CdxO thin films synthesized by sol gel spin-coating method

Superlattices and Microstructures ◽

10.1016/j.spmi.2016.04.019 ◽

2016 ◽

Vol 94 ◽

pp. 158-177 ◽

Cited By ~ 2

Author(s):

M.A. Boukadhaba ◽

W. Chebil ◽

A. Fouzri ◽

V. Sallet ◽

A. Lusson ◽

...

Keyword(s):

Thin Films ◽

Sapphire Substrate ◽

Spin Coating ◽

Gas Sensing ◽

Sol Gel ◽

Sensing Properties ◽

Spin Coating Method ◽

Gas Sensing Properties ◽

Coating Method

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Acetone-Sensitive Thin Films Comprising Coal Fly Ash Na-X Zeolites and Sol–Gel Nb2O5 Matrix

Nanomaterials ◽

10.3390/nano11092399 ◽

2021 ◽

Vol 11 (9) ◽

pp. 2399

Author(s):

Katerina Lazarova ◽

Silviya Boycheva ◽

Marina Vasileva ◽

Denitza Zgureva-Filipova ◽

Biliana Georgieva ◽

...

Keyword(s):

Electron Microscopy ◽

Thin Films ◽

Fly Ash ◽

Coal Fly Ash ◽

Sol Gel ◽

Optical Quality ◽

Film Deposition ◽

Reflectance Spectra ◽

Raw Material ◽

X Zeolites

In this study, thin composite films of a sol–gel Nb2O5 matrix doped with coal fly ash Na-X zeolites were deposited by the spin-coating method. Fly ash of lignite coal collected from the electrostatic precipitators of one of the biggest TPPs in Bulgaria was used as a raw material for obtaining zeolites. Zeolite Na-X was synthesized by ultrasonic-assisted double stage fusion-hydrothermal alkaline conversion of coal fly ash. In order to improve the optical quality and sensing properties of the deposited thin films, synthesized zeolites were wet-milled for 60, 120, and 540 s prior to film deposition. The surface morphology of zeolite powders was studied both by scanning electron microscopy and transmission electron microscopy, while their porosity was investigated by N2-physisorption. Refractive index, extinction coefficient, and thickness of the films were determined through fitting of their reflectance spectra. The sensing ability of thin films towards acetone vapors was tested by measuring the reflectance spectra prior to and during exposure to the analyte, and the change in the reflection coefficient ∆R of the films was calculated. The influence of milling time of zeolites on the sensing and optical properties of the films was assumed and confirmed.

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Structure of Hydrogen Gas Sensing TiO2 Thin Films Prepared by Sol-Gel Method and their Comparison with Magnetron Sputtered Films

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.543.293 ◽

2013 ◽

Vol 543 ◽

pp. 293-296 ◽

Cited By ~ 3

Author(s):

G. Plesch ◽

A.A. Haidry ◽

M. Gregor ◽

P. Durina ◽

J. Gregus ◽

...

Keyword(s):

Thin Films ◽

Magnetron Sputtering ◽

Gas Sensing ◽

Sol Gel ◽

Rutile Phase ◽

Hydrogen Gas ◽

Gel Method ◽

Sensing Properties ◽

Sol Gel Method ◽

Coating Method

TiO2thin films with a thickness of about 150 nm were deposited by spin coating method on sapphire substrate from a sol-gel system. The hydrogen sensing properties of TiO2films annealed at various temperatures were studied and correlated with their structure, optical and electrical properties. The annealing temperatures in the range of 600 800 °C lead to anatase films with a roughness in the range of 0.6 0.9 nm. Their sensitivity towards hydrogen is low. The thin films annealed at temperatures in the range 900 1000 °C consist of rutile phase and their roughness increased to 11.7 13.5 nm. They showed good hydrogen sensitivity with optimal operating temperature 200 250 °C. The structure and sensing properties of the prepared films are compared with those synthesized with magnetron sputtering. The maximum of sensitivity was measured on the thin films with diameter of the grains about 100 nm in both cases, i.e. on thin films prepared by sol-gel method as well as on thin films prepared by magnetron sputtering. The maximum sensitivity correlates with the diameter of the grains and dont depend on the allotropy of the titanium dioxide anatase or rutile.

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Optical Properties of Nanostructured Sol–Gel Thin Films Doped with Fe2O3 and Their Ferromagnetic Characterization by Mössbauer Spectroscopy

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2008.18413 ◽

2008 ◽

Vol 8 (12) ◽

pp. 6491-6496

Author(s):

Jorge Garcia-Macedo ◽

Guadalupe Valverde-Aguilar ◽

Raúl W. Gómez ◽

José L. Pérez-Mazariego ◽

Vivianne Marquina

Keyword(s):

Thin Films ◽

Room Temperature ◽

Sol Gel ◽

Dip Coating ◽

Optical Quality ◽

X Ray Diffraction ◽

Glass Substrates ◽

Coating Method ◽

Dip Coating Method

Sol–gel thin films containing Fe2O3 were deposited onto glass substrates by the dip-coating method at room temperature. Fe2O3 enriched with the isotope 57Fe was embedded in two kinds of matrices: zinc oxide (ZnO) and silica (SiO2). X-ray diffraction (XRD) was used for morphology and structure determination of the nanostructures and showed that the ZnO exhibit a wurtzite form when the film is annealed at 450 °C for 20 min. SiO2 thin films at C16H33PEO20:Fe2O3 = 1:2.7 × 10−1 molar concentration exhibit a hexagonal nanophase produced by the diblock copolymer Brij58 (C16H33PEO20). Optical absorption and infrared spectroscopy techniques were used to evaluate the optical quality of the films. In order to determine if the Fe2O3 was incorporated into the matrices, room temperature Mössbauer spectra of both samples were obtained. In both cases the hematite spectrum was obtained, corroborating that the incorporation of the Fe2O3 to the matrices was done without chemical reaction whatsoever.

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