Mesostructured WO3 as a sensing material for NO2 detection

2006 ◽  
Vol 915 ◽  
Author(s):  
E. Rossinyol ◽  
A. Prim ◽  
E. Pellicer ◽  
J. Arbiol ◽  
F. Peiró ◽  
...  
Keyword(s):  
Tungsten Oxide ◽  
Photoelectron Spectroscopy ◽  
Gas Sensing ◽  
Sensor Response ◽  
Material Surface ◽  
Type I ◽  
X Ray ◽  
Sensing Material ◽  
Catalytic Additive ◽  
No2 Detection

AbstractNanostructured tungsten oxide synthesized from SiO2 templates (SBA-15 and KIT-6) has been used for NO2 gas sensing. Chromium has been added as catalytic additive to WO3 in order to enhance sensor response. Several techniques have been used for identifying both additive location in the tungsten oxide matrix and its oxidation state. Raman spectroscopy confirmed the presence of terminal chromium-oxygen bonds at the material surface. Besides, X-ray photoelectron spectroscopy showed chromium peaks attributable to Cr(III) species. Electrical behavior of pure WO3 has found to be highly dependent on the nanostructure type, i. e. 2D SBA-15 and 3D KIT-6 replicas. Chromium addition diminishes response time and improves sensor response at low NO2 concentrations. Electrical differences due to WO3 nanostructure disappears as a result of additive introduction in the material.

Synthesis of Co3O4 Multilayer Nanosheet Material and its Promising Gas Sensing Property

2014 ◽  
Vol 937 ◽  
pp. 231-236 ◽  
Author(s):  
Ming Li Yin ◽  
Sheng Zhong Liu
Keyword(s):  
Photoelectron Spectroscopy ◽  
Gas Sensing ◽  
Annealing Treatment ◽  
Solution Concentration ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sensing Material ◽  
Ethanol Resistance ◽  
Structure Morphology ◽  
P Type

Co3O4multilayer nanosheets were synthesized by a hydrothermal method and a post annealing treatment process. The effect of solution concentration and ratio on the morphology of Co3O4precursor was studied. The crystalline structure, morphology and elemental composition of Co3O4multilayer nanosheets were characterized by X-ray diffraction, scanning electron microscopy and X-ray photoelectron spectroscopy technologies. When exposed to reducing gas such as ethanol, resistance of Co3O4multilayer nanosheet sensor increases quickly, demonstrating that the Co3O4multilayer nanosheets are p-type conductivity. For 100 ppm alcohol at 240 °C, the sensor response is as high as 32, indicating that the powder of Co3O4multilayer nanosheets is a very promising low-powder gas sensing material.

scholarly journals Soft x-ray photoelectron spectroscopy study of type-I clathrates

2008 ◽  
Vol 9 (4) ◽  
pp. 044207 ◽  
Author(s):  
Jun Tang ◽  
Zhaofei Li ◽  
Jing Ju ◽  
Ryotaro Kumashiro ◽  
Marcos A. Avila ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Type I ◽  
Spectroscopy Study ◽  
X Ray

scholarly journals Yttrium Doped TiO2 Thin Film for Gas Sensing Application Prepared by Spin Coating Method

2020 ◽  
Author(s):  
M Abdul Kaiyum ◽  
Naim Ahmed ◽  
Arif Alam ◽  
M Shamimur Rahman
Keyword(s):  
Thin Film ◽  
Photoelectron Spectroscopy ◽  
Gas Sensing ◽  
Low Cost ◽  
Pure Titanium ◽  
X Ray ◽  
Sensing Applications ◽  
Coating Method ◽  
Set Up ◽  
Spin Coater

Abstract Yttrium (Y) doped and pure Titanium Di-oxide (TiO2) thin films were prepared by using spin coater. The coater was set up in laboratory with low cost investment. The films were calcined at 450 °C for 1 hour. For characterization, Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Analysis (EDX), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Atomic Force Microscopy (AFM) were carried out. LCR Bridge - GW Instek LCR-821 was used for gas sensing applications. XPS showed that the change of electronic structure due to Y doping. SEM and AFM analysis were carried out to determine the surface morphology of the films. Yttrium (Y) decreased the crystallite size of the films and increased the surface roughness and porosity value, which was very good for many sensing applications. Gas sensing property of the deposited films were improved by the incorporation of yttrium impurities and the sensing property improved almost two times than pure TiO2 thin film. Different researches have been done their research related to this topic but no one researchers provide a precise explanation of their results, authors of this research have tried to do that. Moreover the films were prepared by a simple spin coater to reduce the production cost also.

The Surface Modification and Characteristics of Useful Expanded PTFE Composites by Photo-Radiation Methods

2013 ◽  
Vol 690-693 ◽  
pp. 1636-1640 ◽  
Author(s):  
Te Hsing Wu ◽  
Ko Shao Chen ◽  
Lie Hang Shen
Keyword(s):  
Contact Angle ◽  
Acetic Acid ◽  
Photoelectron Spectroscopy ◽  
Plasma Deposition ◽  
Material Surface ◽  
Water Contact ◽  
X Ray ◽  
Hydrogel Film ◽  
Γ Ray ◽  
Ptfe Composites

In this study, We immobilized hydrogel material onto expanded polytetrafluoroethylene (ePTFE) film and used as an functional biomaterial. The material is a film containing titanium oxide onto polymer sheet. The hydrogel film is hydrophilic, bacterial inactivated and bio-compatible. In order to improve the ePTFE film biocompatibility, the cold plasma or γ-ray technology was used with acetic acid as monomer to deposit onto ePTFE film and then (N-isopropylacrylamide) was grafted onto the surface by radiation photo-grafting. The characteristics of the material surface were evaluated with X-ray photoelectron spectroscopy (XPS), FTIR and water contact angle. It was found that the contact angle of water on the untreated ePTFE significantly decrease from125° to 72° after ePTFE film being treated with acetic acid plasma deposition procedure. Due to the hydrophilicity of poly (N-isopropylacrylamide), so the contact angle of water on the ePTFE-g-NIPAAm almost approached to 0°. This thermal sensitive ePTFE hydrogels can be applied to artificial guiding tube and wound dressing material.

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.

scholarly journals Surface-Modified Poly(l-lactide-co-glycolide) Scaffolds for the Treatment of Osteochondral Critical Size Defects—In Vivo Studies on Rabbits

2020 ◽  
Vol 21 (20) ◽  
pp. 7541
Author(s):  
Małgorzata Krok-Borkowicz ◽  
Katarzyna Reczyńska ◽  
Łucja Rumian ◽  
Elżbieta Menaszek ◽  
Maciej Orzelski ◽  
...  
Keyword(s):  
Bone Tissue ◽  
Tissue Regeneration ◽  
Photoelectron Spectroscopy ◽  
Sessile Drop ◽  
Bone Tissue Regeneration ◽  
In Vivo Studies ◽  
In Vivo Model ◽  
Type I ◽  
X Ray

Poly(l-lactide-co-glycolide) (PLGA) porous scaffolds were modified with collagen type I (PLGA/coll) or hydroxyapatite (PLGA/HAp) and implanted in rabbits osteochondral defects to check their biocompatibility and bone tissue regeneration potential. The scaffolds were fabricated using solvent casting/particulate leaching method. Their total porosity was 85% and the pore size was in the range of 250–320 µm. The physico-chemical properties of the scaffolds were evaluated using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffractometry (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), sessile drop, and compression tests. Three types of the scaffolds (unmodified PLGA, PLGA/coll, and PLGA/HAp) were implanted into the defects created in New Zealand rabbit femoral trochlears; empty defect acted as control. Samples were extracted after 1, 4, 12, and 26 weeks from the implantation, evaluated using micro-computed tomography (µCT), and stained by Masson–Goldner and hematoxylin-eosin. The results showed that the proposed method is suitable for fabrication of highly porous PLGA scaffolds. Effective deposition of both coll and HAp was confirmed on all surfaces of the pores through the entire scaffold volume. In the in vivo model, PLGA and PLGA/HAp scaffolds enhanced tissue ingrowth as shown by histological and morphometric analyses. Bone formation was the highest for PLGA/HAp scaffolds as evidenced by µCT. Neo-tissue formation in the defect site was well correlated with degradation kinetics of the scaffold material. Interestingly, around PLGA/coll extensive inflammation and inhibited tissue healing were detected, presumably due to immunological response of the host towards collagen of bovine origin. To summarize, PLGA scaffolds modified with HAp are the most promising materials for bone tissue regeneration.

Structural Changes on Photochromism of Organic-Inorganic Hybrid Materials

1999 ◽  
Vol 604 ◽  
Author(s):  
Keiichi Kuboyama ◽  
Kazumi Matsushige
Keyword(s):  
Fourier Transform ◽  
Tungsten Oxide ◽  
Transition Metal Oxides ◽  
Photoelectron Spectroscopy ◽  
Structural Changes ◽  
Spectroscopic Measurement ◽  
Inorganic Hybrid ◽  
X Ray ◽  
Oxide Hydrate ◽  
Ft Ir

AbstractSome transition metal oxides are known to exhibit the reversible coloration phenomena. Tungsten oxide is one of such materials and exhibits the photochromism and the electrochromism. It is known that the coloration phenomena in the tungsten oxide hydrate are caused by the redox reaction. We found that the photochromic efficiency became extremely higher by addition of some organic materials to the tungsten oxide hydrate and we have studied the mechanism of such a remarkable photochromic enhancement. In some spectroscopic measurement as FT-IR (Fourier transform infrared spectroscopy) and XPS (X-ray photoelectron spectroscopy), we obtained interesting features as follows. The addition of an organic material leads to reducing the tungsten oxide hydrate to smaller pieces, that is, the surface area of the pieces that can react with the additive increases. Moreover, it was found that specific sites in the additive are oxidized when the sample colors. The fact suggests that the additives having such specific sites can enhance the photochromism of the tungsten oxide hydrate

scholarly journals Facile Preparation of g-C3N4-WO3 Composite Gas Sensing Materials with Enhanced Gas Sensing Selectivity to Acetone

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Xiangfeng Chu ◽  
Junsong Liu ◽  
Shiming Liang ◽  
Linshan Bai ◽  
Yongping Dong ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Gas Sensing ◽  
Hydrothermal Processing ◽  
Optimum Temperature ◽  
X Ray ◽  
Gas Sensing Properties ◽  
Facile Preparation ◽  
Adsorption Desorption ◽  
Scanning Electron

In this paper, g-C3N4-WO3 composite materials were prepared by hydrothermal processing. The composites were characterized by means of X-ray powder diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and N2 adsorption-desorption, respectively. The gas sensing properties of the composites were investigated. The results indicated that the addition of appropriate amount of g-C3N4 to WO3 could improve the response and selectivity to acetone. The sensor based on 2 wt% g-C3N4-WO3 composite showed the best gas sensing performances. When operating at optimum temperature of 310°C, the responses to 1000 ppm and 0.5 ppm acetone were 58.2 and 1.6, respectively, and the ratio of the S1000 ppm acetone to S1000 ppm ethanol reached 3.7.

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